Co-reporter:Guangbao Wu, Zhi-Guo Zhang, Yongfang Li, Caiyan Gao, Xin Wang, and Guangming Chen
ACS Nano June 27, 2017 Volume 11(Issue 6) pp:5746-5746
Publication Date(Web):May 16, 2017
DOI:10.1021/acsnano.7b01279
Taking advantage of the high electrical conductivity of a single-walled carbon nanotube (SWCNT) and the large Seebeck coefficient of rylene diimide, a convenient strategy is proposed to achieve high-performance n-type thermoelectric (TE) composites containing a SWCNT and amino-substituted perylene diimide (PDINE) or naphthalene diimide (NDINE). The obtained n-type composites display greatly enhanced TE performance with maximum power factors of 112 ± 8 (PDINE/SWCNT) and 135 ± 14 (NDINE/SWCNT) μW m–1 K–2. A short doping time of 0.5 h can ensure high TE performance. The corresponding TE module consisting of five p–n junctions reaches a large output power of 3.3 μW under a 50 °C temperature gradient. In addition, the n-type composites exhibit high air stability and excellent thermal stability. This design strategy benefits the future fabricating of high-performance n-type TE materials and devices.Keywords: amino-substituted rylene diimide; composite; n-type; single-walled carbon nanotube; thermoelectric;
Co-reporter:Dongxing Tan, Jian Zhao, Caiyan Gao, Hanfu Wang, Guangming Chen, and Donglu Shi
ACS Applied Materials & Interfaces July 5, 2017 Volume 9(Issue 26) pp:21820-21820
Publication Date(Web):June 2, 2017
DOI:10.1021/acsami.7b04938
We report reduced graphene oxide (rGO)/single-walled carbon nanotube (SWCNT) hybrid aerogels with enhanced thermoelectric (TE) performance and removal of organic solvents by designing 3D double-interconnected network porous microstructures. A convenient, cost-effective, and scalable preparation procedure is proposed compared with conventional high-temperature pyrolysis and supercritical drying techniques. The obtained hybrid aerogels are systematically characterized by apparent density, scanning electron microscopy, X-ray photoemission spectroscopy, Raman spectroscopy, and porosity. An enhanced TE performance of ZT ≈ ∼8.03 × 10–3 has been achieved due to the 3D double-interconnected network porous microstructure, the energy-filtering effect, and the phonon scattering at the abundant interfaces and joints. In addition, upon a large axial compression deformation, a high degree of retention of the Seebeck coefficient and a simultaneously significant enhancement of the electrical conductivity are observed. Finally, the hybrid aerogels display high capability for the removal of diverse organic solvents and good recyclability. These findings open a new avenue for exploiting aerogels with multifunctions and widening the applications of TE materials by judicious microstructure design.Keywords: aerogel; carbon nanotube; reduced graphene oxide; solvent removal; thermoelectric;
Co-reporter:Xincheng Hu, Guangming Chen, Xin Wang
Composites Science and Technology 2017 Volume 144(Volume 144) pp:
Publication Date(Web):26 May 2017
DOI:10.1016/j.compscitech.2017.03.018
We present an unusual coral-like coating morphology for the poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) composites with dramatically improved thermoelectric performance. First, the PEDOT/CNT composites are prepared via chemical oxidation polymerization procedure in reverse microemulsions, using hexane or xylene as the reaction medium. The composite films exhibit excellent mechanical flexibility against bending and twisting. Then, the cable-like (in hexane) or coral-like (in xylene) morphology for the thick and uniform coating layer is directly proved by field-emission scanning electron microscopic images. Subsequently, their thermoelectric performances are quantitatively measured at room temperature. After that, the ordered arrangement structures of PEDOT macromolecules, the level of doping and the level of oxidation are investigated by X-ray diffraction technique and X-ray photoelectron spectra, respectively. Finally, the molecular mechanism for the enhanced thermoelectric performance is discussed.
Co-reporter:Lirong Liang;Guangming Chen;Cun-Yue Guo
Materials Chemistry Frontiers 2017 vol. 1(Issue 2) pp:380-386
Publication Date(Web):2017/02/16
DOI:10.1039/C6QM00061D
Controlled synthesis of various nanostructures of polypyrrole (PPy) and their thermoelectric performances have been reported. First, the controlled synthesis and morphological characterization of PPy nanostructures are systematically studied by adjusting the experimental parameters. The effects of oxidant type, oxidant concentration, polymerization period as well as reaction medium are examined. Then, the thermoelectric performances of the as-obtained PPy nanostructures are measured in detail. Finally, the level of doping is calculated by X-ray photoelectron spectra. The relation between PPy nanostructures and their thermoelectric performances has been discussed. The present study will benefit the development of novel organic thermoelectric materials by a morphological design strategy, will deepen our understanding towards structure–thermoelectric function relationship, and will be helpful for the future application of organic polymer thermoelectric materials.
Co-reporter:Jian Zhao;Dongxing Tan;Guangming Chen
Journal of Materials Chemistry C 2017 vol. 5(Issue 1) pp:47-53
Publication Date(Web):2016/12/22
DOI:10.1039/C6TC04613D
Although organic thermoelectric materials have witnessed a rapid progress in recent years, polymer nanostructured thermoelectric materials have received little attention. Here, we report the strong dependence of thermoelectric performance on post-treatments (acid treatment with H2SO4 and chemical reduction using Na2SO3) for the poly(3,4-ethylenedioxythiophene) nanostructure.
