Co-reporter:Jie Dong, Qin Wang, Yujie Zhang, Zhaoqi Zhu, Xianghong Xu, Junping ZhangAiqin Wang
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 2) pp:
Publication Date(Web):December 21, 2016
DOI:10.1021/acsami.6b13539
Superamphiphobic coatings with low sliding angles (SAs) and high durability are very attractive in academic and industrial areas but are very challenging to invent. Here, inspired by Maya Blue, we report for the first time colorful superamphiphobic coatings with low SAs and high durability by the combination of natural palygorskite (PAL) nanorods and organosilanes. The coatings were characterized using a wide range of electron microscopy and other analytical techniques. Different from the previously reported methods, the micro/nanostructure of the superamphiphobic coatings were constructed by using the abundant natural PAL nanorods as the building blocks. Superamphiphobicity of the coatings depends on surface morphology and chemical composition of the coatings, which can be regulated by the concentrations of PAL and organosilanes. The colorful superamphiphobic coatings feature high contact angles and low SAs for various liquids, including water and n-decane. The coatings also showed high mechanical, environmental, chemical, and thermal durability even under harsh conditions. Moreover, the coatings in different colors with comparable superamphiphobicity and durability can be prepared using different cationic dyes applied onto various substrates via the same approach. The colorful superamphiphobic coatings with low SAs and high durability may be useful in various fields, e.g., anticreeping of oils and restoration of cultural relics.Keywords: Maya Blue; palygorskite/attapulgite; silanes; superhydrophobic; superoleophobic;
Co-reporter:Junping Zhang;Ziqian Gao;Lingxiao Li;Bucheng Li;Hanxue Sun
Advanced Materials Interfaces 2017 Volume 4(Issue 19) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/admi.201700723
AbstractPractical applications of superhydrophobic coatings are hindered by some issues, such as harmful chemicals, low mechanical durability, complicated methods, and expensive building blocks, etc. This study reports preparation of waterborne nonfluorinated superhydrophobic coatings with exceptional mechanical durability based on natural nanorods, palygorskite (PAL). A polyurethane (PU) aqueous solution and the homogeneous methyl polysiloxane-modified PAL (PAL@M-POS) suspension composed of methyltrimethoxysilane and the PAL nanorods in water are layer-by-layer spray-coated onto glass slides for two times with PU as the adhesive layer. The PAL@M-POS suspensions and the superhydrophobic PU/PAL@M-POS coatings are studied using various analytical techniques. The influences of PAL and methyltrimethoxysilane on microstructure, wettability, and mechanical durability of the coatings are also investigated. The PU/PAL@M-POS coatings feature high water contact angle (157.9°), low sliding angle (7.2°), and exceptional mechanical durability against sandpaper abrasion for 80 m and peeling with adhesive tape for 100 cycles. The mechanism behind the high mechanical durability is proposed. Also, the totally green method is simple, low-cost, scalable, and applicable onto various substrates, which have paved the way for practical applications of the durable superhydrophobic coatings. This work provides a new avenue for the fabrication of waterborne, nonfluorinated, and mechanically durable superhydrophobic coatings using abundant natural nanomaterials.
Co-reporter:Xia Zhao, Bo Yu, Junping Zhang
Journal of Colloid and Interface Science 2017 Volume 501(Volume 501) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.jcis.2017.04.049
Although thousands of superhydrophobic coatings have been reported, transparent ones with high durability are rare. Here, transparent and durable superhydrophobic coatings were prepared by using multiwalled carbon nanotubes (MWCNTs) as the templates. The superhydrophobic coatings were prepared by spray-coating the homogeneous suspension of polysiloxane-modified MWCNTs (MWCNTs@POS) in toluene onto glass slides, calcination in air at 500 °C to form the silica nanotubes (SNTs), and then chemical vapor deposition of polydimethylsiloxane at 200 °C onto the surface of the SNTs coatings. The MWCNTs@POS suspension was prepared by hydrolytic condensation of hexadecyltrimethoxysilane and tetraethoxysilane on the surface of MWCNTs. The coatings showed excellent superhydrophobicity (water contact angle = 166.6°, sliding angle = 1°) and high transparency (83.1% at 600 nm). In addition, the transparent superhydrophobic coatings featured high mechanical, chemical and thermal durability. The coatings retained the excellent superhydrophobicity after intensive water jetting at 100 kPa for 60 min, immersion in various corrosive liquids for 24 h, or kept at 390 °C for 1 h. Moreover, the transparent and durable superhydrophobic coatings exhibited very good anti-bioadhesive properties.Download high-res image (90KB)Download full-size image
Co-reporter:Lingxiao Li;Bucheng Li;Hanxue Sun
Journal of Materials Chemistry A 2017 vol. 5(Issue 28) pp:14858-14864
Publication Date(Web):2017/07/18
DOI:10.1039/C7TA03511J
Carbon aerogels are receiving great attention in academia and industry; however, the preparation of high performance carbon aerogels is challenging. Here, we report the preparation of compressible and conductive carbon aerogels (3C aerogels) from waste paper using a general “oxidation-oven drying-carbonization” method. The 3C aerogels are lightweight (23.6 mg cm−3) and show good electrical conductivity (0.051 S cm−1), high compressibility, superhydrophobicity/superoleophilicity and high oil absorption capacity (33–70 g g−1). The 3C aerogels can also be used for the removal of free oils in water via different approaches. Moreover, the 3C aerogels can be used for efficient gravity-driven separation of surfactant-stabilized water-in-oil emulsions and simultaneous adsorption of soluble organic pollutants in the emulsions, both in the water phase and in the oil phase. The 3C aerogels may also find applications in other fields including sensors and pressure-sensitive electronics. This work opens a new avenue for designing carbon aerogels with exceptional performance for oil/water separation.
Co-reporter:Junping ZhangBo Yu, Ziqian Gao, Bucheng Li, Xia Zhao
Langmuir 2017 Volume 33(Issue 2) pp:
Publication Date(Web):December 27, 2016
DOI:10.1021/acs.langmuir.6b04213
Although encouraging progress in the field of superamphiphobic coatings has been obtained, the superamphiphobic coatings with high durability, transparency, and repellency to hot liquids are very rare. Here, durable, transparent, and hot liquid-repelling superamphiphobic coatings were successfully prepared using polysiloxane-modified multiwalled carbon nanotubes (MWCNTs@POS) as the templates. The hydrolytic condensation of n-hexadecyltrimethoxysilane (HDTMS) and tetraethoxysilane on the surface of MWCNTs formed MWCNTs@POS, which are highly dispersible in toluene. The superamphiphobic coatings were prepared by spray-coating the homogeneous suspension of MWCNTs@POS in toluene onto glass slides, calcination in air to form the silica nanotubes (SNTs), and then modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane in dry toluene. The changes in the surface microstructure, surface chemical composition, and wettability were characterized by various techniques such as scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the microstructures of the SNTs have great influences on superamphiphobicity and transparency of the coatings and can be regulated by the concentration of HDTMS and the diameter of MWCNTs. The SNTs with tunable wall thickness and diameter could be obtained using the method. The superamphiphobic coatings showed high contact angles and low sliding angles for various cool and hot liquids of different surface tensions. The superamphiphobic coatings also exhibited high transparency and comprehensive durability.
Co-reporter:Bucheng Li, Junping Zhang, Ziqian Gao and Qingyun Wei
Journal of Materials Chemistry A 2016 vol. 4(Issue 3) pp:953-960
Publication Date(Web):07 Dec 2015
DOI:10.1039/C5TA08733C
Semitransparent superoleophobic coatings with low sliding angles for hot liquids are successfully prepared by fabrication of silica nanotubes (SNTs) on glass slides, and then modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane. The SNT layers are formed by spray-coating a homogeneous dispersion of polydimethylsiloxane (PDMS)-modified multiwalled carbon nanotubes (MWCNTs) onto glass slides followed by calcination to remove MWCNTs, the templates. The successful fabrication of SNTs and the superoleophobic coatings are confirmed by scanning electron microscopy, transmitting electron microscopy, X-ray photoelectron spectroscopy and investigation of the wetting behavior of n-decane on the coatings, etc. The microstructures of the SNT layers have great influence on superoleophobicity of the coatings, which are controllable by simply regulating the diameter of MWCNTs and the concentrations of MWCNTs and PDMS. The superoleophobic coatings feature high contact angles and low sliding angles for various liquids (such as water, toluene, n-hexadecane, n-decane, etc.), excellent superoleophobicity for hot liquids and good transparency.
