Co-reporter:Fei Lu;Chao Zhang;Bitao Lu;Kun Yu;Jiawei Liu;Hongliang Kang
Cellulose 2017 Volume 24( Issue 4) pp:1621-1629
Publication Date(Web):2017 April
DOI:10.1007/s10570-017-1213-1
To investigate the solvent/solute interactions that take place during the dissolution of cellulose, cellobiose was employed as a model of the longer-chain cellulose molecule in a dissolution study of the cellobiose/LiCl/N-methyl-2-pyrrolidone (NMP) system, conducted using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), 13C, 35Cl, and 7Li NMR spectroscopy, and conductivity measurements. For the LiCl/NMP system, FTIR and 13C NMR analyses of the NMP carbonyl moiety showed a strong dependence on the LiCl concentration, which suggested an association between the Li+ cations and the carbonyl groups of NMP. As the cellobiose molecules are dissolved in the LiCl/NMP solvent, the Li+–Cl− ion-pairs in LiCl/NMP are dissociated. Strong hydrogen bonds are then formed between the hydroxyl groups of cellobiose and the Cl− anions, resulting in breakage of the intermolecular hydrogen bonds of cellobiose. Meanwhile, the Li+ cations are further associated with the extra free NMP molecules. However, the NMP molecules do not directly interact with the dissolved cellobiose. Based on these results, we propose that our study is conducive to a more in-depth comprehension of the dissolution mechanism of cellulose in LiCl/NMP.
Co-reporter:Congxian Zhao, Chao Zhang, Hongliang Kang, Yanzhi Xia, Kunyan Sui, Ruigang Liu
Carbohydrate Polymers 2017 Volume 169(Volume 169) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.carbpol.2017.03.099
•The gelation process of SA was investigated by using NMR relaxometry and PFG NMR diffusometry.•Dynamics of the Na+ in Na-alginate aqueous solution was investigated.•The distribution of the spin–spin relaxation time of Na nuclei identified the Na+ ions in different state.•The diffusion coefficient of Na+ ions increased with the crosslinking density.Sodium alginate (SA) hydrogels have a wide range of applications including tissue engineering, drug delivery and formulations for preventing gastric reflux. The dynamics of sodium ions during the gelation process of SA solution is critical for clarification of the gelation procedure. In this work, nuclear magnetic resonance (NMR) relaxometry and pulsed-field-gradient (PFG) NMR diffusometry were used to investigate the dynamics of the sodium ions during the gelation of SA alginate. We find that sodium ions are in two different states with the addition of divalent calcium ions, corresponding to Ca2+ crosslinked and un-crosslinked regions in the hydrogels. The sodium ions within the un-crosslinked regions are those released from the alginate chains without Ca2+ crosslinking. The relative content of sodium ions within the Ca2+ crosslinked regions decreased with the increase in the content of calcium ions in the system. The relaxation time T2 of sodium ions within the Ca2+ crosslinked and un-crosslinked regions shift to shorter and longer relaxation time with the increase in concentration of calcium ion, which indicates the closer package of SA chains and the larger space for the diffusion of free sodium ions. This work clarifies the dynamics of 23Na+ in a calcium alginate gel at the equilibrium state.
Co-reporter:
Journal of Applied Polymer Science 2017 Volume 134(Issue 15) pp:
Publication Date(Web):2017/04/15
DOI:10.1002/app.44687
ABSTRACTThe process of electrospinning can be affected by various parameters, leading to as-prepared nanofibers with different morphology and properties. In order to explore the impact of DC(+) high-voltage position on the resultant nanofibers, two setups with DC(+) high-voltage individually tethered to the needle (S-1) and the collecting plate (S-2) were fabricated. Nanofibers produced by both setups under the same conditions were examined to distinguish their differences in morphology and electrostatic properties. It was found that the nanofibers with positive surface potential produced by the S-1 setup have a larger surface coverage and porosity, smaller average diameter, and wider distribution of diameters. Furthermore, the differences between both setups in the trajectory of flying jets and the distribution of electric field intensity were studied. The results showed that the volume charge density (VCD) of the flying jets plays a crucial role in determining the morphology and electrostatic properties of the resultant nanofibers. The relationship between the position of DC(+) high-voltage and the VCD of flying jets was then discussed, which could develop a better understanding of the process of electrospinning and deliver more accurate control over the production of various functional nanofibers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44687.
Co-reporter:Wei-wei Li;Hong-liang Kang;Jian Xu 徐坚
Chinese Journal of Polymer Science 2017 Volume 35( Issue 6) pp:764-772
Publication Date(Web):23 April 2017
DOI:10.1007/s10118-017-1922-9
The microcrystalline structure and microvoid structure in carbon fibers during graphitization process (2300−2700 °C) were characterized employing laser micro-Raman scattering (Raman), X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and high-resolution transmission electron microscopy (HR-TEM). The crystalline sizes (La, Lc) increased and interlayer spacing (d002) decreased with increasing heat treatment temperature (HTT). The microvoids in the fibers grew up and contacted to the neighbors with the development of microcrystalline. In addition, the preferred orientation of graphite crystallite along fiber axis decreased and microvoids increased. The results are crucial for analyzing the evolution of microstructure of carbon fibers in the process of heat treatment and important for the preparation of high strength and high modulus carbon fibers.
Co-reporter:Hongliang Kang;Yong Huang
Macromolecular Chemistry and Physics 2016 Volume 217( Issue 12) pp:1322-1334
Publication Date(Web):
DOI:10.1002/macp.201500493
Co-reporter:Chao Zhang, Pingping Li, Yijin Zhang, Fei Lu, Weiwei Li, Hongliang Kang, Jun-feng Xiang, Yong Huang, Ruigang Liu
Polymer 2016 Volume 98() pp:237-243
Publication Date(Web):19 August 2016
DOI:10.1016/j.polymer.2016.06.036
•NMR relaxometry was used for characterization of the porous structure of cellulose.•The hierarchical porous structure of cellulose was not modified during sample preparation and measurement.•The distribution of the porous structure in cellulose samples was obtained by using the NMR relaxometry data.Hierarchical porous structures in cellulose materials are important for the dissolution, properties and applications of cellulose materials. Methods for characterizing the hierarchical porous structures in cellulose materials without changing its original state are still limited. In this work, we introduced nuclear magnetic resonance (NMR) relaxometry for characterizing the hierarchical porous structures in cotton fibers without modifying their structure during sample preparation. By this method, the changes of the porous structures in cotton samples were characterized. It was found that soaking cellulose in water and stewing cellulose in N,N-dimethylacetamide at high temperature could efficiently improve the accessibility of cellulose samples to the solvent molecules and expand the Amorphous Region in cellulose. The method provided in this work can be used for the evaluation of the hierarchical porous structures of cellulose materials without additional modified information, which is helpful to the utilization of cellulose in various fields.Soaking cellulose in water can efficiently improve the accessibility of cellulose materials to the solvent molecules by expanding the Amorphous Region and the Inter-Microfiber Spaces in cellulose materials.