Co-reporter:Lianying Wu;Caiyan Gao;Zhibo Li;Guangming Chen
Journal of Materials Chemistry C 2017 vol. 5(Issue 21) pp:5207-5213
Publication Date(Web):2017/06/01
DOI:10.1039/C7TC01246B
Polymer/inorganic nanocomposite (NC) hydrogels usually display super mechanical properties, due to their 3D crosslinked network of delaminated inorganic nanoparticles and polymers as well as strong interfacial interactions. Multiple functions including photoluminescence are strongly desired for their applications. In this study, we report layered rare-earth hydroxide (LRH)/polyacrylamide NC hydrogels with highly colour-tunable photoluminescence functions by a cascaded energy transfer effect. These NC hydrogels based on LRHs containing Gd3+, Tb3+ or Eu3+ ions are fabricated via a convenient and green in situ polymerization procedure. Diverse photoluminescent colours are clearly observed, ranging from green, yellow-green, yellow, reddish-orange, yellowish pink, pink to bluish violet. Furthermore, these NC hydrogels exhibit long luminescence lifetimes and high quantum efficiencies. More interestingly, such fascinating photoluminescence features are highly tunable by varying the constituent or concentration of LRHs, and the excitation wavelength. Finally, a cascaded energy transfer pathway is proposed to elucidate the molecular mechanism of the tunable multiple-colour photoluminescence functions, i.e. the LRH host → sensitizer sodium salicylate (SA) → Tb3+, and finally Tb3+ → Eu3+.
Co-reporter:Guangming Chen;Wei Xu;Daoben Zhu
Journal of Materials Chemistry C 2017 vol. 5(Issue 18) pp:4350-4360
Publication Date(Web):2017/05/11
DOI:10.1039/C6TC05488A
Thermoelectric materials can realize the direct energy conversion between heat and electricity, having diverse applications in energy harvesting (especially for waste heat and low-grade heat) and local cooling and sensing. In recent years, organic polymer thermoelectric composites have received extensive attention and have experienced a rapid development because of their low densities, low thermal conductivities, high flexibilities, and the synergistic combination of the advantages of both constituents. This review covers the recent advances in organic polymer thermoelectric composites. Herein, their preparation strategies have been discussed. In addition, the non-conducting polymer-based composites, ternary composites, and the devices have also been discussed. Finally, an outlook on future investigations is provided.
Co-reporter:Caiyan Gao and Guangming Chen
Journal of Materials Chemistry A 2016 vol. 4(Issue 29) pp:11299-11306
Publication Date(Web):28 Jun 2016
DOI:10.1039/C6TA03988J
Although organic polymer/inorganic particle composites with thermoelectric (TE) performance have witnessed rapid progress in recent years, previous studies mainly focused on a few classically conducting polymers. Schiff base polymers have various advantages such as their ease of preparation, versatile derivatives and adjustable complexation. Unfortunately, studies of Schiff base TE composites are very scarce. The only example reported so far is obtained via a two-step procedure, i.e. synthesis of monomer and subsequent polymerization. Here, we report a convenient one-pot preparation and the TE performances of a series of flexible composite films based on single-walled carbon nanotubes (SWCNTs) and a novel poly-Schiff base, which is achieved via a condensation reaction between glyoxal and p-phenylenediamine. Furthermore, the TE performance of the poly-Schiff base composites reported herein can be conveniently adjusted by chelating transition metal ions. The results reveal that both the preparation method and the poly-Schiff base/SWCNT mass ratio have important impacts on the composite TE performance. The electrical conductivities and the Seebeck coefficients for the physically mixed composites exhibit opposite variation tendencies with poly-Schiff base/SWCNT mass ratio, while the power factors increase with increasing mass ratio. At a poly-Schiff base/SWCNT mass ratio of 1:3, the physically mixed composite reaches the highest power factor of 77.7 ± 5.8 μW m−1 K−2. Finally, by chelating transition metal ions with 1,4-diazabuta-1,3-diene unit of poly-Schiff base, the TE performances of poly-Schiff base/transition metal/SWCNT composites are conveniently adjusted.
Co-reporter:Lirong Liang, Caiyan Gao, Guangming Chen and Cun-Yue Guo
Journal of Materials Chemistry A 2016 vol. 4(Issue 3) pp:526-532
Publication Date(Web):14 Dec 2015
DOI:10.1039/C5TC03768A
Recently, due to their unique advantages over inorganic materials, organic polymer thermoelectric (TE) materials have received considerable attention. However, most studies focus on TE performance enhancement. So far, little attention has been paid to large-area preparation, stretchability, super flexibility and mechanical stability, although these are the intrinsic advantages of polymer materials. Here we report for the first time large-area, stretchable, super flexible and mechanically stable TE films of polymer/carbon nanotube composites. Mechanically stretchable films with a diameter of ∼18 cm are achieved by common vacuum filtration, whose thicknesses and sizes can be conveniently adjusted. Despite direct observations of films under various deformations of bending, rolling or twisting, quantitative measurements of minimum bending radii (<0.6 mm) further confirm the super flexibility. More importantly, after mechanical bending or stretching, no obvious deterioration of TE performance is found. Our findings represent a novel direction of polymer TE materials, and will speed up their applications.