Co-reporter:Yujie Zhang, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 3) pp:901-907
Publication Date(Web):03 Dec 2015
DOI:10.1039/C5TA09300G
The inferior stability of most Maya blue-like pigments to ancient Maya blue seriously hinders their practical applications. Inspired by self-cleaning and water-repellent properties of the lotus leaf in the natural world, biomimetic superhydrophobic pigments with high contact angles and ultralow sliding angles for various aqueous solutions were fabricated by combining palygorskite, cationic dyes, and organosilanes. Superhydrophobicity of the pigments is closely related to their topography and chemical composition, which can be regulated simply by changing the concentrations of organosilanes. The superhydrophobic pigments feature an excellent self-cleaning property and high stability under various conditions owing to an air cushion at the solid–liquid interface and a shielding effect of the chemically inert coating based on organosilanes. Moreover, durable superhydrophobic pigments of various colours can be easily prepared using different cationic dyes and applied onto various substrates via the same procedure.
Co-reporter:Lingxiao Li, Bucheng Li, Ling Fan, Bin Mu, Aiqin Wang and Junping Zhang
Journal of Materials Chemistry A 2016 vol. 4(Issue 16) pp:5859-5868
Publication Date(Web):25 Feb 2016
DOI:10.1039/C6TA00758A
Superoleophobic coatings and remotely controllable liquid marbles are of great interest in many fields. Here, we report the preparation of magnetic nanocomposites that can be used for the fabrication of superoleophobic coatings and magnetic liquid marbles from both water and organic liquids with surface tension as low as 22.85 mN m−1. The nanocomposites were prepared by growing Fe3O4 nanoparticles on the needle-like crystals of palygorskite (PAL) via modified solvothermal reduction reactions between FeCl3 and ethylene glycol, and then coated by hydrolytic condensation of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) and tetraethoxysilane (TEOS). The nanocomposites were characterized using a wide range of electron microscopy and other analytical techniques. The growth of Fe3O4 nanoparticles on PAL not only provides magnetic responsivity, but also constructs a hierarchical micro/nanostructure. The coatings with tunable wettability and liquid marbles encapsulated with liquids of different surface tensions were obtained simply by controlling the surface topography and surface chemical composition, in other words, the volume ratio of PFDTES to TEOS. The superoleophobic coatings show high contact angles and low sliding angles for various organic liquids such as n-hexadecane, toluene, n-dodecane, etc. The liquid marbles feature excellent magnetic responsivity, high stability and a very thin layer of solid powder.
Co-reporter:Junping Zhang, Bucheng Li, Lingxiao Li and Aiqin Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 6) pp:2069-2074
Publication Date(Web):14 Jan 2016
DOI:10.1039/C5TA10001A
Ultralight, compressible and multifunctional carbon aerogels (UCM aerogels) have broad potential applications in various fields including thermal insulation, oil absorption and electronics. However, the preparation of UCM aerogels has been proven to be very challenging. Herein, we report a novel approach for the fabrication of UCM aerogels by pyrolysis of aerogels composed of kapok fibers (KFs), a kind of natural cellulose with a tubular structure. Different from the frequently used freeze-drying approach, the wet KF aerogels can be dried directly in an oven without any shrinkage. The fascinating UCM aerogels feature ultralow density (∼1.0 mg cm−3), high compressibility, high electrical conductivity (0.1 S cm−1), excellent fire-resistance and very high absorption capacity (147–292 g g−1) for organic liquids. Furthermore, the UCM aerogels can be easily endowed with various other functions, e.g., magnetic responsivity and superhydrophobicity. The successful creation of the UCM aerogels may provide new insights into the design of UCM aerogels for various applications, as the UCM aerogels can be prepared via a very simple procedure.
Co-reporter:Lingxiao Li, Bucheng Li and Junping Zhang
Journal of Materials Chemistry A 2016 vol. 4(Issue 2) pp:512-518
Publication Date(Web):16 Nov 2015
DOI:10.1039/C5TA08829A
Large volume shrinkage and high temperature are frequently encountered problems during the preparation of graphene aerogels via hydrothermal reactions. Here we report the dopamine-mediated fabrication of ultralight graphene aerogels (UGAs) with low volume shrinkage via hydrothermal reactions at low temperature. The UGAs were fabricated by the hydrothermal reaction of the graphene oxide (GO)/dopamine colloidal solutions at 85 °C in the presence of dopamine followed by freeze-drying and pyrolysis. The interaction between GO and dopamine in the aqueous phase, the effects of various parameters on the formation of the UGAs, the roles of dopamine in hydrothermal reactions as well as the wettability and electrical conductivity of the UGAs were investigated using a wide range of analytical techniques. The GO concentration, dopamine concentration, and the temperature and time of the hydrothermal reaction have great influences on the formation of the UGAs. The addition of dopamine forms crosslinking points among the GO sheets and results in the partial reduction of GO in the hydrothermal reaction. In addition, the N atoms of dopamine were doped into the graphene sheets. The UGAs feature low volume shrinkage (8.3%), ultralow density (3.5 mg cm−3), excellent superhydrophobicity/superoleophilicity (CAwater ∼ 155.5° and CAoil ∼ 0°), very high absorbency for organic liquids (134.0–282.9 g g−1) as well as excellent fire retardant properties and high conductivity (3.07 S cm−1). All these merits make the UGAs very promising materials for absorption of organic pollutants, sensors, energy storage, etc.
Co-reporter:Yujie Zhang, Jie Dong, Hanxue Sun, Bo Yu, Zhaoqi Zhu, Junping Zhang, and Aiqin Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 40) pp:27346
Publication Date(Web):September 22, 2016
DOI:10.1021/acsami.6b09252
Organic allochroic materials have wide potential applications in various fields but have so far been limited because of their low stability and low and slow switching reversibility. Because of the extraordinarily high durability of Maya Blue and the superhydrophobic lotus leaves, the new solvatochromic and self-cleaning coatings with intense blue color are fabricated by the combination of polysiloxane-modified palygorskite (PAL@POS) and crystal violet lactone (CVL) via solid-state grinding. The coatings are characterized using scanning electron microscopy, diffusive reflection UV–vis spectra, and other analytical techniques. The hydrogen bonding of the hydroxyl groups of PAL@POS with the carboxylate groups of CVL+ is the origin of the intense blue color. The interruption of the hydrogen bonding by the vapor of solvents results in rapid discoloration of the coating. On the other hand, the evaporation of the solvents from the coating results in complete recovery of the original color by restoring the hydrogen bonding between PAL@POS and CVL+. The polarity, hydrogen bonding ability, and volatility of the solvents determine the solvatochromic properties of the coating. The PAL@POS/CVL coatings feature high reversibility and rapid switching between the colored and colorless states induced by the vapor of various solvents. Also, the coatings are superhydrophobic with fine self-cleaning properties and high durability in different environments. Moreover, the CVL content in the coating is controllable and can be as high as 4.8 wt %.Keywords: attapulgite; silanes; superhydrophobic; surface chemistry; wettability
Co-reporter:Bucheng Li and Junping Zhang
Chemical Communications 2016 vol. 52(Issue 13) pp:2744-2747
Publication Date(Web):05 Jan 2016
DOI:10.1039/C5CC09951J
Durable and self-healing superamphiphobic coatings with high repellency to both cool and hot liquids are successfully prepared on various substrates by the combination of rodlike palygorskite and organosilanes via spray-coating. The coatings feature high mechanical, environmental and chemical durability, and are self-healing.
Co-reporter:Junping Zhang, Lei Wu, Yujie Zhang and Aiqin Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 36) pp:18475-18482
Publication Date(Web):04 Aug 2015
DOI:10.1039/C5TA04839G
Bioinspired materials with special wettability towards water and oils have been proven very efficient in removal of insoluble organic pollutants in water. However, these materials cannot remove water-soluble organic contaminants, and often have some problems such as easy contamination by oils, low water tolerance and complicated preparation methods. Herein, we present a simple approach for the fabrication of mussel and fish scale-inspired underwater superoleophobic kapok membranes via treatment of natural kapok fibers with sodium chlorite, surface modification with polydopamine, and then filtered to yield membranes. SC treatment and PDA modification not only make the membranes underwater superoleophobic with high contact angles and low sliding angles for oils, but also introduce abundant N and O-containing groups. The kapok membranes feature excellent underwater superoleophobicity, high adsorption properties for water-soluble dyes, and high stability and flexibility. Furthermore, continuous and simultaneous removal of many kinds of insoluble oils and soluble dyes in water was achieved with very high removal efficiencies in a short time by simply passing through these membranes. We believe that the underwater superoleophobic kapok membranes are very promising for removal of organic pollutants in water.