Co-reporter:Chao Zhang;Hongliang Kang;Pingping Li;Zhijing Liu;Yijin Zhang
Cellulose 2016 Volume 23( Issue 2) pp:1165-1175
Publication Date(Web):2016 April
DOI:10.1007/s10570-016-0876-3
Polar aprotic solvents are considered to act as cosolvents with ionic liquids (ILs) for cellulose, strengthening the solvating ability of ILs by improving their cellulose solvating kinetics without influencing the solubility of cellulose in ILs. In this work, it was found that dimethylsulfoxide (DMSO) at low concentration improves the cellulose solvating ability of [AMIM][Cl], but weakens it at high concentration. To clarify the mechanism of these dual effects of DMSO on the cellulose solvating ability of [AMIM][Cl], the [AMIM][Cl]/DMSO system was investigated using excess infrared spectroscopy, nuclear magnetic resonance (NMR) T2 relaxometry, 1H NMR, 35Cl NMR, and dynamic light scattering. The results indicate that the tight association between the cation and anion in the [AMIM][Cl] network is loosened at low DMSO concentration. As a result, mass transport is accelerated due to the enhanced dynamics of [AMIM][Cl], promoting the cellulose solvating kinetics of [AMIM][Cl]. However, ion clusters of [AMIM][Cl] start to form when the molar fraction of DMSO (xDMSO) exceeds 0.5. The hydrogen bonds between cations and anions in the ion clusters become much stronger than in pure [AMIM][Cl], leading to decreased ability of [AMIM][Cl] to form hydrogen bonds with cellulose and thus decreased cellulose solubility in the [AMIM][Cl]/DMSO mixture.
Co-reporter:Zhijing Liu;Chao Zhang;Wushou Zhang;Hongliang Kang
Cellulose 2016 Volume 23( Issue 1) pp:295-305
Publication Date(Web):2016 February
DOI:10.1007/s10570-015-0827-4
The effects of chloride salts on the dissolution of cellobiose in aqueous solution were investigated using calorimetry and 1H NMR. The dissolution of cellobiose in salt solutions is a typical entropy-driven process. The activity of ZnCl2 and LiCl hydrated ions is enhanced as the hydration number decreases with increasing temperature. Zn2+ and Li+ hydrates can interact with the oxygen atoms at the O5 and O6 positions of cellobiose and associate with the Cl− anions, leading to the breakage of cellobiose hydrogen bonds. We found that the solubility of cellobiose in aqueous solutions is on the order of ZnCl2 > LiCl > NaCl > H2O > KCl > NH4Cl, which is consistent with the Hofmeister series. For the first time, we recognized the specific ionic effects of the Hofmeister series on the dissolution of cellobiose in salt aqueous solutions. This finding is helpful for understanding the dissolving mechanism of cellulose in aqueous solvents with salts and providing fundamental knowledge for finding and designing new cellulose solvents.
Co-reporter:Fei Lu;Chao Zhang;Hongliang Kang;Yong Huang
Cellulose 2016 Volume 23( Issue 5) pp:2877-2885
Publication Date(Web):2016 October
DOI:10.1007/s10570-016-1002-2
The extensional flow behaviors of cellulose/NaOH/urea/H2O solution were investigated by using capillary breakup extensional rheometry (CaBER). The effects of temperature, storage time and cellulose concentrations on both the storage modulus G′ and the loss modulus G″ were also analyzed. For 2 wt% cellulose solution, the G′, G″ and filament lifetime remained unchanged after long storage time. While, for 4 wt% cellulose solution, physical gels could form at either higher temperature or for longer storage time, and the filament lifetime, the relaxation time (λe) and the initial extensional viscosity (ηe0) first increased and then decreased with increase of the storage time. The transition points of the filament lifetime shifted to lower storage time with the increase of the temperature. The ηe0 is proportional to λe. The results presented suggest that the extensional properties of the cellulose/NaOH/urea/H2O solution first increase and then decrease during the gelation process, and the spinning time, which decreases linearly with the increase in the storage temperature, must be controlled below the time that ηe0 starts to decrease.
Co-reporter:Meiyan Chen, Hongliang Kang, Yumei Gong, Jing Guo, Hong Zhang, and Ruigang Liu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 39) pp:21717
Publication Date(Web):September 11, 2015
DOI:10.1021/acsami.5b07150
Amidoxime surface functionalized bacterial cellulose (AOBC) has been successfully prepared by a simple two-step method without obviously changing the morphology of bacterial cellulose. AOBC has been used as the reducing agent and carrier for the synthesis of gold nanoparticles (AuNPs) that distributed homogeneously on bacterial cellulose surface. Higher content in amidoxime groups in AOBC is beneficial for the synthesis of AuNPs with smaller and more uniform size. The AuNPs/AOBC nanohybrids have excellent catalytic activity for reduction of 4-nitrophenol (4-NP) by using NaBH4. It was found that catalytic activity of AuNPs/AOBC first increases with increasing NaBH4 concentration and temperature, and then leveled off at NaBH4 concentration above 238 mM and temperature above 50 °C. Moreover, AuNPs with smaller size have higher catalytic activity. The highest apparent turnover frequency of AuNPs/AOBC is 1190 h–1. The high catalytic activity is due to the high affinity of 4-NP with AuNPs/AOBC and the reduced product 4-aminophenol has good solubility in water in the presence of AuNPs/AOBC. The catalytic stability of the AuNPs/AOBC was estimated by filling a fluid column contained AuNPs/AOBC and used for continuously catalysis of the reduction of 4-NP by using NaBH4. The column works well without detection of 4-NP in the eluent after running for more than two months, and it is still running. This work provides an excellent catalyst based on bacterial cellulose stabilized AuNPs and has promising applications in industry.Keywords: amidoxime; bacterial cellulose; catalysis; gold nanoparticles; nanohybrids; reducing reaction; surface modification
Co-reporter:Qinmei Li, Saina Yang, Lijun Zhu, Hongliang Kang, Xiaozhong Qu, Ruigang Liu and Yong Huang
Polymer Chemistry 2015 vol. 6(Issue 15) pp:2869-2878
Publication Date(Web):13 Feb 2015
DOI:10.1039/C4PY01750A
Keratin graft poly(N-(2-hydroxypropyl)methacrylamide) (K-g-PHPMA) copolymers were synthesized and characterized. On account of the thiol groups of keratin and the amphiphilicity of the graft copolymers, micelles with cleavable cross-links on a keratin core were fabricated in water. The K-g-PHPMA micelles can efficiently encapsulate doxorubicin (DOX) and can be used as a drug carrier. The DOX content in the micelles increases with the keratin content of the graft copolymers. The release of the encapsulated DOX in the micelles is sensitive to the physiological environment. Redox trigger glutathione (GSH), especially at the intracellular level, and trypsin can effectively trigger the release of the encapsulated DOX. In vitro cellular uptake experiments indicate that the DOX released from the DOX-loaded K-g-PHPMA micelles can be efficiently internalized into cells. Under higher GSH condition, the DOX shows a much faster release into the nucleus of the cells. The K-g-PHPMA copolymers have promising applications as drug carriers for enhanced intracellular drug delivery in cancer therapy.
Co-reporter:Pingping Li;Hongliang Kang;Ning Che;Zhijing Liu;Chao Zhang;Chun Cao;Weiwei Li;Yong Huang
Polymer International 2015 Volume 64( Issue 8) pp:1015-1022
Publication Date(Web):
DOI:10.1002/pi.4879
Abstract
Well-defined amphiphilic graft copolymers, hydroxypropylcellulose-graft-poly(2-acryloyloxyethyl ferrocenecarboxylate) (HPC-g-PAEFC), were synthesized via atom transfer radical polymerization. The graft copolymers contain hydrophilic thermo-responsive HPC backbones and hydrophobic redox-sensitive PAEFC side chains and can self-assemble into spherical micelles in aqueous solution, with a hydrodynamic radius <Rh > in the range 70–130 nm depending on length of the graft chains. The thermo-responsive properties of the HPC-g-PAEFC copolymers in aqueous solution are gradually destroyed with increasing length of PAEFC side chains. The redox-responsive behaviors of the graft copolymers were investigated with H2O2 and sodium ascorbate as oxidant and reductant, respectively, indicating an incompletely reversible redox-triggered size transition. And the reversibility of the redox process becomes weaker gradually as the side chains are more difficult to be oxidized with an increase of the graft chains, which is evidenced from cyclic voltammetry measurements. The resultant HPC-g-PAEFC graft copolymers with the unique properties of ferrocene and cellulose provide prerequisites for amperometric biosensors and redox-responsive drug delivery carriers. © 2015 Society of Chemical Industry
Co-reporter:Zhijing Liu;Chao Zhang;Wushou Zhang;Hongliang Kang;Ning Che
Cellulose 2015 Volume 22( Issue 3) pp:1641-1652
Publication Date(Web):2015 June
DOI:10.1007/s10570-015-0627-x
Cellobiose was used as a model compound for cellulose to study dissolution in aqueous systems with additives. The dissolution of cellobiose in alkali solutions is a typical exothermic enthalpy-driven process, confirming that lower temperature is beneficial for dissolution of cellulose in NaOH aqueous systems. OH− plays an important role in cellobiose dissolution by forming cellobiose–OH− hydrogen-bonded complexes. The ability to form hydrogen bonds between additives and cellobiose in aqueous solutions follows the order NaOH/urea/ZnO > NaOH/urea/NaAlO2 > NaOH/urea > NaOH. Direct interactions between OH−, amino groups of urea, Na+ hydrates, and cellobiose result in stable hydrogen-bonding complexes among cellobiose, OH−, Na+ hydrates, and urea. Addition of ZnO or NaAlO2 can promote the dissolution power of the solvent system for cellulose. This work clarifies the interactions and dissolution mechanisms of cellulose in aqueous solution systems with additives through hydrogen-bonding interactions.