Co-reporter:Lirong Liang, Guangming Chen, Cun-Yue Guo
Composites Science and Technology 2016 Volume 129() pp:130-136
Publication Date(Web):6 June 2016
DOI:10.1016/j.compscitech.2016.04.023
Organic conducting polymer thermoelectric (TE) composites have witnessed a rapid progress in the recent several years. Here, we report a new morphology design strategy to enhance the TE performance by a unique layered morphology containing nanosheets of single-walled carbon nanotubes (SWCNTs) sandwiched by polypyrrole (PPy) nanowires. The free-standing PPy/SWCNT composite films were fabricated via convenient physical mixing followed by vacuum filtration, where PPy nanowires were synthesized by chemical oxidative polymerization. A typical layered morphology, composed of parallel SWCNT nanosheets sandwiched by PPy nanowires with a diameter of 55–75 nm, was directly observed by scanning electron microscopic images. The composites reveal greatly enhanced TE performance with the maximum power factor of 21.7 ± 0.8 μW m−1 K−2, which is the largest value among PPy and its composites reported so far. Furthermore, both SWCNT content and surfactant type have obvious effects on the TE performance. The present study opens a new avenue to greatly enhance the TE performance by construction of layered morphology containing inorganic nanosheets sandwiched by polymer nanostructures.
Co-reporter:Caiyan Gao, Guangming Chen
Composites Science and Technology 2016 Volume 124() pp:52-70
Publication Date(Web):1 March 2016
DOI:10.1016/j.compscitech.2016.01.014
Being green energy materials, thermoelectric (TE) materials can realize direct energy conversions between heat and electricity, thus have widely applications in both TE generators for energy harvesting and local cooling. Especially, low-quality waste heat can be conveniently used. In the recent several years, there is rapidly growing interest in organic conducting polymer/carbon particle TE composites, which synergistically combine the advantages of both carbon particles and polymer materials. In this review, the recent progress is systematically summarized in the order of the dimensionality of the carbon particles (2D, 1D and 0D) and the type of polymer matrix. Synergistic effect and polymer ordered structure, morphological tuning, devices and flexible films are highlighted. Finally, prospects and suggestions for future studies are presented.
Co-reporter:Kongli Xu, Caiyan Gao, Guangming Chen, Dong Qiu
Organic Electronics 2016 Volume 31() pp:41-47
Publication Date(Web):April 2016
DOI:10.1016/j.orgel.2016.01.013
•Effect of polymer orientation on thermoelectric performance is studied by infrared dichroism.•Film stretching led to macromolecular preferred orientation in neat PANI and its composites.•The degree of orientation increased with draw ratio, resulting in enhanced thermoelectric performance.•Obvious anisotropic thermoelectric performance was found.•Carbon nanoparticles had a significant hindrance effect on macromolecular orientation.A direct evidence by infrared dichroism is reported for the first time for the effect of molecular orientation on thermoelectric (TE) performance of organic polymer materials. The preferred orientation was induced by mechanical uni-axial stretching of the films of neat polyaniline (PANI) and its nanocomposites with reduced graphene oxide (rGO) or multi-walled carbon nanotube (MWCNT). Five characteristic bands of Fourier transform infrared (FTIR) spectra were chosen, and quantitative investigations were carried out using the dichroic ratios measured by polarized FTIR spectra. The influences of draw ratio and content of inorganic carbon nanoparticles were taken into account. The results show that the TE performance (including anisotropic TE function) can be conveniently tuned by polymer molecular orientation induced by mechanical stretching, which shed light on the understanding of molecular mechanism towards structure-TE performance relationship, and will speed up the applications of organic polymer TE materials.Direct evidence by infrared dichroism is provided to confirm the effect of molecular orientation on polymer thermoelectric performance.
Co-reporter:Xin Li, Lirong Liang, Mingze Yang, Guangming Chen, Cun-Yue Guo
Organic Electronics 2016 Volume 38() pp:200-204
Publication Date(Web):November 2016
DOI:10.1016/j.orgel.2016.08.022
•Preparation and thermoelectric performance of ternary composites of PEDOT/graphene/CNT were reported.•The ternary composites were prepared by in situ polymerization and subsequent physical mixing.•The ternary composites revealed greatly enhanced thermoelectric performance.•Post-treatment by H2SO4 led to an improvement of thermoelectric performance.Polymer based ternary thermoelectric composites have been studied. Here, poly(3,4-ethylenedioxythiophene)/graphene/carbon nanotube (PEDOT/graphene/CNT) ternary composites are prepared by in situ polymerization and subsequent physical mixing. Then, the morphology is directly observed by scanning electron microscopy. Finally, the thermoelectric performances are measured and discussed, where the effect of acid-treatment is investigated and comparison with those of the neat PEDOT and the binary PEDOT/graphene composite is conducted.
Co-reporter:Xincheng Hu, Guangming Chen, Xin Wang and Hanfu Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 42) pp:20896-20902
Publication Date(Web):29 Sep 2015
DOI:10.1039/C5TA07381B
The thermoelectric performance of a conducting polymer is conveniently and effectively tuned by nanostructure evolution. The electrical conductivity, Seebeck coefficient and power factor follow the same sequence of bulk poly(3,4-ethylenedioxythiophene) (PEDOT) < globular nanoparticle < nanorod or ellipsoidal nanoparticle < nanotube < nanofibre. The molecular mechanism is studied by carrier mobility and concentration, the ordered structure of polymer chains, and the levels of doping and oxidation of PEDOT.