Co-reporter:Lei Wu, Lingxiao Li, Bucheng Li, Junping Zhang, and Aiqin Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 8) pp:4936
Publication Date(Web):February 11, 2015
DOI:10.1021/am5091353
Magnetic, durable, and superhydrophobic polyurethane (PU) sponges were fabricated by chemical vapor deposition (CVD) of tetraethoxysilane (TEOS) to bind the Fe3O4 nanoparticles tightly on the sponge and then dip-coating in a fluoropolymer (FP) aqueous solution. The sponges were characterized using scanning electron microscopy and other analytical techniques. The effects of CVD time of TEOS and FP concentration on wettability, mechanical properties, oil absorbency, and oil/water selectivity of the sponges were also investigated. The sponges exhibit fast magnetic responsivity and excellent superhydrophobicity/superoleophilicity (CAwater = 157° and CAoil ≈ 0°). The sponges also show very high efficiency in oil/water separation and could, driven by a magnet, quickly absorb floating oils on the water surface and heavy oils under water. Moreover, the PU@Fe3O4@SiO2@FP sponges could be used as membranes for oil/water separation and for continuous separation of large amounts of oil pollutants from the water surface with the help of a pump. The in turn binding of Fe3O4 nanoparticles, SiO2, and FP can also improve mechanical properties of the PU sponge. The sponges maintain the superhydrophobicity even when they are stretched with 200% strain or compressed with 50% strain. The sponges also show excellent mechanical stability, oil stability, and reusability in terms of superhydrophobicity and oil absorbency. The magnetic, durable, and superhydrophobic PU sponges are very promising materials for practical oil absorption and oil/water separation.Keywords: polyurethane sponges; silica; superoleophilic; surface chemistry; water purification
Co-reporter:Yujie Zhang, Junping Zhang, Aiqin Wang
Journal of Colloid and Interface Science 2015 Volume 457() pp:254-263
Publication Date(Web):1 November 2015
DOI:10.1016/j.jcis.2015.07.030
Highlights•A facile approach for preparing stable palygorskite/methyl violet@SiO2 pigment.•The pigment exhibits excellent stability against chemical attacks.•The new approach may be used for the preparation of eco-friendly Maya Blue-like pigments of various colors.Maya Blue pigment has attracted considerable attention owing to their extraordinary stability. The growing interest in this field has largely expanded the study of Maya Blue-like pigments. Inspired by Maya Blue, a stable palygorskite/methyl violet@SiO2 (PAL/MV@SiO2) “Maya Violet” pigment was fabricated via adsorption of MV by PAL, and then deposition of a layer of SiO2 on the surface by polycondensation of tetraethoxysilane (TEOS) in the presence of cetyltrimethylammonium bromide (CTAB). The weight ratio of MV to PAL is as high as 10%. The pigments were characterized by scanning electron microscopy and a variety of analytical techniques, e.g., Fourier Transform infrared spectroscopy and zeta potential. The results indicate that MV molecules are fixed onto the exterior surface, the grooves and at the entrances of the channels of PAL. The PAL/MV@SiO2 pigment shows excellent stability against chemical attacks, e.g., 0.1 M HCl, 0.1 M NaOH and various organic solvents. Different from Maya Blue, grinding and heating treatment are virtually ineffective in improving stability of the PAL/MV pigment. CTAB and the SiO2 layer formed on the surface of PAL/MV contribute greatly to the improved stability of the pigment due to shielding effect. The optimal CTAB/TEOS/ammonia/H2O molar ratio for the surface modification of PAL/MV is 0.24/1/2.89/495.
Co-reporter:Yujie Zhang, Ling Fan, Hao Chen, Junping Zhang, Yuan Zhang, Aiqin Wang
Microporous and Mesoporous Materials 2015 Volume 211() pp:124-133
Publication Date(Web):15 July 2015
DOI:10.1016/j.micromeso.2015.03.002
•A facile method for preparing stable palygorskite/methylene blue@SiO2 (PAL/MB@SiO2) Maya Blue-like pigments.•The pigment shows excellent stability against elution, thermal aging and UV.•The MB content in the pigments can be as high as 12%.A facile method for the preparation of stable palygorskite/methylene blue@SiO2 (PAL/MB@SiO2) Maya Blue-like pigment was reported. The PAL/MB pigment was prepared via adsorption of MB by PAL, which was further coated with a layer of SiO2 by polycondensation of tetraethoxysilane (TEOS) with acetic acid (HAc) as the catalyst to form the PAL/MB@SiO2 pigment. The weight ratio of MB to PAL, ball milling time and heating temperature play important roles in affecting stability of the PAL/MB pigment. The MB content in the PAL/MB pigment is up to 12%, which is higher than all the state-of-the-art Maya Blue-like pigments. The MB molecules can only be adsorbed onto the external surface, the grooves and the openings of the channels of PAL, but cannot enter the channels according to the BET, zeta potential, FTIR and XRD analyses. Owing to the fact that the stability of the PAL/MB pigment is not very high, a layer of SiO2 is introduced to shield the MB molecules and further improve the stability. The PAL/MB@SiO2 pigment shows excellent stability against elution, thermal aging and intensive UV irradiation. A TEOS/HAc/H2O molar ratio of 1/2/140 in forming the SiO2 layer is greatly helpful to improve the stability.
Co-reporter:Ling Fan;Bucheng Li
Advanced Materials Interfaces 2015 Volume 2( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/admi.201500019
Fouling of surfaces due to bioadhesion is one of the hurdles in terms of their practical applications. Inspired by mussel and lotus leaf, antibioadhesive superhydrophobic syringe needles are fabricated by sequential bonding of polydopamine, Ag nanoparticles, and 1H,1H,2H,2H-perfluorodecanethiol (PFDT). The morphology and surface chemical composition of the needles are characterized. The wetting properties and antibioadhesive properties of the needles are evaluated by contact angle (CA) and sliding angle (SA) of water and various aqueous solutions, and their residues on the needles after repeatedly used for liquid handling. The superhydrophobic needles show a rough surface with a layer of PFDT, which endow them with very high CA and low SA for water and various aqueous solutions. In addition, the aqueous solutions are in the Cassie–Baxter state on the surface of the superhydrophobic needles. Thus, the adhesion force between the superhydrophobic needles and aqueous solutions is very low. This endues the needles with excellent antibioadhesive properties and can be repeatedly used for withdrawing and dispensing various aqueous solutions. Moreover, the superhydrophobic needles can be used for the transport of aqueous solutions at high accuracy. The antibioadhesive superhydrophobic needles may find applications in various fields such as liquids transport and inkjet printing devices.
Co-reporter:Yujie Zhang, Ling Fan, Junping Zhang and Aiqin Wang
RSC Advances 2015 vol. 5(Issue 44) pp:35010-35016
Publication Date(Web):10 Apr 2015
DOI:10.1039/C5RA01863C
Poor water-dispersibility and stability of hydrophobic fluorescent organic pigments (HFOPs) hinder many of their applications. Inspired by the excellent stability of Maya Blue pigments and the water solubility of LAPONITE® RD (LRD), we report the facile synthesis of water-dispersible and stable fluorescent Maya Blue-like pigments via the host–guest interaction between LRD and Pigment Red 31 (PR 31), a representative HFOP. The concentration of LRD and solid-state grinding play important roles in effectively dispersing PR 31 into the aqueous solution. The interactions between PR 31 and LRD involve van der Waals, π–π, electrostatic, hydrogen bonding between phenolic hydroxyl groups of PR 31 and silanols of LRD as well as dye–dye hydrophobic interactions. The interactions between PR 31 and LRD occur on the external surface of LRD and the entrance of the micropores of LRD, however, the PR 31 molecules cannot intercalate into the layers of LRD plates. The so-obtained pigments are highly water-dispersible, and very stable to thermal aging and UV irradiation owing to the interactions between LRD and PR 31, and the shielding effect of LRD.