Co-reporter:Fei Lu;Lejun Wang;Chao Zhang;Bowen Cheng;Yong Huang
Cellulose 2015 Volume 22( Issue 5) pp:3077-3087
Publication Date(Web):2015 October
DOI:10.1007/s10570-015-0740-x
Rheological properties of cellulose solutions in 1-ethyl-3-methylimidazolium chloride/dimethyl sulfoxide ([Emim]Cl/DMSO, 7/3, w/w) in a wide range of concentration and temperature were investigated. The viscosity of cellulose/[Emim]Cl/DMSO solution agrees well with the complex viscosity suggesting Cox–Merz law is valid for the solution. The viscosity contributed by cellulose (η0–ηs) and cellulose concentration (c) scales as (η0–ηs)~cn with n in the range of 2.00–1.57 and 4.52–3.79 in semidilute unentangled and semidilute entangled regimes, respectively, in the temperature of 25–100 °C. Intrinsic viscosity of the solutions remains constant at temperature below 60 °C and decreases linearly with the increase of temperature above 60 °C. The activation energy of cellulose/[Emim]Cl/DMSO solution increases with the increase in cellulose concentration. The chain dynamics of cellulose in [Emim]Cl/DMSO follows Zimm model and Rouse model in dilute regime (lower than 0.5 wt%) and semidilute unentangled regime (between 0.5 and 2 wt%), respectively.
Co-reporter:Ning Che, Saina Yang, Hongliang Kang, Ruigang Liu, Zhuang Li, Zhijing Liu, Pingping Li, Xiaozhong Qu and Yong Huang
Polymer Chemistry 2014 vol. 5(Issue 24) pp:7109-7120
Publication Date(Web):02 Sep 2014
DOI:10.1039/C4PY00987H
Dextran graft poly((N-amidino)hexyl methacrylamide) (Dex-g-PAHMA) copolymers were synthesized by free radical polymerization in aqueous solution and characterized. Dex-g-PAHMA copolymers can self-assemble into micelles with the PAHMA rich core and dextran rich shell in aqueous media. The CO2 sensitivity of the micelles was investigated by dynamic light scattering (DLS), conductivity and zeta potential. The results confirmed that the Dex-g-PAHMA copolymer micelles have reversible CO2 sensitivity. The micelles can be used as doxorubicin (DOX) carriers and DOX molecules are mainly located in the core of the micelles. The MTT assay indicated that the Dex-g-PAHMA graft copolymers are non-toxic to cells in the copolymer concentration range of 5–1000 μg mL−1, whereas the relative cell viability is greatly reduced with the increase of copolymer concentration for DOX-loaded micelles. The DOX-loaded micelles can be endocytosed by MCF-7 cells and the DOX can release from micelles and diffuse into the cell nucleus. The Dex-g-PAHMA copolymers have promising applications as drug carriers for cancer therapy.
Co-reporter:Zhuang Li, Hongliang Kang, Ning Che, Zhijing Liu, Pingping Li, Weiwei Li, Chao Zhang, Chun Cao, Ruigang Liu, Yong Huang
Carbohydrate Polymers 2014 Volume 111() pp:18-24
Publication Date(Web):13 October 2014
DOI:10.1016/j.carbpol.2014.04.017
•Core-sheath electrospun nanofibers with naproxen and naproxen-loaded liposomes in the core were produced.•Naproxen-loaded hybrid and core-sheath nanofibers were also prepared for comparison.•Naproxen formed hydrogen bonds with the polymer molecules and dispersed homogenously in the polymer matrixes.•Hybrid and core-sheath nanofibers released the naproxen in 24 h.•Liposome-loaded core-sheath nanofibers showed a specific drug release behavior with a burst release within 8 h and then a sustained drug release as long as 12 days.Naproxen (NAP) loaded nanofibers of different structures have been successfully prepared by electrospinning. The structures of the nanofibers are NAP and cellulose acetate (CA) mixed nanofibers (NF-1), nanofibers with NAP/CA mixed core and CA sheath (NF-2), and NAP loaded liposomes and sodium hyaluronate (HA-Na) mixed core with CA sheath (NF-3). The structure and morphology of the nanofibers were characterized and the drug release behaviors were investigated. It was found that NAP can disperse in the HA-Na or CA matrix in molecular level without formation of NAP crystals and dimers. The drug release behaviors of NF-1 and NF-2 show a non-Fickian diffusion mechanism, while the NF-3 shows a specific drug release behavior with a burst release within 8 h followed by a sustained drug release for 12 days. The particular two-stage drug release behavior of NF-3 nanofibers offers the materials promising applications as wound dressing materials.
Co-reporter:Hongliang Kang, Yang Shu, Zhuang Li, Bo Guan, Shunjin Peng, Yong Huang, Ruigang Liu
Carbohydrate Polymers 2014 100() pp: 158-165
Publication Date(Web):
DOI:10.1016/j.carbpol.2013.07.051
Co-reporter:Zhiwei Jiang, Yan Fang, Junfeng Xiang, Yanping Ma, Ang Lu, Hongliang Kang, Yong Huang, Hongxia Guo, Ruigang Liu, and Lina Zhang
The Journal of Physical Chemistry B 2014 Volume 118(Issue 34) pp:10250-10257
Publication Date(Web):August 11, 2014
DOI:10.1021/jp501408e
The dissolution of cellulose in NaOH/urea aqueous solution at low temperature is a key finding in cellulose science and technology. In this paper, 15N and 23Na NMR experiments were carried out to clarify the intermolecular interactions in cellulose/NaOH/urea aqueous solution. It was found that there are direct interactions between OH– anions and amino groups of urea through hydrogen bonds and no direct interaction between urea and cellulose. Moreover, Na+ ions can interact with both cellulose and urea in an aqueous system. These interactions lead to the formation of cellulose–NaOH–urea–H2O inclusion complexes (ICs). 23Na relaxation results confirmed that the formation of urea–OH– clusters can effectively enhance the stability of Na+ ions that attracted to cellulose chains. Low temperature can enhance the hydrogen bonding interaction between OH– ions and urea and improve the binding ability of the NaOH/urea/H2O clusters that attached to cellulose chains. Cryo-TEM observation confirmed the formation of cellulose–NaOH–urea–H2O ICs, which is in extended conformation with mean diameter of about 3.6 nm and mean length of about 300 nm. Possible 3D structure of the ICs was proposed by the M06-2X/6-31+G(d) theoretical calculation, revealing the O3H···O5 intramolecular hydrogen bonds could remain in the ICs. This work clarified the interactions in cellulose/NaOH/urea aqueous solution and the 3D structure of the cellulose chain in dilute cellulose/NaOH/urea aqueous solution.