Co-reporter:Zhuang Zhang, Guangming Chen, Hanfu Wang and Wentao Zhai
Journal of Materials Chemistry A 2015 vol. 3(Issue 8) pp:1649-1654
Publication Date(Web):16 Jan 2015
DOI:10.1039/C4TC02471K
A new strategy, i.e. interfacial adsorption-soft template polymerization, is developed to enhance polymer thermoelectric property. The obtained nanocomposite 3D interconnected architecture consisting of reduced graphene oxide (rGO) nanolayers sandwiched by polypyrrole (PPy) nanowires is directly confirmed by scanning and transmission electron microscopies. Moreover, the nanocomposites reveal significantly enhanced thermoelectric performance. At rGO:PPy ratio of 50 wt%, the nanocomposite power factor reaches ∼476.1 times that of pure PPy nanowires. Our results suggest that a greatly enhanced thermoelectric property for polymer nanocomposites can be achieved by a complex morphology design.
Co-reporter:Lianying Wu, Ziqiao Hu, Guangming Chen and Zhibo Li
Soft Matter 2015 vol. 11(Issue 46) pp:9038-9044
Publication Date(Web):21 Sep 2015
DOI:10.1039/C5SM02232K
A convenient green preparation method has been developed to achieve layered double hydroxide (LDH)/polymer nanocomposite (NC) hydrogels. In contrast to previous publications using toxic organic solvent of formamide or methanol in LDH exfoliation or anion exchange, the interlayer anion exchange and exfoliation of LDH are completed in one step with the help of an amino acid (L-serine). The LDH/polyacrylamide (PAM) NC hydrogels are achieved by a convenient exfoliation–adsorption in situ polymerization method. The exfoliation of LDH is characterized by dynamic light scattering and transmission electron microscopy. Interestingly, the developed NC hydrogels reveal ultrahigh deformability and extraordinary stretchability, confirmed by qualitative images and qualitative tensile and compression tests. The molecular mechanism for the ultrahigh deformability and extraordinary stretchability is discussed by crosslinking density, inter-crosslinking molecular weight and swelling tests. We believe that the findings reported herein will deepen our understanding towards the chemistry of network soft materials including gels, and further widen the applications of polymer hydrogels in mechanical devices such as artificial muscles, biomedical devices and drug delivery systems.
Co-reporter:Kongli Xu;Dr. Guangming Chen;Dr. Dong Qiu
Chemistry – An Asian Journal 2015 Volume 10( Issue 5) pp:1225-1231
Publication Date(Web):
DOI:10.1002/asia.201500066
Abstract
Three different in situ chemical oxidative polymerization routes, that is, (A) spin-coating and subsequent liquid layer polymerization, (B) spin-coating followed by vapor phase polymerization, and (C) in situ polymerization and then post-treatment by immersion in ethylene glycol (EG), have been developed to achieve poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (PEDOT/rGO) nanocomposites. As demonstrated by scanning electron microscopic and energy-dispersive X-ray spectroscopic techniques, PEDOT has been successfully coated on the surface of the rGO nanosheets by each of the three preparation routes. Importantly, all of the nanocomposites display a greatly enhanced thermoelectric performance (power factors) relative to those of the corresponding neat PEDOT.
Co-reporter:Zhuang Zhang; Guangming Chen; Hanfu Wang; Xin Li
Chemistry – An Asian Journal 2015 Volume 10( Issue 1) pp:149-153
Publication Date(Web):
DOI:10.1002/asia.201403100
Abstract
A template-directed in situ polymerization preparation of nanocomposites of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-coated multi-walled carbon nanotubes (MWCNTs) with greatly enhanced thermoelectric property is presented. The results reveal that monomeric 3,4-ethylenedioxythiophene was successfully polymerized, enwrapping the surfaces of dispersed MWCNTs (templates) with the aid of PSS. The coated morphology was directly observed by high-resolution transmission electron microscopy. The coated layer was further characterized by energy-dispersive X-ray spectroscopy and X-ray diffraction. In addition, the interfacial interaction between PEDOT:PSS and MWCNTs was studied by Fourier transform infrared spectroscopy. Finally, the thermoelectric measurements show that the obtained PEDOT:PSS/MWCNT nanocomposites exhibited greatly enhanced electrical conductivities, Seebeck coefficients, and power factors when compared with those of neat PEDOT:PSS.
Co-reporter:Ziqiao Hu ;Guangming Chen
Advanced Materials 2014 Volume 26( Issue 34) pp:5950-5956
Publication Date(Web):
DOI:10.1002/adma.201400179
Co-reporter:Ziqiao Hu and Guangming Chen
Journal of Materials Chemistry A 2014 vol. 2(Issue 33) pp:13593-13601
Publication Date(Web):16 Jun 2014
DOI:10.1039/C4TA01590H
Water was used to replace the toxic organic solvent of formamide in preparation of the aqueous dispersions of layered double hydroxide/polyacrylamide (LDH/PAM) nanocomposites, which exhibited greatly enhanced rheological properties when compared to those of the neat PAM. First, the nanocomposite dispersions were prepared via a convenient in situ polymerization or solution mixing method, using water to exfoliate the LDH particles instead of formamide as used in the pioneer investigation. The LDH dispersion structure in the nanocomposite dispersion was demonstrated by X-ray diffraction and direct observation. Then, the rheological investigations including sol → gel transition, dynamic oscillatory frequency sweep and steady shear measurements were carried out. Subsequently, the rheological properties for the aqueous nanocomposite dispersions prepared by the two methods were compared. Finally, the mechanism of the enhancement of rheological properties (the moduli and viscosities) was discussed based on the LDH dispersion microstructure, network formation as well as interfacial interactions between PAM chains and LDH nanoparticles.