Co-reporter:Junping Zhang;Aiqin Wang;Stefan Seeger
Advanced Functional Materials 2014 Volume 24( Issue 8) pp:1074-1080
Publication Date(Web):
DOI:10.1002/adfm.201301481
Nepenthes pitcher inspired anti-wetting coatings, fluoro-SNs/Krytox, are successfully fabricated by the combination of fluoro-silicone nanofilaments (fluoro-SNs) and Krytox liquids, perfluoropolyethers. Fluoro-SNs with different microstructure are grown onto glass slides using trichloromethylsilane by simply repeating the coating step, and then modified with 1H,1H,2H,2H-perfluorodecyltrichlorosilane. Subsequently, the Krytox liquid is spread on the fluoro-SNs coatings via capillary effect. The fluoro-SNs/Krytox coatings feature ultra-low sliding angle for various liquids, excellent stability, and transparency. The sliding speed of liquid drops on the fluoro-SNs/Krytox coating is obviously slower than on the lotus inspired superhydrophobic and superoleophobic coatings, and is controlled by composition of the coating (e.g., morphology of the fluoro-SNs, type of Krytox and its thickness) and properties of the liquid drops (e.g., density and surface tension). In addition, the self-cleaning property of the fluoro-SNs/Krytox coating is closely related to properties of liquid drops and dirt.
Co-reporter:Xia Zhao, Lingxiao Li, Bucheng Li, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 43) pp:18281-18287
Publication Date(Web):12 Sep 2014
DOI:10.1039/C4TA04406A
A facile method for preparing porous polydimethylsiloxane (PDMS) sponges is reported. The PDMS sponges are fabricated by the polymerization of the PDMS prepolymer and a curing agent in dimethicone using NaCl microparticles as the hard templates. The porous structure of the PDMS sponges is controllable simply by regulating the weight ratio of prepolymer to dimethicone and the size of the NaCl microparticles. The PDMS sponges feature high compressibility and stretchability, excellent superhydrophobicity/superoleophilicity, as well as high chemical and thermal stability. The PDMS sponge can completely recover its original shape even after 50 cycles of 90% strain. The elongation at breaking the sponge is as high as 97%. The PDMS sponge is superhydrophobic with a water contact angle of 151.5° but can be easily wetted by oils. The sponge also exhibits excellent repellency to corrosive aqueous liquids. The flexibility and superhydrophobicity of the sponge remain unchanged even after keeping in liquid nitrogen or at 250 °C for 24 h. Long-term immersion in various organics has no obvious influence on superhydrophobicity, oil absorbency, or weight of the sponge. The PDMS sponge can selectively absorb a large amount of floating oils on the water surface and heavy oils under the water, and furthermore, is reusable. Moreover, the PDMS sponge swells quickly after the adsorption of oils, which makes it a promising material for plugging oil leakages.
Co-reporter:Bucheng Li, Lei Wu, Lingxiao Li, Stefan Seeger, Junping Zhang, and Aiqin Wang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 14) pp:11581
Publication Date(Web):June 23, 2014
DOI:10.1021/am502313h
Inspired by the mussel adhesive protein and the lotus leaf, Ag-based double-layer polyester (DL-PET) textiles were fabricated for effective removal of organic pollutants in water. The DL-PET textiles are composed of a top superamphiphilic layer and a bottom superhydrophobic/superoleophilic layer. First, the PET textiles were modified with a layer of polydopamine (PDA) and deposited with Ag nanoparticles to form the PET@PDA@Ag textiles. The top superamphiphilic layer, formed by immobilizing Ag3PO4 nanoparticles on the PET@PDA@Ag textile, shows excellent visible-light photocatalytic activity. The bottom superhydrophobic/superoleophilic layer, formed by modifying the PET@PDA@Ag textile using dodecyl mercaptan, is mechanically, environmentally, and chemically very stable. The water-insoluble oils with low surface tension can penetrate both layers of the DL-PET textiles, while the water with soluble organic dyes can only selectively wet the top layer owing to their unique wettability. Consequently, the water-soluble organic contaminants in the collected water can be decomposed by the Ag3PO4 nanoparticles of the top layer under visible-light irradiation or even sunlight in room conditions. Thus, the DL-PET textiles can remove various kinds of organic pollutants in water including both insoluble oils and soluble dyes. The DL-PET textiles feature unique wettability, high oil/water separation efficiency, and visible-light photocatalytic activity.Keywords: Ag; bioinspiration; photocatalysis; superhydrophobic; water purification
Co-reporter:Lingxiao Li, Bucheng Li, Lei Wu, Xia Zhao and Junping Zhang
Chemical Communications 2014 vol. 50(Issue 58) pp:7831-7833
Publication Date(Web):04 Jun 2014
DOI:10.1039/C4CC03045A
Porous silicone sponges are fabricated by polymerization of organosilanes in the presence of Fe3O4@silica nanoparticles. The sponges feature fast magnetic responsivity, superhydrophobicity/superoleophilicity, high compressibility and stability. The sponges can selectively absorb floating oils on a water surface, heavy oils under water and even emulsified oils.
Co-reporter:Lei Wu, Junping Zhang, Bucheng Li and Aiqin Wang
Polymer Chemistry 2014 vol. 5(Issue 7) pp:2382-2390
Publication Date(Web):22 Nov 2013
DOI:10.1039/C3PY01478A
A facile approach for preparing magnetically driven durable superhydrophobic polyester materials is developed by simply dip-coating in a nanocomposite solution. The nanocomposite is prepared by the polymerization of tetraethoxysilane and n-hexadecyltriethoxysilane in the presence of the Fe3O4 nanoparticles. The coated magnetic samples exhibit excellent superhydrophobicity, superoleophilicity, and mechanical and chemical stability, owing to the tight binding of the nanocomposite on the polyester materials and the inherent stability of the polymerized organosilanes. The superhydrophobic materials can quickly absorb petrol, diesel and crude oil, and show very high selectivity in oil/water separation. In addition, the superhydrophobic materials could maintain their superhydrophobicity, oil absorption capacity and oil/water selectivity after a large amount of mechanical damage, 90 days of immersion in oil and ten cycles of absorption–desorption. Moreover, the coated sample can be magnetically driven to the polluted water zone using a magnet. Also, the facile approach can be easily scaled up for producing samples on a large scale, which makes it very promising for practical oil absorption.
Co-reporter:Junping Zhang, Aiqin Wang and Stefan Seeger
Polymer Chemistry 2014 vol. 5(Issue 4) pp:1132-1139
Publication Date(Web):22 Oct 2013
DOI:10.1039/C3PY01293J
Recently, a new group of nanostructures called “silicone nanofilaments (SNs)” were prepared via polymerization of organosilanes with small alkyl groups. Organosilanes with long alkyl groups tend to form self-assembled monolayers and cannot form SNs because of their bulky steric hindrance. Here we report the one-step self-assembly of organosilanes with long alkyl groups into SN coatings at room temperature by using tetraethyl orthosilicate (TEOS) or tetrachlorosilane (TCS) as the molecular spacer. The SNs should grow according to a “limiting growth” mechanism via a “seeding-asymmetric growth-further growth” process. The growth of SNs could be controlled simply by the composition of the precursor and the water concentration (Cwater) in toluene. All the precursors studied can form SNs successfully under proper conditions, indicating universality of this method. The wettability of the SN coatings ranges from hydrophilic to superhydrophobic and even to superamphiphobic. Moreover, these coatings are transparent and can be easily applied onto various substrates besides the glass slide. This facile fabrication of SNs using organosilanes with long alkyl groups will shed light on their application in generating unique nanostructures besides self-assembled monolayers.