Co-reporter:Chao Zhang, Ruigang Liu, Junfeng Xiang, Hongliang Kang, Zhijing Liu, and Yong Huang
The Journal of Physical Chemistry B 2014 Volume 118(Issue 31) pp:9507-9514
Publication Date(Web):July 15, 2014
DOI:10.1021/jp506013c
Understanding the interactions between solvent molecules and cellulose at a molecular level is still not fully achieved in cellulose/N,N-dimethylacetamide (DMAc)/LiCl system. In this paper, cellobiose was used as the model compound of cellulose to investigate the interactions in cellulose/DMAc/LiCl solution by using Fourier transform infrared spectroscopy (FTIR), 13C, 35Cl, and 7Li nuclear magnetic resonance (NMR) spectroscopy and conductivity measurements. It was found that when cellulose is dissolved in DMAc/LiCl cosolvent system, the hydroxyl protons of cellulose form strong hydrogen bonds with the Cl–, during which the intermolecular hydrogen bonding networks of cellulose is broken with simultaneous splitting of the Li+–Cl– ion pairs. Simultaneously, the Li+ cations are further solvated by free DMAc molecules, which accompany the hydrogen-bonded Cl– to meet electric balance. Thereafter, the cellulose chains are dispersed in molecular level in the solvent system to form homogeneous solution. This work clarifies the interactions in the cellulose/DMAc/LiCl solution at molecular level and the dissolution mechanism of cellulose in DMAc/LiCl, which is important for understanding the principle for selecting and designing new cellulose solvent systems.
Co-reporter:Zhuang Li, Hongliang Kang, Qinmei Li, Ning Che, Zhijing Liu, Pingping Li, Chao Zhang, Ruigang Liu, Yong Huang
Colloids and Surfaces B: Biointerfaces 2014 Volume 122() pp:630-637
Publication Date(Web):1 October 2014
DOI:10.1016/j.colsurfb.2014.07.042
•Small unilamellar vesicles (SUVs) in the diameter about 50 nm were prepared and stabilized by sodium hyaluranate (HA-Na) aqueous solution.•Liposome-loaded core–sheath HA-Na/PVP ultrathin fibers were produced by coaxial electrospinning.•SUVs dispersed in the core HA-Na matrix and were in the elliptical shape.•SUVs were stable within the core–sheath fibers and can be rehydrated in water.Ultrathin core–sheath fibers with small unilamellar vesicles (SUVs) in the core were prepared by coaxial electrospinning. SUVs/sodium hyaluranate (HA-Na)/water and polyvinylpyrrolidone (PVP)/ethanol solutions were used as core and sheath fluid in electrospinning, respectively. The ultrathin fibers were characterized by scanning and transmission electron microscopy (SEM and TEM) and laser scanning confocal microscopy (LSCM). The SUVs were successfully encapsulated in the core HA-Na matrix of the ultrathin fibers and are in the elliptic shape. The SUVs encapsulated in the core matrix of the ultrathin fibers have an excellent stability. The SUVs embedded in the ultrathin fibers are stable. When the ultrathin fibers were re-dissolved in water after one-month storage at room temperature, the rehydrated SUVs have the similar size and size distribution as the as-prepared SUVs. The liposome-loaded ultrathin fiber mats have the promising applications in wound healing materials.
Co-reporter:Weiwei Li, Ruigang Liu, Hongliang Kang, Yunming Sun, Fengying Dong and Yong Huang
Polymer Chemistry 2013 vol. 4(Issue 8) pp:2556-2563
Publication Date(Web):05 Feb 2013
DOI:10.1039/C3PY00052D
In this paper, amidoxime functionalized cellulose (AOFC) derivatives have been synthesized by a two step approach and characterized. Firstly, cyanoethyl cellulose (CEC) was synthesized by using Michael addition between acrylonitrile and hydroxyl groups of cellulose in the homogeneous cellulose/NaOH/urea solution. The nitrile groups of CEC were then converted into amidoxime groups using NH2OH. The optimal reaction parameters for the amidoximization are at a pH of 7 and a reaction temperature of 75 °C. More than 90% of the nitrile groups of CEC can be converted into amidoxime groups after the reactions were carried out under these conditions for 8 h. The degree of substitution of amidoxime groups per glucose unit of cellulose can be adjusted by varying the feeding molar ratio of the acrylonitrile to the anhydroglucose units in the reaction solution during the synthesis of CEC. The new cellulose derivative AOFC can be used as both a reducing agent and stabilizer for preparing gold nanoparticles (AuNPs). The AOFC stabilized AuNPs have the excellent stability in whole pH range, which may have the promising applications in the fields of catalysis, biotechnology and medicine.
Co-reporter:Xin Jin, Hongliang Kang, Ruigang Liu, Yong Huang
Carbohydrate Polymers 2013 Volume 95(Issue 1) pp:155-160
Publication Date(Web):5 June 2013
DOI:10.1016/j.carbpol.2013.03.011
•Thermal sensitive cellulose graft copolymer is synthesized via SET-LP.•The control of SET-LP graft copolymerization depends on solvent.•LCST of the graft copolymers in aqueous solution is adjusted to body temperature.•Thermal sensitivity is due to the change of hydrophilicity of HPC backbone via the graft of short PNIPAm chain.Hydroxyproyl cellulose graft poly(N-isopropylacryamide) (HPC-g-PNIPAm) copolymers were synthesized by single-electron transfer living radical polymerization (SET-LRP) in water and THF mixture solvent and characterized. The controllability and polymerization rate of SET-LRP can be adjusted by the water/THF ratio in the mixture solvent. The monomer conversion rate is relatively low in the solvent with low water content. The thermal responsive property of HPC-g-PNIPAm copolymers in aqueous solution depends on the length of the graft chains. The relatively short PNIPAm side chains (<150 repeat units) can effectively regulate the low critical solution temperature (LCST) of the HPC-g-PNIPAm copolymers in aqueous solution due to the hydrophilic properties of the short PNIPAm chains. This work provides an approach for the regulation of the LCST to body temperature region by graft copolymerization.
Co-reporter:Yizhong Huang, Hongliang Kang, Guanghua Li, Chunying Wang, Yong Huang and Ruigang Liu
RSC Advances 2013 vol. 3(Issue 36) pp:15909-15916
Publication Date(Web):05 Jul 2013
DOI:10.1039/C3RA43031F
Azobenzene functionalized hydroxypropyl cellulose derivatives (azo-HPCs) with different degrees of substitution with azobenzene moieties were synthesized and characterized. The degree of substitution with the azobenzene moieties (DSazo) can be adjusted by changing the feed ratio in the reaction mixture. The photosensitivity of the azo-HPCs in both solution and solution film was investigated. The azobenzene moieties of the azo-HPCs exhibited a reversible cis-to-trans isomerization transition upon irradiation with UV and visible light in both solution and the solid state. The reversible trans-to-cis photoisomerization led to a change of the wettability of the azo-HPC films. Surface energy estimations suggest that the tunable film wettability was attributed to the change of the dipole moment of the azobenzene moieties in the film surface. The variation of the contact angle depends on the DSazo of the azo-HPC derivatives. A higher DSazo corresponds to a larger variation of water contact angle upon UV irradiation under the same conditions. This work offers a versatile method to manipulate the surface properties of the eco-friendly cellulose derivatives.