Co-reporter:Shaobo Han, Yang Feng, Guangming Chen and Jianjun Wang
RSC Advances 2014 vol. 4(Issue 60) pp:31874-31878
Publication Date(Web):16 Jul 2014
DOI:10.1039/C4RA04468A
A facile method is reported to prepare new polymer composites by introducing functional polymer (poly(3,4-ethylenedioxythiophene)) into a melt-processed film of a thermoplastic polymer matrix with a high melting-temperature (syndiotactic polystyrene), which benefits the applications of functional polymers which are difficult to process and vulnerable to high temperatures.
Co-reporter:Zhuang Zhang and Guangming Chen
RSC Advances 2014 vol. 4(Issue 59) pp:31333-31336
Publication Date(Web):08 Jul 2014
DOI:10.1039/C4RA04273E
The M(II)/M(III) ratio is an important structural feature of layered double hydroxides (LDHs). Here, we report a convenient chemical titration method to measure the M(II)/M(III) ratio of LDHs. The measured results have a relative standard deviation of less than 1.0%, and agree with the data measured by inductively coupled plasma (ICP) atomic emission spectroscopy very well.
Co-reporter:Kongli Xu, Zhuang Zhang, Guangming Chen and Jianquan Shen
RSC Advances 2014 vol. 4(Issue 37) pp:19218-19220
Publication Date(Web):15 Apr 2014
DOI:10.1039/C4RA01987C
We present an unexpected photoluminescence (PL) phenomenon for colloids of pristine MgAl layered double hydroxides (LDHs). Moreover, the PL spectra displayed little dependency on LDH platelet size, excitation wavelength or colloid concentration. The possible mechanism was discussed mainly in terms of specific surface areas, numerous surface defects and excited electron–hole recombination.
Co-reporter:Kongli Xu, Guangming Chen and Jianquan Shen
RSC Advances 2014 vol. 4(Issue 17) pp:8686-8691
Publication Date(Web):20 Jan 2014
DOI:10.1039/C3RA45602A
We present a facile synthesis of layered double hydroxides (LDHs) with submicrometer-sized platelets in lateral dimension, and their subsequent direct decarbonation. First, LDH–carbonate phase (LDH_CO3) with submicrometer-sizes in lateral dimension were controlled synthesized by a facile accelerated urea hydrolysis method. Then, using HNO3–NaNO3 mixed solution, the obtained LDHs with carbonate anions in the interlayer were directly decarbonated to their nitrate form (LDH_NO3). These results are important for the synthesis of novel nanomaterials with controlled morphology and will benefit their applications.
Co-reporter:Zhuang Zhang, Guangming Chen and Jingang Liu
RSC Advances 2014 vol. 4(Issue 16) pp:7991-7997
Publication Date(Web):14 Jan 2014
DOI:10.1039/C3RA46930A
We report a highly tunable photoluminescence of rare-earth (europium, Eu3+) doped layered double hydroxides (LDHs) intercalated by an organic photofunctional anion, courmarin-3-carboxylate (C3C). Novel Eu3+-doped LDHs intercalated by C3C (ZnAlEu–LDH–C3C) with high purity and crystallinity have been successfully synthesized via an interlayer ion exchange process using Eu3+ doped LDH (ZnAlEu–LDH–NO3) as a precursor. A bilayer arrangement with nearly perpendicular orientation was deduced for the C3C anions in the LDH interlayer space. Compared with the precursor, ZnAlEu–LDH–C3C shows a strong UV absorbance and an interesting photoluminescence function, possibly due to an interfacial energy transfer process between the interlayer C3C anions and the Eu3+ within the LDH lattices. The photoluminescent spectra denote a lower symmetry of the coordinating environment around Eu3+ within ZnAlEu–LDH–C3C. More importantly, the photoluminescence of ZnAlEu–LDH–C3C could be highly tuned by simply adjusting the structural constituents (including the content of Eu3+ or C3C) or the excited wavelength. These findings open new avenues to prepare tunable photoluminescent materials and further have potential applications for optical devices.
Co-reporter:Tianchi Cao, Yang Feng, Guangming Chen, Cun-Yue Guo
Reactive and Functional Polymers 2014 Volume 83() pp:1-6
Publication Date(Web):October 2014
DOI:10.1016/j.reactfunctpolym.2014.07.013
Very recently, we report a facile preparation and strong UV-shielding function of poly(ethylene terephthalate) (PET) nanocomposites using 4,4′-diaminostilbene-2,2′-disulfonic acid anion-intercalated layered double hydroxide (LDH_DDA). Herein, the effect of the photofunctional organo anion-intercalated LDH nanoparticles on nonisothermal crystallization kinetics of PET is reported by differential scanning calorimetry technique. First, the nonisothermal crystallization behaviour is discussed by several basic parameters including crystallization peak temperature, relative degree of crystallinity with temperature or time, and half-time of crystallization. Then, Avrami and Jeziorny method, as well as Mo model were applied for the PET/LDH_DDA nanocomposites. Finally, the crystallization activation energy was investigated by Kissinger method and Flynn conversion. The results reveal that the incorporation of LDH_DDA nanoparticles acted as nucleating agent and significantly accelerated the PET nonisothermal crystallization process, whereas had little effect on the three-dimensional growth pattern of spherulites.