Co-reporter:Lei Wu, Junping Zhang, Bucheng Li, Ling Fan, Lingxiao Li, Aiqin Wang
Journal of Colloid and Interface Science 2014 Volume 432() pp:31-42
Publication Date(Web):15 October 2014
DOI:10.1016/j.jcis.2014.06.046
•A facile approach for preparing super durable superhydrophobic materials.•The materials exhibit excellent mechanical and chemical stabilities.•The superhydrophobic materials can be used for effective oil/water separation.The low stability, complicated and expensive fabrication procedures seriously hinder practical applications of superhydrophobic materials. Here we report an extremely simple method for preparing super durable superhydrophobic materials, e.g., textiles and sponges, by dip coating in fluoropolymers (FPs). The morphology, surface chemical composition, mechanical, chemical and environmental stabilities of the superhydrophobic textiles were investigated. The results show how simple the preparation of super durable superhydrophobic textiles can be! The superhydrophobic textiles outperform their natural counterparts and most of the state-of-the-art synthetic superhydrophobic materials in stability. The intensive mechanical abrasion, long time immersion in various liquids and repeated washing have no obvious influence on the superhydrophobicity. Water drops are spherical in shape on the samples and could easily roll off after these harsh stability tests. In addition, this simple dip coating approach is applicable to various synthetic and natural textiles and can be easily scaled up. Furthermore, the results prove that a two-tier roughness is helpful but not essential with regard to the creation of super durable superhydrophobic textiles. The combination of microscale roughness of textiles and materials with very low surface tension is enough to form super durable superhydrophobic textiles. According to the same procedure, superhydrophobic polyurethane sponges can be prepared, which show high oil absorbency, oil/water separation efficiency and stability.Graphical abstract
Co-reporter:Lei Wu, Junping Zhang, Bucheng Li, Aiqin Wang
Journal of Colloid and Interface Science 2014 Volume 413() pp:112-117
Publication Date(Web):1 January 2014
DOI:10.1016/j.jcis.2013.09.028
•A facile approach for preparing durable superhydrophobic polyester materials.•The materials exhibit excellent mechanical and chemical stabilities.•The materials are stable after mechanical damage, 90 days immersion in oils.•This approach can be easily scaled up for producing samples on a large size.The low stability and complicated fabrication procedures seriously hindered practical applications of superhydrophobic materials. Here we present a facile approach for preparing durable superhydrophobic polyester materials by dip-coating in a nanocomposite solution of polymerized tetraethoxysilane and n-hexadecyltriethoxysilane. The coated samples exhibit excellent superhydrophobicity, superoleophilicity, mechanical and chemical stabilities. This is attributed to the tight binding of the nanocomposite on the polyester fibers and the inherent stability of silicone. The coated samples can quickly absorb petrol, diesel and crude oil, and show very high selectivity in oil/water separation. In addition, the coated samples could maintain their superhydrophobicity, oil absorption capacity and oil/water selectivity after harsh mechanical damage, 90 days of immersion in oils and ten cycles of absorption–desorption. Moreover, this approach is simple and can be easily scaled up for producing samples on a large size, which makes it very promising for practical oil absorption.
Co-reporter:Ling Fan;Bucheng Li;Qin Wang;Aiqin Wang
Advanced Materials Interfaces 2014 Volume 1( Issue 5) pp:
Publication Date(Web):
DOI:10.1002/admi.201300136
Inspired by the water repellency of the lotus leaf, superhydrophobic gated nanocontainers are fabricated by using halloysite nanotubes (HNTs) as the nanocontainers and polyorganosilanes (POS) as the molecular gates for sustained release of diclofenac sodium (DS). The nanocontainers are prepared by loading DS into the lumen of HNTs, and then modified by co-condensation of hexadecyltriethoxylsilane and tetraethoxysilane. The nanocontainers are characterized with transmission electron microscopy, energy dispersive X-ray analysis and FTIR, etc. The wetting behaviors of the nanocontainers and release behaviors of DS are also studied. DS molecules are loaded in the lumen of HNTs and POS is covalently bonded on the surface of HNTs-DS. Wettability of the nanocontainers is controllable simply by the POS content. The nanocontainers show excellent superhydrophobicity with a water contact angle of 156.9° and a water shedding angle of 3°. The release of DS molecules is controlled by a new way, the air cushion between the superhydrophobic nanocontainers and the phosphate buffer solution (PBS). The DS molecules could only release from the limited place where the nanocontainers contact with PBS when the PBS is in the Cassie-Baxter state on the surface of the nanocontainers.
Co-reporter:Ling Fan, Yujie Zhang, Junping Zhang and Aiqin Wang
RSC Advances 2014 vol. 4(Issue 108) pp:63485-63493
Publication Date(Web):14 Nov 2014
DOI:10.1039/C4RA13739F
Inspired by Maya Blue, we report the fabrication of stable “Maya Red” pigments with a purple-red hue by adsorption of cationic red X-GRL (CR-X-GRL) onto palygorskite (PAL), which is followed by hydrolysis and polycondensation of tetraethoxysilane (TEOS) via a modified Stöber method to form a layer of SiO2. The parameters influencing the adsorption of CR-X-GRL onto PAL (e.g., mCR-X-GRL/mPAL and the ball milling time) and polycondensation of TEOS (e.g., concentrations of TEOS and ammonia, and volume ratio of ethanol to water) were investigated by using stability of the pigment as the probe. The CR-X-GRL content in the PAL/CR-X-GRL pigments can be as high as 12%, which is higher than all the state-of-the-art Maya Blue-like pigments. Since the stability of the PAL/CR-X-GRL pigments is not very high, a layer of SiO2 was introduced to further improve the stability. The SEM, TEM, FTIR and BET data prove the presence of silica on the surface of the PAL/CR-X-GRL pigment. The PAL/CR-X-GRL@SiO2 “Maya Red” pigments show excellent chemical (1 M HCl, 1 M NaOH and ethanol), thermal and UV stability.
Co-reporter:Junping Zhang, Lei Wu, Bucheng Li, Lingxiao Li, Stefan Seeger, and Aiqin Wang
Langmuir 2014 Volume 30(Issue 47) pp:14292-14299
Publication Date(Web):2017-2-22
DOI:10.1021/la503300k
The newly developed Nepenthes pitcher (NP)-inspired slippery surfaces, formed by immobilizing fluoroliquids on lotus leaf (LL)-inspired superoleophobic surfaces, are of great general interest, whereas there are many interesting phenomena and fundamental scientific issues remaining to be unveiled. Here we present our findings of the effects of evaporation of the fluoroliquid, an inevitable process in most cases, -induced transition from NP-inspired to LL-inspired surfaces on the wettability, transparency, and self-cleaning property of the surfaces. The transition is controlled by regulating the evaporation temperature of the model fluoroliquid, Krytox100. The evaporation of Krytox100 has great a influence on the wettability, transparency, and self-cleaning property. An intermediate “sticky” state is observed in the transition process. We believe that our findings in the transition process are helpful in understanding the similarities and differences between the NP-inspired and LL-inspired surfaces and in designing new bioinspired antiwetting surfaces and exploring their potential applications.
Co-reporter:Bucheng Li;Lingxiao Li;Lei Wu;Aiqin Wang
ChemPlusChem 2014 Volume 79( Issue 6) pp:850-856
Publication Date(Web):
DOI:10.1002/cplu.201300403
Abstract
The low stability of most superhydrophobic materials is one of the hurdles faced in terms of their practical applications. Inspired by mussel and lotus leaf, we report the fabrication of durable superhydrophobic/superoleophilic polyurethane (PU) sponges for the selective removal of organic pollutants from water. The superhydrophobic/superoleophilic PU sponges are prepared through in-turn covalent modification of PU sponges with polydopamine, silver nanoparticles, and dodecyl mercaptan. The morphology and surface chemical composition of the sponges are characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. In addition, the wetting behaviors, stability, and oil/water separation performance of the superhydrophobic sponges are studied. The modified PU sponges show promising superhydrophobic and superoleophilic properties. The sponge has a water contact angle of about 155° and a shedding angle of approximately 3°, whereas the contact angle of oil is around 0°. In addition, the superhydrophobic coating on the PU sponge exhibits excellent mechanical, chemical, and environmental stability, for example, upon laundering, intensive scalpel scratching, long-duration immersion in organic liquids and oils, and subjection to harsh temperatures and UV irradiation. Moreover, the superhydrophobic sponge can be used repeatedly for the selective and quick absorption of various insoluble organic pollutants (for example, petrol, crude oil, and chloroform) from water with high separation efficiency.
Co-reporter:Qin Wang, Junping Zhang, Yue Zheng, Aiqin Wang
Colloids and Surfaces B: Biointerfaces 2014 Volume 113() pp:51-58
Publication Date(Web):1 January 2014
DOI:10.1016/j.colsurfb.2013.08.036
Halloysite nanotube is an ideal vehicle of the controlled release of drugs. In this study, we systematically investigated the effects of acid- and heat-treatments on the physicochemical properties, structure and morphology of halloysite by XRD, FTIR, SEM and TEM. Afterwards, the adsorption and in vitro release properties of halloysite for cationic ofloxacin (OFL) were evaluated. The results indicate that HCl treatment has no influence on the crystal structure of halloysite, whereas it becomes amorphous after calcined at temperature higher than 500 °C. Both acid- and heat-treatments have no evident influence on the tubular structure of halloysite. OFL was adsorbed onto halloysite via electrostatic interaction between protonated OFL and negative halloysite surface, cation exchange as well as electrostatic interaction between the OFL-Al3+ complexes and the negative halloysite surface. Acid-treatment facilitates the release of the adsorbed OFL compared with the natural halloysite in spite of a slight decrease of adsorption capacity. However, heat-treatment results in a sharp decrease of adsorption capacity for OFL owning to the OFL-promoted dissolution of aluminum and the disappearance of the porous structure. Although heat-treatment also facilitates release of the adsorbed OFL, the amount of OFL released is in fact less than the natural halloysite owing to the very low adsorption capacity. Thus, acid-activation is an effective protocol to improve the adsorption and release of halloysite for cationic drug molecules.