Co-reporter:Hongliang Kang;Yong Huang
Polymer International 2013 Volume 62( Issue 3) pp:338-344
Publication Date(Web):
DOI:10.1002/pi.4455
Abstract
In this review, recent progresses in the synthesis of new cellulose derivatives and graft copolymers are summarized. Cellulose derivatives synthesized in new cellulose solvents, such as ionic liquids and NaOH/urea, and the regioselective synthesis of cellulose derivatives have attracted increasing attention in recent years and could be a more active field for cellulose in the future. Cellulose graft copolymers with well-defined architectures synthesized by controlled/living radical polymerizations such as atomic transfer radical polymerization and their stimuli-induced assembly have been investigated extensively. Stimuli-responsive functional materials can be fabricated using either cellulose derivatives or graft copolymers, and they can be used as biosensors and carriers for controlled delivery of drugs and genes. The fabrication of functional materials with cellulosic blocks and their applications have a bright future. © 2013 Society of Chemical Industry
Co-reporter:Qinmei Li, Lijun Zhu, Ruigang Liu, Da Huang, Xin Jin, Ning Che, Zhuang Li, Xiaozhong Qu, Hongliang Kang and Yong Huang
Journal of Materials Chemistry A 2012 vol. 22(Issue 37) pp:19964-19973
Publication Date(Web):13 Aug 2012
DOI:10.1039/C2JM34136K
A novel drug carrier with dual triggerable release properties based on keratin graft poly(ethylene glycol) (keratin-g-PEG) copolymers is reported. Keratin-g-PEG copolymers with different graft densities are synthesized through thiol–ene click chemistry. Taking advantage of the amphiphilicity and the thiol groups of the graft copolymer, nanoparticles stabilized with PEG chains and keratin as the core, bearing glutathione (GSH) cleavable cross-links, are fabricated in aqueous solutions. The keratin-g-PEG copolymer nanoparticles can serve as excellent carriers for doxorubicin hydrochloride salt (DOX·HCl) with a highest loading capacity of 18.1% (w/w). The release of the loaded DOX is sensitive to the concentration of GSH, especially at a GSH concentration of cellular level. Trypsin can further trigger the release of the loaded DOX in the nanoparticles. In vitro cellular uptake experiments indicate that DOX released from the DOX-loaded keratin-g-PEG nanoparticles can be internalized into the cells efficiently, and the loaded DOX shows a faster release into the nuclei of the cells under higher GSH concentrations. The carriers have promising applications as drug carriers for intracellular drug delivery for cancer therapy.
Co-reporter:Qinmei Li;Hongliang Kang
Chinese Journal of Chemistry 2012 Volume 30( Issue 9) pp:2169-2175
Publication Date(Web):
DOI:10.1002/cjoc.201200658
Abstract
Ethyl cellulose graft copolymers with block and hetero side chains, ethyl cellulose graft [polystyrene-b-poly(ethylene glycol)] [EC-g-(PS-b-PEG)] and ethyl cellulose graft polystyrene and polyethylene glycol [EC-g-(PS-PEG )] were synthesized by atomic transfer radical polymerization (ATRP) and alkyne-azide "click" reactions and "one-pot" ATRP and "click" reactions, respectively. For the synthesis of EC-g-(PS-b-PEG), the macroinitiator for ATRP was first synthesized via the esterification of hydroxyl groups of EC with 2-bromoisobutyryl bromide to result ethyl cellulose 2-bromoisobutyryl ester (EC-Br). The degree of substitution of bromide groups, which determined the graft density, can be tailored by varying the feeding ratios of the hydroxyl groups to 2-bromoisobutyryl bromide. Then ATRP was carried out for preparing EC-g-PS-Br with well-defined length of PS chains. The EC-g-PS-Br copolymers were then converted to EC-g-PS-N3 and then reacted with end alkyne-functionalized PEG via click to result in EC-g-(PS-b-PEG). The EC-g-(PS-PEG) copolymers were synthesized by converting bromide groups of EC-Br to azide groups (EC-Br-N3) and then by one-pot ATRP and "click" reactions. The resultant graft copolymers were characterized by FTIR and 1H NMR. The results indicate the success of the synthetic procedure of the cellulose graft copolymers with block and hetero side chains.
Co-reporter:Wenyong Liu, Yuejun Liu, Guangsheng Zeng, Ruigang Liu, Yong Huang
Polymer 2012 Volume 53(Issue 4) pp:1005-1014
Publication Date(Web):17 February 2012
DOI:10.1016/j.polymer.2012.01.006
The chain conformation and individual chain structures of the graft copolymers ethyl cellulose grafting poly (acrylic acid) (EC-g-PAA) were investigated by laser light scattering (LLS) and atom force microscopy (AFM). The EC-g-PAA graft copolymers with two different side chain lengths and side chain grafting densities were synthesized via atom transfer radical polymerization (ATRP) from ethyl cellulose as the backbone. The graft copolymer molecules are adsorbed on the mica surface, and the observed single molecule structures by AFM reflect the molecular conformation in solution. An increase of the graft density of the graft copolymer induces the conformational transition due to the repulsion between side chains from coil to rod conformation. The observed disclike and rodlike single chain structures response to the coil and rod conformations, respectively. The results provide a direct visual experimental evidence of chain conformational and single chain structural transitions for graft copolymers in common solvents induced by graft density.
Co-reporter:Hongliang Kang, Ruigang Liu, Huafeng Sun, Jieming Zhen, Qinmei Li, and Yong Huang
The Journal of Physical Chemistry B 2012 Volume 116(Issue 1) pp:55-62
Publication Date(Web):December 7, 2011
DOI:10.1021/jp2083488
Thermo-, pH-, and electrochemical-sensitive cellulose graft copolymers, hydroxypropyl cellulose-g-poly(4-vinylpyridine)-Os(bipyridine) (HPC-g-P4VP-Os(bpy)), were synthesized and characterized. The electrochemical properties of the resulting material were investigated via cyclic voltammetry by coating the graft copolymers on the platinized carbon electrode. The results indicated that the electrochemical properties of the graft copolymer modified electrode were responsive to the pH values of the electrolyte solution. The reversible transformation between the active and inactive state originated from the changes in the architecture of the HPC-g-P4VP-Os(bpy) graft copolymer at different pH values. At high pH (e.g., above the pKa of P4VP), the chains of P4VP collapsed, and the electrochemical activity of the electrode was reduced. With immobilization of glucose oxidase (GOx) on the graft copolymer decorated electrode, a biosensor for glucose detection was prepared. The current of the biosensor depended on the glucose concentration in the detected solution and increased with the successive addition of glucose.
Co-reporter:Junjun Tan, Hongliang Kang, Ruigang Liu, Deqian Wang, Xin Jin, Qinmei Li and Yong Huang
Polymer Chemistry 2011 vol. 2(Issue 3) pp:672-678
Publication Date(Web):25 Nov 2010
DOI:10.1039/C0PY00348D
A new type of cellulose derivative was synthesized by means of conjugating cysteamine to hydroxypropyl cellulose (HPC) and the degree of thiol groups could be controlled by the feed ratio of the reactants. The thiolated HPC (HPC–SH) maintains the thermosensitivity of HPC and the thiol groups on the HPC chain can be oxidized to disulfide bonds. Cytotoxity tests performed on MG-63 cells proved that HPC–SH is not harmful to the cells. Nanogels can be fabricated by the self-association of HPC–HS in the solution at 45 °C and then oxidation of thiol groups to disulfide bonds occurs to stabilize the associated structure. The crosslinking degree of the nanogels could be controlled by the substitution degree of thiol groups (–SH) in the thiolated HPC. The hydrodynamic radius of the nanogels can be tuned by adjusting the degree of crosslinking and the concentration of the initial thiolated HPC solution in the self-association process. The hydrodynamic radius of the nanogels can be changed with the temperature and the dissociation process can happen by adding the reducing agent dithiothreitol (DTT). The dual-stimuli sensitive nanogels may have potential applications in controlled drug release, transfer switch device and sensors.