Co-reporter:Kongli Xu, Guangming Chen and Dong Qiu
Journal of Materials Chemistry A 2013 vol. 1(Issue 40) pp:12395-12399
Publication Date(Web):23 Aug 2013
DOI:10.1039/C3TA12691A
A novel strategy via the convenient construction of a pie-like structure has been developed to prepare a poly(3,4-ethylenedioxythiophene)–reduced graphene oxide (PEDOT–rGO) nanocomposite with a greatly enhanced thermoelectric performance. Via a template-directed in situ polymerization, thick and uniform coatings of PEDOT layers were conveniently grown on both sides of the rGO nanosheet surfaces due to a strong π–π interfacial interaction. The nanocomposite exhibited a significantly enhanced thermoelectric performance at room temperature with a power factor of 5.2 ± 0.9 × 10−6 W m−1 K−2, greater than 13.3 times that of the PEDOT.
Co-reporter:Zhuang Zhang, Guangming Chen, and Kongli Xu
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 32) pp:11045
Publication Date(Web):July 18, 2013
DOI:10.1021/ie4012326
Colloids of pristine ZnAl layered double hydroxides (LDHs) were found to display an unexpected photoluminescence (PL) phenomenon disparate from the corresponding LDH solids. First, ZnAl LDHs with nitrate in the interlayer were prepared by a hexamethylenetetramine hydrolysis method. Their colloids were obtained by subsequent delamination in formamide at room temperature. Interestingly, an unexpected PL phenomenon was observed for the colloids, different from that of the relevant solid powder. The Zn/Al ratio and concentration did not change the Stokes shift. However, they were found to be the major factors in the emission intensity. Numerous surface defect sites and interaction of LDH with formamide were believed to be the main reasons.
Co-reporter:Yang Feng, Guangming Chen and Jianjun Wang
RSC Advances 2013 vol. 3(Issue 31) pp:12631-12634
Publication Date(Web):20 Jun 2013
DOI:10.1039/C3RA41484A
A convenient quantitative study of a mesophase of syndiotactic polystyrene induced by isothermal annealing was carried out via FT-IR spectroscopy. The absorptivity ratio of mesophase to amorphous phase was found to be independent of annealing time, and varied with annealing temperature. The fraction of mesophase firstly increased with annealing time, then tended to reach a plateau.
Co-reporter:Ziqiao Hu and Guangming Chen
RSC Advances 2013 vol. 3(Issue 30) pp:12021-12025
Publication Date(Web):03 Jun 2013
DOI:10.1039/C3RA42425A
The microstructure evolution, revealed by the rheological behaviour, of green hydrogels containing nanosheets of isethionate-intercalated layered double hydroxides, is presented. In addition, excellent stability towards heating, flowing shear forces and acids/alkalis is reported.
Co-reporter:Cuiping Yuan, Guangming Chen, and Jiping Yang
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 36) pp:11695-11699
Publication Date(Web):August 15, 2012
DOI:10.1021/ie301147h
The orientation structures of both carbon nanotubes (CNTs) and polymer molecular chains in the skin–core structure of polystyrene/multiwalled carbon nanotube (PS/MWCNT) nanocomposite melt-injection-molded pellets were examined. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images clearly show the MWCNT preferred orientation along the melt shearing direction, while polarized Raman spectroscopy results consolidate the MWCNT preferred orientation in each of the skin, medium, and core layers of the injection-molded pellets. By infrared dichroism measurements, a preferred orientation of the PS side groups (phenyl rings) perpendicular to the melt shearing direction was deduced at all depths of the present injection-molded nanocomposite pellet. Meanwhile, the MWCNTs have little effect on the random orientation of the PS main chain (−CH2– groups) with a dichroic ratio near unity.
Co-reporter:Chengqun Jiang, Guangming Chen, Xin Wang
Synthetic Metals 2012 Volume 162(21–22) pp:1968-1971
Publication Date(Web):December 2012
DOI:10.1016/j.synthmet.2012.09.008
High-conversion synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) by chemical oxidative polymerization was studied. Hydrolysis of oxidative agent, and effects of polymerization temperature and time were taken into account. Unlike iron chloride, the oxidative agent of iron sulfate can be effectively used at high temperature, due to the absence of obvious hydrolysis. In addition, high polymerization temperature and long reaction time led to dramatically increase of conversion. Moreover, the structure, morphology and electrical conductivity of the prepared PEDOT with high-conversion had not been changed obviously, when compared with the common low-conversed product obtained at low temperature with short reaction time.Graphical abstractHighlights► High-conversion synthesis of PEDOT by chemical oxidative polymerization is presented. ► Increase of reaction temperature or time led to obvious increase of conversion. ► Structure and morphology of PEDOT with high conversion were well reserved. ► Electrical conductivity of PEDOT with high conversion was not changed.
Co-reporter:Kong Li Xu, Guang Ming Chen, Jian Quan Shen
Chinese Chemical Letters 2012 23(7) pp: 805-808
Publication Date(Web):
DOI:10.1016/j.cclet.2012.05.021
Co-reporter:Cuiping Yuan, Jinhao Zhang, Guangming Chen and Jiping Yang
Chemical Communications 2011 vol. 47(Issue 3) pp:899-901
Publication Date(Web):15 Nov 2010
DOI:10.1039/C0CC03198D
The effect of carbon nanotubes on polymer macromolecular orientation structure during stretching of syndiotactic polystyrene/carbon nanotube nanocomposite film was quantitatively studied for the first time by an infrared dichroism technique.