Co-reporter:Ling Fan, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 45) pp:6261-6270
Publication Date(Web):18 Sep 2013
DOI:10.1039/C3TB20971G
Diclofenac sodium-loaded sodium alginate/hydroxyapatite/halloysite nanotubes (SA/HA/HNTs–DS) nanocomposite hydrogel beads were prepared by the in situ generation of HA nanoparticles during the sol–gel transition of the SA/HNTs suspension. The nanocomposite beads were characterized by FT-IR spectroscopy, thermogravimetric analysis and field emission scanning electron microscopy, etc. Factors, e.g., the weight ratio of HNTs to SA (mHNTs/mSA), the weight ratio of (NH4)2HPO4 to SA (m(NH4)2HPO4/mSA), and the concentration of SA, which influenced the entrapment efficiency (EE) and release of DS, were investigated. The EE was enhanced from 62.85 ± 0.29% to 74.63 ± 1.65%, and the burst release of DS was overcome by introducing appropriate amounts of HA and HNTs. An almost constant rate release of DS is achieved when mHNTs/mSA = 0.3 and m(NH4)2HPO4/mSA = 0.1. The release rate of DS from the SA/HA/HNTs–DS beads was 9.19 mg g−1 h−1. The release of DS is controlled by Case-II transport. The tubular structure of the HNTs and the in situ-formed HA nanoparticles can restrict movability of the SA polymer chains, which is the main reason for the improved drug loading and release behavior.
Co-reporter:Lei Wu, Junping Zhang, Bucheng Li and Aiqin Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 37) pp:4756-4763
Publication Date(Web):12 Jul 2013
DOI:10.1039/C3TB20934B
Low mechanical stability of superhydrophobic surfaces is the bottle neck we are facing for their practical applications. Here we report facile fabrication of durable superhydrophobic textiles by dip coating in a nanocomposite solution of fluoro-free organosilanes. The kind of organosilane, molar ratio of organosilane in the precursor and water concentration as well as the dip coating parameters (e.g., concentration of nanocomposite, ultrasonication and curing time) have great influences on the superhydrophobicity and abrasion stability of the coated textiles. The superhydrophobic textiles show excellent mechanical, chemical and environmental stability under the optimal conditions. No obvious changes in contact angle can be seen during various stability tests. Water drops stay nearly spherical in shape on the samples and could easily roll off the samples after various stability tests. In addition, the slightly reduced superhydrophobicity can be easily repaired by dip coating again in the same nanocomposite solution. Moreover, this simple approach can be easily applied to various substrates and scaled up. The excellent stability of the superhydrophobic textiles and the simple dip coating procedure pave the way for their practical applications in various fields such as oil/water separation.
Co-reporter:Junping Zhang and Bucheng Li
Journal of Materials Chemistry A 2013 vol. 1(Issue 36) pp:10626-10630
Publication Date(Web):25 Jul 2013
DOI:10.1039/C3TA12284K
Universal dispersion of single-walled carbon nanotubes (SWNTs) in the liquid phase using Laponite RD (LRD) is achieved via a simple grinding–ultrasonication procedure inspired by Maya Blue. The marriage between SWNTs and water-soluble LRD via van der Waals interactions and electron donating–accepting interactions generates a water-dispersible hybrid, which we term LRD/SWNTs. The concentration of LRD and hand-grinding play important roles in effectively dispersing SWNTs. The LRD/SWNT aqueous dispersion features excellent stability (over 6 months without any sediment) and a high SWNT concentration of 1.83 mg mL−1, which is obviously superior to the frequently used surfactants and other materials for noncovalent dispersion of carbon nanotubes. Moreover, the LRD/SWNT aqueous dispersion is miscible with and stable in the other common organic solvents, e.g., methanol, DMF and DMSO.
Co-reporter:Junping Zhang, Bucheng Li, Lei Wu and Aiqin Wang
Chemical Communications 2013 vol. 49(Issue 98) pp:11509-11511
Publication Date(Web):25 Jul 2013
DOI:10.1039/C3CC43238F
This article presents a facile approach for the preparation of durable and robust superhydrophobic textiles by simply dip coating in a nanocomposite solution of fluoro-free organosilanes. The superhydrophobic textiles exhibit good water repellency and excellent mechanical, chemical and environmental stability.
Co-reporter:Qin Wang, Junping Zhang, Aiqin Wang
Applied Surface Science 2013 Volume 287() pp:54-61
Publication Date(Web):15 December 2013
DOI:10.1016/j.apsusc.2013.09.057
Highlights
- •
Alkali activation increases pore volume, pore size distribution of halloysite, and then the adsorption capacity for OFL.
- •
OFL can be adsorbed onto the external surface halloysite via electrostatic interaction or enter into the lumen of halloysite via complexation with amorphous Al(III) in the lumen of halloysite.
- •
Alkali activation can prolong the release of the adsorbed OFL, and was proved to be an effective approach to improve adsorption and release for cationic drugs.
Co-reporter:Qin Wang, Junping Zhang and Aiqin Wang
RSC Advances 2013 vol. 3(Issue 45) pp:23423-23431
Publication Date(Web):02 Oct 2013
DOI:10.1039/C3RA43874K
A series of magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin (CTS/Fe3O4/HNTs/OFL) microspheres was prepared by spray-drying for the sustained release of OFL. CTS was in situ crosslinked by glutaraldehyde in the spray-drying process. The magnetic microspheres were characterized by FT-IR, scanning electron microscopy and thermogravimetric analysis. The magnetic properties, encapsulation efficiency, drug loading and in vitro sustained release properties of the magnetic microspheres for OFL were also evaluated. The CTS/Fe3O4/HNTs/OFL microspheres show superparamagnetic properties and fast magnetic response. The Fe3O4 nanoparticles have a remarkable effect on the surface morphology of the microspheres compared with HNTs. The encapsulation efficiency and the cumulative release are closely related to HNTs and Fe3O4 contents, crosslinking density and CTS concentration. OFL is released from the magnetic CTS/Fe3O4/HNTs/OFL microspheres via anomalous transport.
Co-reporter:Bucheng Li;Dr. Junping Zhang;Lei Wu;Dr. Aiqin Wang
ChemPlusChem 2013 Volume 78( Issue 12) pp:1503-1509
Publication Date(Web):
DOI:10.1002/cplu.201300222
Abstract
Complicated and expensive preparation methods and the low stability of most superhydrophobic surfaces are the bottlenecks that must be faced for their practical application. Herein, a simple and low-cost approach for preparing durable superhydrophobic surfaces by spray coating of polymerized organosilane/attapulgite (POS/APT) nanocomposites is reported. The POS/APT nanocomposites were prepared by condensation of hexadecyltriethoxysilane and tetraethoxysilane in the presence of APT through a modified Stöber method. The morphology and content of clay minerals have great influence on the superhydrophobicity. Only rodlike APT with a weight ratio of APT to organosilanes not less than 0.60 can form the superhydrophobic surfaces. The POS/APT superhydrophobic surfaces feature high water contact angle (CA≈160°), low sliding angle (SA≈2°), excellent stability, and good transparency. A spray coating density as low as 5 g m−2 is enough to obtain the superhydrophobic properties. The cost of such a coating is approximately 4 RMB m−2. The POS/APT surfaces are stable towards sand abrasion, water pressure, harsh temperature, UV irradiation, and solvent immersion. In addition, a slightly damaged surface can be readily repaired by spray coating again according to the same procedure. Moreover, the durable POS/APT superhydrophobic coatings are applicable to various substrates (e.g., polyurethane plate, paper, and polyester textile) and can be easily scaled up.