Co-reporter:Deqian Wang, Ruigang Liu, Ning Che, Qinmei Li, Zhuang Li, Ye Tian, Honglang Kang, Bing Jia and Yong Huang
Polymer Chemistry 2011 vol. 2(Issue 8) pp:1872-1878
Publication Date(Web):02 Jun 2011
DOI:10.1039/C1PY00168J
Dextran
graft copolymers, including dextran graft poly(N-methacryloylglycylglycine) copolymers conjugated with polyethylene glycol and tyrosine (Dex-g-PMAGGCONHPEG3k-NHTyr), dextran graft poly(N-(2-hydroxypropyl) methacrylamide-co-N-methacryloylglycylglycine)-tyrosine conjugates (Dex-g-P(HPMA-co-MAGGCONHTyr)), and dextran graft poly(methacrylpolyethylene glycol-co-N-methacryloylglycylglycine)-tyrosine conjugates (Dex-g-P(MPEG-co-MAGGCONHTyr)) were synthesized for the purpose to improve the biodistribution and blood clearance time of ploy(N-methacryloylglycylglycine)-tyrosine conjugates (Dex-g-PMAGGCONHTyr). Dynamic light scattering (DLS) results indicated that no aggregation formed in 0.9% saline solution. The graft copolymers were labeled with 125I and the labeled copolymers are stable in 0.9% saline and 1% BSA of PBS solutions. Pharmacokinetics studies showed that 125I labeled graft copolymer Dex-g-P(HPMA-co-MAGGCONHTyr) had a longer blood clearance time than the others. Biodistribution images confirmed the preferable liver and spleen accumulation at 1 h after injection, and especially for blood tissue, the mean %ID/g value of the PHPMA-modified graft copolymer Dex-g-P(HPMA-co-MAGGCONHTyr) is 7 folds higher than that of Dex-g-PMAGGCONHTyr.
Co-reporter:Deqian Wang, Junjun Tan, Hongliang Kang, Lin Ma, Xin Jin, Ruigang Liu, Yong Huang
Carbohydrate Polymers 2011 Volume 84(Issue 1) pp:195-202
Publication Date(Web):11 February 2011
DOI:10.1016/j.carbpol.2010.11.023
The pH-responsive ethyl cellulose graft poly(2-(diethylamino) ethyl methacrylate) (EC-g-PDEAEMA) copolymers were synthesized through atom transfer radical polymerization (ATRP). Kinetic analysis confirmed the reaction is living and controllable. The graft copolymers can form micelles in acid aqueous medium. The critical micelle concentration (CMC) of the graft copolymers decreases with the increase of the graft length and graft density. The resultant micelles show the pH-sensitivity. The decrease in the hydrodynamic radius of the micelles at pH 6–6.9 attributes to collapse of the side PDEAEMA chains in the shell of the micelles due to the deprotonation, which was further confirmed by TEM observation. The loading and controlled release of drugs in the micelles was investigated by using rifampicin (RIF) as the model drug. It was found that the cumulant release of RIF in the buffer solution at pH 6.6 is higher than that at pH 7.4.
Co-reporter:Wen Wang;Hongliang Kang;Weili Liu
Colloid and Polymer Science 2011 Volume 289( Issue 4) pp:371-379
Publication Date(Web):2011 February
DOI:10.1007/s00396-011-2374-3
The photo-polymerization-induced banded texture of ethyl-cyanoethyl cellulose/acrylic acid/copper acrylate ((E-CE)C/AA/CuAA2) cholesteric liquid crystalline (CLC) solutions were investigated. The results indicate that the CLC phase can be fixed by the photo-polymerization. Banded texture was obtained in the photo-polymerized CLC films. The orientation of the banded texture induced by the photo-polymerization depends on the gradient of UV irradiations on the surface of the (E-CE)C/AA/CuAA2 CLC solutions. CLC films with different patterns can be obtained by introducing the UV irradiation gradient on the (E-CE)C/AA/CuAA2 CLC solutions surface by using masks with different patterns. The simple approach for the fabrication of CLC films with different patterns may have the potential application in the fields of holographic image storage.
Co-reporter:Kai Zheng, Ruigang Liu, Hongliang Kang, Xia Gao, Deyan Shen, Yong Huang
Polymer 2011 Volume 52(Issue 16) pp:3671-3676
Publication Date(Web):20 July 2011
DOI:10.1016/j.polymer.2011.06.007
The induced circular dichroism (ICD) syndiotactic polystyrene (sPS) chiral films in sPS δ phase were prepared and the chirality of the ICD sPS films upon annealing at different temperature was investigated. The sPS δ crystals in the ICD films transform into γ and then into α crystals as those of achiral sPS δ crystals during annealing at different temperature. The CD signal intensity at λ of 200 nm remains unchanged during the δ to γ crystalline transformation, but enhanced tremendously during the γ to α crystalline transformation. The amplification CD signal attributes to the closer package of the phenol rings in sPS α phase than that in sPS δ and γ phases. The lamellae grown at a temperature above the γ to α transition follow the chiral aggregation structure, which also contribute to the amplification of the CD signal.
Co-reporter:Deqian Wang, Jiyun Shi, Junjun Tan, Xin Jin, Qinmei Li, Honglang Kang, Ruigang Liu, Bing Jia, and Yong Huang
Biomacromolecules 2011 Volume 12(Issue 5) pp:
Publication Date(Web):April 6, 2011
DOI:10.1021/bm200194s
Dextran graft poly (N-methacryloylglycylglycine) copolymer–tyrosine conjugates (dextran-g-PMAGGCONHTyr) were synthesized and characterized. Dynamic light scattering (DLS) results indicated that the graft copolymers are soluble in pH 7.4 PBS and 0.9% saline solutions. The graft copolymers were labeled with 125I, and the labeling stability in 0.9% saline solution was investigated. Pharmacokinetics studies showed a rapid clearance of 125I-labeled graft copolymers from the blood pool. Biodistribution images confirmed the preferable liver and spleen accumulation within 1 h after injection and rapid clearance from all the organs over time. The graft copolymer with molecular weight of 9.8 kDa was eliminated from the kidney significantly faster than those with higher molecular weight. The effect of the numbers of −COOH groups on the graft copolymers on the biodistribution was also investigated. It was found that the graft copolymers with the average number of −COOH groups per glucopyranose unit (DS–COOH) of 0.57 and 0.18 are mainly distributed in liver and spleen at 1 h after injection, whereas the graft copolymer with DS–COOH of 0.07 is mainly accumulated in kidney.
Co-reporter:Junjun Tan, Yanxiang Li, Ruigang Liu, Hongliang Kang, Deqian Wang, Lin Ma, Wenyong Liu, Min Wu, Yong Huang
Carbohydrate Polymers 2010 Volume 81(Issue 2) pp:213-218
Publication Date(Web):11 June 2010
DOI:10.1016/j.carbpol.2010.02.017
The micellization and sustained drug release behavior of ethyl cellulose graft poly(poly(ethylene glycol) methyl ether methacrylate) (EC-g-PPEGMA) copolymers with well-defined structure were investigated by using pyrene as the fluorescent probe and model drug. It was found that the EC-g-PPEGMA copolymers have a low critical micelle concentration (CMC) at about 5 × 10−4 mg/mL. Drug loading experiments indicate that a low graft density of the copolymers corresponds to a higher drug loading efficiency and a higher loading capacity of drug in the micelles. The release rate of the loaded pyrene depends on both the length of the side chains and the loading capacity of pryene in the micelles. A shorter side chain of the copolymer and a higher ratio of the copolymer to the pyrene in the micelles correspond to a lower release rate. The self-assembly system shows a potential application in controlled drug delivery.