Co-reporter:Pingjun Fu, Kongli Xu, Hongzan Song, Guangming Chen, Jiping Yang and Yanhua Niu
Journal of Materials Chemistry A 2010 vol. 20(Issue 19) pp:3869-3876
Publication Date(Web):15 Mar 2010
DOI:10.1039/B927391C
Novel polyacrylamide (PAM)/pristine layered double hydroxide (LDH) nanocomposites have been prepared by a facile solution dispersion procedure, and their stability and rheological properties have been studied. The pristine LDHs without any surface organo-modification (LDH_NO3), synthesized by co-precipitation procedure, are dramatically exfoliated and uniformly dispersed in formamide. Subsequently, PAM/LDH_NO3 nanocomposites are prepared by a convenient solution dispersion procedure, wherein the dispersion structure of LDH_NO3 in PAM was studied by X-ray diffraction, size distribution measurements and Tyndall effect. The nanocomposites exhibit excellent stabilities toward various environmental conditions such as heating, centrifugation and salt-tolerance. Moreover, in the whole process of drying and after the re-dissolution, the nanocomposites kept a uniform dispersion structure without any precipitation formation. Finally, the dynamic and steady rheological investigations were conducted. Nanoscale LDH_NO3 particles and layers were found to have drastic effects on the PAM solution rheological behaviour with an obvious gel-formation process at a low LDH content, and strong frequency dependence of viscosity at low frequencies.
Co-reporter:Guoxing Sun, Guangming Chen, Zhengping Liu, Ming Chen
Carbon 2010 Volume 48(Issue 5) pp:1434-1440
Publication Date(Web):April 2010
DOI:10.1016/j.carbon.2009.12.037
A homogeneous dispersion of multi-walled carbon nanotubes (MWCNTs) in syndiotactic polystyrene (sPS) is obtained by a simple solution dispersion procedure. MWCNTs were dispersed in N-methyl-2-pyrrolidinone (NMP), and sPS/MWCNT composites are prepared by mixing sPS/NMP solution with MWCNT/NMP dispersion. The composite structure is characterized by scanning electron microscopy and transmission electron microscopy. The effect of MWCNTs on sPS crystallization and the composite properties are studied. The presence of MWCNTs increases the sPS crystallization temperature, broadens the crystallite size distribution and favors the formation of the thermodynamically stable β phase, whereas it has little effect on the sPS γ to α phase transition during heating. By adding only 1.0 wt.% pristine MWCNTs, the increase in the onset degradation temperature of the composite can reach 20 °C. The electrical conductivity is increased from 10−10∼−16 (neat sPS) to 0.135 S m−1 (sPS/MWCNT composite with 3.0 wt.% MWCNT content). Our findings provide a simple and effective method for carbon nanotube dispersion in polymer matrix with dramatically increased electrical conductivity and thermal stability.
Co-reporter:Jun Liu;Guangming Chen;Jiping Yang;Liping Ding
Journal of Applied Polymer Science 2010 Volume 116( Issue 4) pp:2058-2064
Publication Date(Web):
DOI:10.1002/app.31708
Abstract
Effects of nanoscale dispersed layered double hydroxides (LDHs) on thermal stability of poly(vinyl chloride) (PVC) in thermal and thermooxidative degradation processes are investigated by dynamic and isothermal thermogravimetric analysis (TGA), discoloration test, fourier transform infrared (FTIR), and ultraviolet-visible (UV-vis) spectroscopic techniques. During both stages of thermal degradation, the degradation temperatures, including onset degradation temperature and temperature of the maximum degradation rate, increase, and the final residue yield of the PVC/LDH nanocomposites reaches 14.7 wt %, more than double that for neat PVC. The thermooxidative degradation process is more complex. During the first two stages, the presence of nanoscale dispersed LDH particles enhances the thermal stability, whereas in the last stage accelerates the thermal degradation possibly due to the accumulation of heat released. Additionally, the studies of the isothermal thermooxidative degradation process by FTIR and UV-vis spectra indicate that both polyene backbone formation and some carbonyl groups are simultaneously developed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Jun Liu, Guangming Chen, Jiping Yang, Liping Ding
Materials Chemistry and Physics 2009 Volume 118(2–3) pp:405-409
Publication Date(Web):15 December 2009
DOI:10.1016/j.matchemphys.2009.08.002
A novel interlamellar surface modification of layered double hydroxides (LDHs) via covalent bonding by toluene-2,4-di-isocyanate (TDI) has been successfully obtained, and poly(vinyl chloride) (PVC)/TDI-modified LDH nanocomposites have been prepared via solution intercalation process. After the interlamellar modification, TDI was grafted to the surface hydroxyl groups of LDHs with nitrate, dodecyl sulfate or stearate anion as counterion anion. The structures of the TDI-modified LDHs and the nanocomposites were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and transmission electron microscopy (TEM) techniques. The enhanced thermal stability of PVC/TDI-modified LDH nanocomposites was confirmed by means of conventional Congo Red test and dynamic thermogravimetric analysis (TGA). In addition, the thermal degradation mechanism was briefly discussed on the basis of the above experimental results.
Co-reporter:Pingjun Fu, Guangming Chen, Jun Liu, Jiping Yang
Materials Letters 2009 Volume 63(Issue 20) pp:1725-1728
Publication Date(Web):15 August 2009
DOI:10.1016/j.matlet.2009.05.023
A new intercalated hybrid of polyacrylamide (PAM)/layered double hydroxide (LDH) prepared via in situ intercalative polymerization procedure is reported. LDH with counterion ion of nitrate or dodecyl sulfate anion was employed for comparison. The obtained PAM/LDH hybrid was characterized by X-ray diffraction, infrared spectra, differential scanning microcalorimetry and X-ray photoelectron spectrum. The results reveal that the LDH modified with dodecyl sulfate anion can be used to obtain an intercalated hybrid, whereas PAM polymer chains can not enter the interlayer space of LDH with nitrate anion as counterion ion.