Co-reporter:Qin Wang, Junping Zhang, Aiqin Wang
Applied Clay Science (January 2014) Volume 87() pp:7-13
Publication Date(Web):January 2014
DOI:10.1016/j.clay.2013.11.017
Co-reporter:Lingxiao Li, Bucheng Li, Jie Dong and Junping Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 36) pp:NaN13725-13725
Publication Date(Web):2016/07/29
DOI:10.1039/C6TA05441B
Inspired by the self-cleaning and water-repellent properties of plants and animals in the natural world, superhydrophobic and superoleophobic materials develop quickly, and are of great interest in academic and industrial areas. Although various chemicals have been used, silanes and silicones play very important roles in the preparation of superhydrophobic and superoleophobic materials. Approximately 25% of the literature about superhydrophobic and superoleophobic materials is based on silanes and silicones. Thus, we believe that an exhaustive literature review from the viewpoint of silane and silicone chemistry is now pertinent to give an overview of the recent progress about their roles in the preparation of superhydrophobic and superoleophobic materials. First of all, we hope to overview the roles of silanes and silicones in constructing micro-/nanostructures, decreasing the surface energy and/or as binders for the fabrication of superhydrophobic and superoleophobic surfaces. We will then focus on the roles of silanes and silicones in the formation of superhydrophobic and superoleophobic particles, sponges and aerogels. In the conclusions, we will summarize the roles of silanes and silicones in forming superhydrophobic and superoleophobic materials, and the challenges in the field. Overall, this review will hopefully help readers to use silanes and silicones dexterously in the design of novel superhydrophobic and superoleophobic materials.
Co-reporter:Lingxiao Li, Bucheng Li, Lei Wu, Xia Zhao and Junping Zhang
Chemical Communications 2014 - vol. 50(Issue 58) pp:NaN7833-7833
Publication Date(Web):2014/06/04
DOI:10.1039/C4CC03045A
Porous silicone sponges are fabricated by polymerization of organosilanes in the presence of Fe3O4@silica nanoparticles. The sponges feature fast magnetic responsivity, superhydrophobicity/superoleophilicity, high compressibility and stability. The sponges can selectively absorb floating oils on a water surface, heavy oils under water and even emulsified oils.
Co-reporter:Junping Zhang, Bucheng Li, Lei Wu and Aiqin Wang
Chemical Communications 2013 - vol. 49(Issue 98) pp:NaN11511-11511
Publication Date(Web):2013/07/25
DOI:10.1039/C3CC43238F
This article presents a facile approach for the preparation of durable and robust superhydrophobic textiles by simply dip coating in a nanocomposite solution of fluoro-free organosilanes. The superhydrophobic textiles exhibit good water repellency and excellent mechanical, chemical and environmental stability.
Co-reporter:Junping Zhang, Bucheng Li, Lingxiao Li and Aiqin Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 6) pp:NaN2074-2074
Publication Date(Web):2016/01/14
DOI:10.1039/C5TA10001A
Ultralight, compressible and multifunctional carbon aerogels (UCM aerogels) have broad potential applications in various fields including thermal insulation, oil absorption and electronics. However, the preparation of UCM aerogels has been proven to be very challenging. Herein, we report a novel approach for the fabrication of UCM aerogels by pyrolysis of aerogels composed of kapok fibers (KFs), a kind of natural cellulose with a tubular structure. Different from the frequently used freeze-drying approach, the wet KF aerogels can be dried directly in an oven without any shrinkage. The fascinating UCM aerogels feature ultralow density (∼1.0 mg cm−3), high compressibility, high electrical conductivity (0.1 S cm−1), excellent fire-resistance and very high absorption capacity (147–292 g g−1) for organic liquids. Furthermore, the UCM aerogels can be easily endowed with various other functions, e.g., magnetic responsivity and superhydrophobicity. The successful creation of the UCM aerogels may provide new insights into the design of UCM aerogels for various applications, as the UCM aerogels can be prepared via a very simple procedure.
Co-reporter:Lingxiao Li, Bucheng Li, Ling Fan, Bin Mu, Aiqin Wang and Junping Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 16) pp:NaN5868-5868
Publication Date(Web):2016/02/25
DOI:10.1039/C6TA00758A
Superoleophobic coatings and remotely controllable liquid marbles are of great interest in many fields. Here, we report the preparation of magnetic nanocomposites that can be used for the fabrication of superoleophobic coatings and magnetic liquid marbles from both water and organic liquids with surface tension as low as 22.85 mN m−1. The nanocomposites were prepared by growing Fe3O4 nanoparticles on the needle-like crystals of palygorskite (PAL) via modified solvothermal reduction reactions between FeCl3 and ethylene glycol, and then coated by hydrolytic condensation of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) and tetraethoxysilane (TEOS). The nanocomposites were characterized using a wide range of electron microscopy and other analytical techniques. The growth of Fe3O4 nanoparticles on PAL not only provides magnetic responsivity, but also constructs a hierarchical micro/nanostructure. The coatings with tunable wettability and liquid marbles encapsulated with liquids of different surface tensions were obtained simply by controlling the surface topography and surface chemical composition, in other words, the volume ratio of PFDTES to TEOS. The superoleophobic coatings show high contact angles and low sliding angles for various organic liquids such as n-hexadecane, toluene, n-dodecane, etc. The liquid marbles feature excellent magnetic responsivity, high stability and a very thin layer of solid powder.
Co-reporter:Ling Fan, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 45) pp:NaN6270-6270
Publication Date(Web):2013/09/18
DOI:10.1039/C3TB20971G
Diclofenac sodium-loaded sodium alginate/hydroxyapatite/halloysite nanotubes (SA/HA/HNTs–DS) nanocomposite hydrogel beads were prepared by the in situ generation of HA nanoparticles during the sol–gel transition of the SA/HNTs suspension. The nanocomposite beads were characterized by FT-IR spectroscopy, thermogravimetric analysis and field emission scanning electron microscopy, etc. Factors, e.g., the weight ratio of HNTs to SA (mHNTs/mSA), the weight ratio of (NH4)2HPO4 to SA (m(NH4)2HPO4/mSA), and the concentration of SA, which influenced the entrapment efficiency (EE) and release of DS, were investigated. The EE was enhanced from 62.85 ± 0.29% to 74.63 ± 1.65%, and the burst release of DS was overcome by introducing appropriate amounts of HA and HNTs. An almost constant rate release of DS is achieved when mHNTs/mSA = 0.3 and m(NH4)2HPO4/mSA = 0.1. The release rate of DS from the SA/HA/HNTs–DS beads was 9.19 mg g−1 h−1. The release of DS is controlled by Case-II transport. The tubular structure of the HNTs and the in situ-formed HA nanoparticles can restrict movability of the SA polymer chains, which is the main reason for the improved drug loading and release behavior.
Co-reporter:Lei Wu, Junping Zhang, Bucheng Li and Aiqin Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 37) pp:NaN4763-4763
Publication Date(Web):2013/07/12
DOI:10.1039/C3TB20934B
Low mechanical stability of superhydrophobic surfaces is the bottle neck we are facing for their practical applications. Here we report facile fabrication of durable superhydrophobic textiles by dip coating in a nanocomposite solution of fluoro-free organosilanes. The kind of organosilane, molar ratio of organosilane in the precursor and water concentration as well as the dip coating parameters (e.g., concentration of nanocomposite, ultrasonication and curing time) have great influences on the superhydrophobicity and abrasion stability of the coated textiles. The superhydrophobic textiles show excellent mechanical, chemical and environmental stability under the optimal conditions. No obvious changes in contact angle can be seen during various stability tests. Water drops stay nearly spherical in shape on the samples and could easily roll off the samples after various stability tests. In addition, the slightly reduced superhydrophobicity can be easily repaired by dip coating again in the same nanocomposite solution. Moreover, this simple approach can be easily applied to various substrates and scaled up. The excellent stability of the superhydrophobic textiles and the simple dip coating procedure pave the way for their practical applications in various fields such as oil/water separation.
Co-reporter:Junping Zhang and Bucheng Li
Journal of Materials Chemistry A 2013 - vol. 1(Issue 36) pp:NaN10630-10630
Publication Date(Web):2013/07/25
DOI:10.1039/C3TA12284K
Universal dispersion of single-walled carbon nanotubes (SWNTs) in the liquid phase using Laponite RD (LRD) is achieved via a simple grinding–ultrasonication procedure inspired by Maya Blue. The marriage between SWNTs and water-soluble LRD via van der Waals interactions and electron donating–accepting interactions generates a water-dispersible hybrid, which we term LRD/SWNTs. The concentration of LRD and hand-grinding play important roles in effectively dispersing SWNTs. The LRD/SWNT aqueous dispersion features excellent stability (over 6 months without any sediment) and a high SWNT concentration of 1.83 mg mL−1, which is obviously superior to the frequently used surfactants and other materials for noncovalent dispersion of carbon nanotubes. Moreover, the LRD/SWNT aqueous dispersion is miscible with and stable in the other common organic solvents, e.g., methanol, DMF and DMSO.