Co-reporter:Kai Zheng, Ruigang Liu and Yong Huang
Polymer Journal 2010 42(1) pp:81-85
Publication Date(Web):2010-01-01
DOI:10.1038/pj.2009.304
The conformational changes of syndiotactic polypropylene (sPP) during melting and isothermal crystallization processes were studied by infrared (IR) and two-dimensional (2D) correlation analysis. The band at 963 cm−1 is assigned to the contribution of the amorphous component, and the band at 978 cm−1 is assigned to a shorter helical conformational length than the bands at 867 and 812 cm−1, which are related to crystalline helical conformation. The difference spectra and 2D correlation spectra analysis of the crystallization process indicated that the changes in these regular bands occur in rapid sequence, which is not easily detected by conventional IR spectroscopy. It was found that the absorption intensity of the band at 963 cm−1 increases earlier than that of the band at 978 cm−1, as well as of the bands at 867 and 812 cm−1. The results suggest that the partial chains among the amorphous component change in conformation first, then the sPP chains adjust their local conformations to form short helical conformations and finally crystallization occurs.
Co-reporter:Junjun Tan, Ruigang Liu, Wen Wang, Wenyong Liu, Ye Tian, Min Wu and Yong Huang
Langmuir 2010 Volume 26(Issue 3) pp:2093-2098
Publication Date(Web):September 1, 2009
DOI:10.1021/la902593e
A pH-sensitive gold nanoparticle-cysteamine/carboxymethyl cellulose (Au-CA/CMC) dispersion system was prepared by a simple approach. Gold nanoparticles (AuNPs) were first synthesized by directly reducing chloroauric acid (HAuCl4) with sodium carboxymethyl cellulose (CMC). Then the AuNPs were decorated by an electrostatic compound of cysteamine hydrochloride (CA) and sodium carboxymethyl cellulose (CMC) through ligand exchange to get the assembly of Au-CA/CMC. The Au-CA/CMC dispersion system exhibits strongly reversible pH-responsive behavior with the aggregation of AuNPs caused by the combined action of the chain conformation change of CMC and electrostatic interactions between CA and CMC at different pH values. Finally, the reversible aggregation mechanism of AuNPs in the Au-CA/CMC dispersion system has been investigated by transmission electron microscopy (TEM) and ultraviolet−visible spectroscopy (UV−vis spectroscopy). This study provides a new method to fabricate a stimuli-responsive system free from complicated organic synthesis without using a toxic reducing agent.
Co-reporter:Lin Ma, Hongliang Kang, Ruigang Liu, and Yong Huang
Langmuir 2010 Volume 26(Issue 23) pp:18519-18525
Publication Date(Web):November 8, 2010
DOI:10.1021/la103854b
Thermo- and pH-sensitive graft copolymers, hydroxypropylcellulose-graft-poly(4-vinyl pyridine) (HPC-g-P4VP), were synthesized via atom transfer radical polymerization (ATRP) and characterized. The thermo- and pH-induced micellization and stimuli-responsive properties of HPC-g-P4VP graft copolymers in aqueous solution were investigated by transmittance, 1H NMR, dynamic light scattering (DLS), and so on. For the pH-induced micellization, the P4VP side chains collapse to form the core of the micelles, and the HPC backbones stay in the shell to stabilize the micelles. In the case of thermoinduced micellization, the HPC backbones collapse to form the core of the micelles that was stabilized by the P4VP side chains in the shell upon heating. What’s more, the cloud point of the HPC-g-P4VP copolymers in the aqueous solution could be finely tuned by changing the length of P4VP side chains or the pH values. In acidic water, the longer the side chains, the higher the cloud point. For those HPC-g-P4VP copolymers with short side chains, for example, HPC0.05-g-P4VP3, the lower pH correlates a higher cloud point. The thermo- or pH-induced micelles also have the pH- or thermosensitivity due to their P4VP or HPC shells.
Co-reporter:Lin Ma, Ruigang Liu, Junjun Tan, Deqian Wang, Xin Jin, Hongliang Kang, Min Wu and Yong Huang
Langmuir 2010 Volume 26(Issue 11) pp:8697-8703
Publication Date(Web):February 3, 2010
DOI:10.1021/la904431z
The self-assembly and pH- and thermo-sensitivities properties of hydroxypropyl cellulose-graft-poly(N,N-dimethyl aminoethyl methacrylate) (HPC-g-PDMAEMA) copolymers in aqueous solutions were investigated by transmittance, dynamic light scattering (DLS), and 1H NMR spectroscopy. Micelles with different structure can be formed by varying either pH value or temperature. At low pH, e.g., 3.0, the HPC backbone of the copolymer collapse to form the core of micelles stabilized with protonated PDMAEMA side chains on the surface of the micelles upon heating. At the medium pH, e.g., 8.1, both HPC backbone and PDMAEMA side chains collapse upon heating to form unstable aggregates. At high pH, e.g., 12.3, PDMAEMA side chains collapse first to form the core of micelles stabilized with HPC chains upon heating. Further heating the copolymer solution at this pH leads to the aggregation of the micelles due to the collapse of the shell HPC chains. The thermal sensitivity of the HPC-g-PDMAEMA copolymers is reversible.
Co-reporter:Wen Wang;Weili Liu;Junjun Tan;Wenyong Liu
Journal of Materials Science 2010 Volume 45( Issue 20) pp:5567-5573
Publication Date(Web):2010 October
DOI:10.1007/s10853-010-4618-x
Porous silica with hierarchical structures was prepared from ethyl-cyanoethyl cellulose/poly(3-(methacryloyloxy)propyl-trimethoxysilane) (E-CE)C/P(MPTOS) composites with fixed cholesteric liquid crystalline (LC) phase. The scanning and transmission electron microscopy (SEM and TEM) and N2 sorption measurements results indicate that the silica prepared from cholesteric LC composites is of hierarchical macro-, meso- and micro-porous structures, and the average pore size of the silica can be tailored by the content of the cholesteric LC phase in the (E-CE)C/P(MPTOS) composites. The resultant silicas have high specific surface area with the highest value of 837 m2/g at the pore volume of 0.83 cm3/g. This approach provides a new choice for the preparation of porous silica materials, especially from the templates that are not compatible with aqueous system.
Co-reporter:Weili Liu, Ruigang Liu, Wen Wang, Weiwei Li, Wenyong Liu, Kai Zheng, Lin Ma, Ye Tian, Zhishan Bo and Yong Huang
The Journal of Physical Chemistry C 2009 Volume 113(Issue 26) pp:11385-11389
Publication Date(Web):June 8, 2009
DOI:10.1021/jp900042h
We used solvent−vapor treatment methods to determine nanoscale phase separation and thus tailor the charge mobility of the poly(3-hexylthiophene)/fullerene (P3HT/C60) blend films. The nanowires obtained by chloroform vapor treatment are rich in C60, whereas the nanowires obtained by 1,2-dichlorobenzene (DCB) vapor treatment are rich in P3HT. The treated blends offer far superior hole transport than the untreated blends, which is attributed to nanoscale phase separation and a three-dimensional network containing C60 or P3HT nanowires. Meanwhile, the electrically bicontinuous nanoscale morphology realized by controlling the crystallinity of P3HT and C60 using different solvent−vapor results in enhanced absorption in visible light without further heat treatment or preparation in both cases. Solar cells fabricating from the films after treatment show several-fold improvements in power conversion efficiency compared to that of devices having films without treatment.
Co-reporter:Kai Zheng, Ruigang Liu, Haibo Chang, Deyan Shen, Yong Huang
Polymer 2009 50(24) pp: 5782-5786
Publication Date(Web):
DOI:10.1016/j.polymer.2009.10.017
Co-reporter:Wenyong Liu, Ruigang Liu, Yanxiang Li, Hongliang Kang, Dawa Shen, Min Wu, Yong Huang
Polymer 2009 50(1) pp: 211-217
Publication Date(Web):
DOI:10.1016/j.polymer.2008.10.060
Co-reporter:Wenyong Liu, Ruigang Liu, Yanxiang Li, Wen Wang, Lin Ma, Min Wu, Yong Huang
Polymer 2009 50(12) pp: 2716-2726
Publication Date(Web):
DOI:10.1016/j.polymer.2009.04.009
Co-reporter:Hui Yu, Ruigang Liu, Dawa Shen, Zhonghua Wu, Yong Huang
Carbohydrate Polymers 2008 Volume 72(Issue 1) pp:122-127
Publication Date(Web):3 April 2008
DOI:10.1016/j.carbpol.2007.07.035
The arrangement of cellulose microfibrils in the cell wall from different tissues of wheat straw was investigated mainly using atomic force microscope (AFM). It was revealed that cellulose microfibrillar crystals arrange randomly in the parenchyma cell walls and are ordered quite well longitudinal to the fiber axis in the epidermal fibers. The microfibrillar crystals are about 20 nm in diameter and 150–200 nm in length. Moreover, the cellulose microfibrillar crystals in the epidermal fibers align periodically along the fiber axis and the periodicity is similar to the length of the fibrillar crystals. This structure was confirmed by small angle X-ray scattering (SAXS).
Co-reporter:Yanxiang Li;Yong Huang
Journal of Applied Polymer Science 2008 Volume 110( Issue 3) pp:1797-1803
Publication Date(Web):
DOI:10.1002/app.28541
Abstract
Cellulose-graft-poly(ethylene glycol) copolymers were synthesized, and the thermal properties of the copolymers were investigated. The cellulose-graft-poly(ethylene glycol) copolymers showed solid–solid phase-transition behavior with a high thermal storage density and good thermal stability in the temperature region of 25–250°C. The phase-transition temperature and enthalpy of the cellulose-graft-poly(ethylene glycol) copolymers could be adjusted through changes in the poly(ethylene glycol) content. The prepared copolymers could be used as thermal energy storage materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Hongliang Kang;Wenyong Liu;Yong Huang
Macromolecular Chemistry and Physics 2008 Volume 209( Issue 4) pp:424-430
Publication Date(Web):
DOI:10.1002/macp.200700363
Co-reporter:Yanxiang Li;Wenyong Liu;Hongliang Kang;Min Wu;Yong Huang
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 20) pp:6907-6915
Publication Date(Web):
DOI:10.1002/pola.23000
Abstract
Ethyl cellulose graft poly(poly(ethylene glycol) methyl ether methacrylate) (EC-g-P(PEGMA)) amphiphilic copolymers were synthesized via atom transfer radical polymerization (ATRP) and characterized by FTIR, 1H NMR, and gel permeation chromatography. Reaction kinetics analysis indicated that the graft copolymerization is living and controllable. The self-assembly and thermosensitive property of the obtained EC-g-P(PEGMA) amphiphilic copolymers in water were investigated by dynamic light scattering, transmission electron microscopy, and transmittance. It was found that the EC-g-P(PEGMA) amphiphilic copolymers can self-assemble into spherical micelles in water. The size of the micelles increases with the increase of the side chain length. The spherical micelles show thermosensitive properties with a lower critical solution temperature around 65 °C, which almost independent on the graft density and the length of the side chains. The obtained EC-g-P(PEGMA) graft copolymers have both the unique properties of poly(ethylene glycol) and cellulose, which may have the potential applications in biomedicine and biotechnology. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 46: 6907–6915, 2008
Co-reporter:Xia Gao, Ruigang Liu, Yong Huang, Oleksiy Starykov and Wilhelm Oppermann
Macromolecules 2008 Volume 41(Issue 7) pp:2554-2560
Publication Date(Web):March 8, 2008
DOI:10.1021/ma701988w
Syndiotactic polystyrene (sPS) δ crystals within atactic polystyrene (aPS) and atactic polystyrene networks (aPSNW) were prepared. The polymorphism behaviors of sPS within aPS and aPSNW were studied by in-situ wide-angle X-ray diffraction (WAXD) and differential scanning calorimeter (DSC). The sPS δ crystals transfer into γ and then α form crystals during the gradually heating process. The transition temperature of the δ to γ form crystals decreases with the increase in the aPS and aPSNW content in all samples. By contrast, the transition temperature of γ-to-α form crystals increases with the rising aPSNW content, whereas it is independent of the content of aPS. Meanwhile, the transition temperatures of δ to γ and γ to α in aPSNW are higher than those in linear aPS blends. When the samples were annealed at a temperature above 150 °C, the sPS δ form is not favorable to transform into the β form in aPSNW. The results indicate that polymorphism behaviors of sPS are disturbed within aPS networks.
Co-reporter:Jiliang Ci, Hongliang Kang, Chenguang Liu, Aihua He, Ruigang Liu
Carbohydrate Polymers (10 February 2017) Volume 157() pp:
Publication Date(Web):10 February 2017
DOI:10.1016/j.carbpol.2016.10.051
•HPC-g-PMPC copolymers with comb structure were synthesized by ATRP.•LCST of HPC-g-PMPC copolymers was regulated by varying the graft density.•Above the LCST, the aggregates with core-shell structure were obtained.•The anti-adsorption of BSA on the aggregates depended on the side chain length.Zwitterionic graft copolymers, hydroxypropyl cellulose graft poly(2-(methacryloyloxy) ethyl phosphorylcholine) (HPC-g-PMPC) with well-defined architecture were synthesized by atom transfer radical polymerization (ATRP). The self-assembly behaviors and thermal sensitivity of HPC-g-PMPC copolymers and their correlations with graft density and side chain length were investigated in details. HPC-g-PMPC copolymers can self-assemble into spherical aggregate structure above the critical aggregation concentration (CAC) at room temperature. Meanwhile, the size of the aggregates mainly depended on the graft density. The obtained aggregates were thermal sensitive and their low critical solution temperature (LCST) was efficiently regulated by varying the graft density. Above the LCST, the aggregates were transferred into aggregates with core-shell structure, in which the HPC rich core was stabilized by the PMPC rich shell. The interaction between the HPC-g-PMPC aggregates and BSA was investigated. The results indicated that the anti-adsorption of BSA on the aggregates surface depended on the length and graft density of the PMPC zwitterionic side chains.
Co-reporter:Qinmei Li, Lijun Zhu, Ruigang Liu, Da Huang, Xin Jin, Ning Che, Zhuang Li, Xiaozhong Qu, Hongliang Kang and Yong Huang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 37) pp:NaN19973-19973
Publication Date(Web):2012/08/13
DOI:10.1039/C2JM34136K
A novel drug carrier with dual triggerable release properties based on keratin graft poly(ethylene glycol) (keratin-g-PEG) copolymers is reported. Keratin-g-PEG copolymers with different graft densities are synthesized through thiol–ene click chemistry. Taking advantage of the amphiphilicity and the thiol groups of the graft copolymer, nanoparticles stabilized with PEG chains and keratin as the core, bearing glutathione (GSH) cleavable cross-links, are fabricated in aqueous solutions. The keratin-g-PEG copolymer nanoparticles can serve as excellent carriers for doxorubicin hydrochloride salt (DOX·HCl) with a highest loading capacity of 18.1% (w/w). The release of the loaded DOX is sensitive to the concentration of GSH, especially at a GSH concentration of cellular level. Trypsin can further trigger the release of the loaded DOX in the nanoparticles. In vitro cellular uptake experiments indicate that DOX released from the DOX-loaded keratin-g-PEG nanoparticles can be internalized into the cells efficiently, and the loaded DOX shows a faster release into the nuclei of the cells under higher GSH concentrations. The carriers have promising applications as drug carriers for intracellular drug delivery for cancer therapy.
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