Co-reporter:Xia Zhao, Lingxiao Li, Bucheng Li, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 43) pp:NaN18287-18287
Publication Date(Web):2014/09/12
DOI:10.1039/C4TA04406A
A facile method for preparing porous polydimethylsiloxane (PDMS) sponges is reported. The PDMS sponges are fabricated by the polymerization of the PDMS prepolymer and a curing agent in dimethicone using NaCl microparticles as the hard templates. The porous structure of the PDMS sponges is controllable simply by regulating the weight ratio of prepolymer to dimethicone and the size of the NaCl microparticles. The PDMS sponges feature high compressibility and stretchability, excellent superhydrophobicity/superoleophilicity, as well as high chemical and thermal stability. The PDMS sponge can completely recover its original shape even after 50 cycles of 90% strain. The elongation at breaking the sponge is as high as 97%. The PDMS sponge is superhydrophobic with a water contact angle of 151.5° but can be easily wetted by oils. The sponge also exhibits excellent repellency to corrosive aqueous liquids. The flexibility and superhydrophobicity of the sponge remain unchanged even after keeping in liquid nitrogen or at 250 °C for 24 h. Long-term immersion in various organics has no obvious influence on superhydrophobicity, oil absorbency, or weight of the sponge. The PDMS sponge can selectively absorb a large amount of floating oils on the water surface and heavy oils under the water, and furthermore, is reusable. Moreover, the PDMS sponge swells quickly after the adsorption of oils, which makes it a promising material for plugging oil leakages.
Co-reporter:Junping Zhang, Lei Wu, Yujie Zhang and Aiqin Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 36) pp:NaN18482-18482
Publication Date(Web):2015/08/04
DOI:10.1039/C5TA04839G
Bioinspired materials with special wettability towards water and oils have been proven very efficient in removal of insoluble organic pollutants in water. However, these materials cannot remove water-soluble organic contaminants, and often have some problems such as easy contamination by oils, low water tolerance and complicated preparation methods. Herein, we present a simple approach for the fabrication of mussel and fish scale-inspired underwater superoleophobic kapok membranes via treatment of natural kapok fibers with sodium chlorite, surface modification with polydopamine, and then filtered to yield membranes. SC treatment and PDA modification not only make the membranes underwater superoleophobic with high contact angles and low sliding angles for oils, but also introduce abundant N and O-containing groups. The kapok membranes feature excellent underwater superoleophobicity, high adsorption properties for water-soluble dyes, and high stability and flexibility. Furthermore, continuous and simultaneous removal of many kinds of insoluble oils and soluble dyes in water was achieved with very high removal efficiencies in a short time by simply passing through these membranes. We believe that the underwater superoleophobic kapok membranes are very promising for removal of organic pollutants in water.
Co-reporter:Yujie Zhang, Junping Zhang and Aiqin Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 3) pp:NaN907-907
Publication Date(Web):2015/12/03
DOI:10.1039/C5TA09300G
The inferior stability of most Maya blue-like pigments to ancient Maya blue seriously hinders their practical applications. Inspired by self-cleaning and water-repellent properties of the lotus leaf in the natural world, biomimetic superhydrophobic pigments with high contact angles and ultralow sliding angles for various aqueous solutions were fabricated by combining palygorskite, cationic dyes, and organosilanes. Superhydrophobicity of the pigments is closely related to their topography and chemical composition, which can be regulated simply by changing the concentrations of organosilanes. The superhydrophobic pigments feature an excellent self-cleaning property and high stability under various conditions owing to an air cushion at the solid–liquid interface and a shielding effect of the chemically inert coating based on organosilanes. Moreover, durable superhydrophobic pigments of various colours can be easily prepared using different cationic dyes and applied onto various substrates via the same procedure.
Co-reporter:Lingxiao Li, Bucheng Li and Junping Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 2) pp:NaN518-518
Publication Date(Web):2015/11/16
DOI:10.1039/C5TA08829A
Large volume shrinkage and high temperature are frequently encountered problems during the preparation of graphene aerogels via hydrothermal reactions. Here we report the dopamine-mediated fabrication of ultralight graphene aerogels (UGAs) with low volume shrinkage via hydrothermal reactions at low temperature. The UGAs were fabricated by the hydrothermal reaction of the graphene oxide (GO)/dopamine colloidal solutions at 85 °C in the presence of dopamine followed by freeze-drying and pyrolysis. The interaction between GO and dopamine in the aqueous phase, the effects of various parameters on the formation of the UGAs, the roles of dopamine in hydrothermal reactions as well as the wettability and electrical conductivity of the UGAs were investigated using a wide range of analytical techniques. The GO concentration, dopamine concentration, and the temperature and time of the hydrothermal reaction have great influences on the formation of the UGAs. The addition of dopamine forms crosslinking points among the GO sheets and results in the partial reduction of GO in the hydrothermal reaction. In addition, the N atoms of dopamine were doped into the graphene sheets. The UGAs feature low volume shrinkage (8.3%), ultralow density (3.5 mg cm−3), excellent superhydrophobicity/superoleophilicity (CAwater ∼ 155.5° and CAoil ∼ 0°), very high absorbency for organic liquids (134.0–282.9 g g−1) as well as excellent fire retardant properties and high conductivity (3.07 S cm−1). All these merits make the UGAs very promising materials for absorption of organic pollutants, sensors, energy storage, etc.
Co-reporter:Bucheng Li, Junping Zhang, Ziqian Gao and Qingyun Wei
Journal of Materials Chemistry A 2016 - vol. 4(Issue 3) pp:NaN960-960
Publication Date(Web):2015/12/07
DOI:10.1039/C5TA08733C
Semitransparent superoleophobic coatings with low sliding angles for hot liquids are successfully prepared by fabrication of silica nanotubes (SNTs) on glass slides, and then modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane. The SNT layers are formed by spray-coating a homogeneous dispersion of polydimethylsiloxane (PDMS)-modified multiwalled carbon nanotubes (MWCNTs) onto glass slides followed by calcination to remove MWCNTs, the templates. The successful fabrication of SNTs and the superoleophobic coatings are confirmed by scanning electron microscopy, transmitting electron microscopy, X-ray photoelectron spectroscopy and investigation of the wetting behavior of n-decane on the coatings, etc. The microstructures of the SNT layers have great influence on superoleophobicity of the coatings, which are controllable by simply regulating the diameter of MWCNTs and the concentrations of MWCNTs and PDMS. The superoleophobic coatings feature high contact angles and low sliding angles for various liquids (such as water, toluene, n-hexadecane, n-decane, etc.), excellent superoleophobicity for hot liquids and good transparency.
Co-reporter:Bucheng Li and Junping Zhang
Chemical Communications 2016 - vol. 52(Issue 13) pp:NaN2747-2747
Publication Date(Web):2016/01/05
DOI:10.1039/C5CC09951J
Durable and self-healing superamphiphobic coatings with high repellency to both cool and hot liquids are successfully prepared on various substrates by the combination of rodlike palygorskite and organosilanes via spray-coating. The coatings feature high mechanical, environmental and chemical durability, and are self-healing.
Co-reporter:Lingxiao Li, Bucheng Li, Hanxue Sun and Junping Zhang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 28) pp:NaN14864-14864
Publication Date(Web):2017/06/20
DOI:10.1039/C7TA03511J
Carbon aerogels are receiving great attention in academia and industry; however, the preparation of high performance carbon aerogels is challenging. Here, we report the preparation of compressible and conductive carbon aerogels (3C aerogels) from waste paper using a general “oxidation-oven drying-carbonization” method. The 3C aerogels are lightweight (23.6 mg cm−3) and show good electrical conductivity (0.051 S cm−1), high compressibility, superhydrophobicity/superoleophilicity and high oil absorption capacity (33–70 g g−1). The 3C aerogels can also be used for the removal of free oils in water via different approaches. Moreover, the 3C aerogels can be used for efficient gravity-driven separation of surfactant-stabilized water-in-oil emulsions and simultaneous adsorption of soluble organic pollutants in the emulsions, both in the water phase and in the oil phase. The 3C aerogels may also find applications in other fields including sensors and pressure-sensitive electronics. This work opens a new avenue for designing carbon aerogels with exceptional performance for oil/water separation.
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