Co-reporter:Guangyang Xu;Guangming Chen;Yongmei Ma;Yucai Ke;Minfang Han
Journal of Applied Polymer Science 2008 Volume 108( Issue 3) pp:1501-1505
Publication Date(Web):
DOI:10.1002/app.27750
Abstract
The rheological properties of a polyamide 6/clay nanocomposite with a low loading of clay (1 wt %) were studied. Linear viscoelastic measurements in oscillatory and steady shear with small strain amplitudes were carried out. The nanocomposite exhibited a higher elastic modulus, viscous modulus, and complex viscosity than neat polyamide 6 during dynamic and steady shear tests. Moreover, the addition of clay resulted in a reduction of the critical strain amplitude, an increase of the loss angle, and a reduction of the frequency at the intersection of the elastic and viscous moduli. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Co-reporter:Guangming Chen
Journal of Applied Polymer Science 2007 Volume 106(Issue 2) pp:817-820
Publication Date(Web):29 JUN 2007
DOI:10.1002/app.26514
A novel poly(vinyl chloride) nanocomposite with layered double hydroxide was successfully prepared via a melt-compounding process in which the positively charged platelets were dramatically exfoliated and homogeneously dispersed. Because of the absorption of the released hydrochloric vapor by both layered double hydroxide platelets and an organomodifier (stearate anions), the added amount of the conventional toxic heavy-metal heat stabilizer could be reduced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Co-reporter:Guangming Chen;Yongmei Ma;Xianjun Zheng;Guangyang Xu;Jun Liu;Jiaqi Fan;Deyan Shen;Zongneng Qi
Journal of Polymer Science Part B: Polymer Physics 2007 Volume 45(Issue 6) pp:654-660
Publication Date(Web):1 FEB 2007
DOI:10.1002/polb.21075
An intercalated polyurethane (PU) /clay nanocomposite was prepared by in situ intercalative polymerization. The PU/clay nanocomposite pellet or film samples were stretched-recovery-restretched, using selfmade microstretching tools. The changes of the basal spacings of clay and the orientation of polymer chain segments during the stretched-recovery-restretched process were studied by wide angle X-ray diffraction (WAXD) and Fourier transform infrared (FTIR) dichoism techniques. The WAXD results show that the basal spacing of clay did not change obviously, indicating that no macromolecular chains entered or moved out of the interlayer space, and the orientations of both hard and soft segments inside the interlayer space did not change obviously, either. The FTIR dichroism tests suggest that outside the interlayer space, the orientation of the hard chain segment increased, decreased, and then increased again during the stretched-recovery-restretched process. However, no obvious changes of the degree of orientation of the soft segment were observed during the processes, the slightly orientation might be released during the relaxation process before the measurements. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 654–660, 2007
Co-reporter:Kongli Xu, Guangming Chen, Jianquan Shen
Applied Clay Science (May 2013) Volumes 75–76() pp:114-119
Publication Date(Web):May 2013
DOI:10.1016/j.clay.2013.02.004
Co-reporter:Zhuang Zhang, Guangming Chen, Kongli Xu
Applied Clay Science (February 2013) Volume 72() pp:206-210
Publication Date(Web):February 2013
DOI:10.1016/j.clay.2013.01.007
Co-reporter:Lianying Wu, Caiyan Gao, Zhibo Li and Guangming Chen
Journal of Materials Chemistry A 2017 - vol. 5(Issue 21) pp:NaN5213-5213
Publication Date(Web):2017/05/04
DOI:10.1039/C7TC01246B
Polymer/inorganic nanocomposite (NC) hydrogels usually display super mechanical properties, due to their 3D crosslinked network of delaminated inorganic nanoparticles and polymers as well as strong interfacial interactions. Multiple functions including photoluminescence are strongly desired for their applications. In this study, we report layered rare-earth hydroxide (LRH)/polyacrylamide NC hydrogels with highly colour-tunable photoluminescence functions by a cascaded energy transfer effect. These NC hydrogels based on LRHs containing Gd3+, Tb3+ or Eu3+ ions are fabricated via a convenient and green in situ polymerization procedure. Diverse photoluminescent colours are clearly observed, ranging from green, yellow-green, yellow, reddish-orange, yellowish pink, pink to bluish violet. Furthermore, these NC hydrogels exhibit long luminescence lifetimes and high quantum efficiencies. More interestingly, such fascinating photoluminescence features are highly tunable by varying the constituent or concentration of LRHs, and the excitation wavelength. Finally, a cascaded energy transfer pathway is proposed to elucidate the molecular mechanism of the tunable multiple-colour photoluminescence functions, i.e. the LRH host → sensitizer sodium salicylate (SA) → Tb3+, and finally Tb3+ → Eu3+.
Co-reporter:Guangbao Wu, Caiyan Gao, Guangming Chen, Xin Wang and Hanfu Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 37) pp:NaN14193-14193
Publication Date(Web):2016/08/19
DOI:10.1039/C6TA05120K
Organic thermoelectric materials are emerging green energy materials, where n-type candidates are of special interest due to the strong demand for thermoelectric modules with flexibility, light weight, large-area fabrication and ease of processing into versatile shapes. Here, an exciting novel strategy to prepare an n-type single-walled carbon nanotube (SWCNT) is proposed by diethylenetriamine (DETA) doping (electron donation) and subsequent CaH2 treatment of the pristine SWCNT (p-type). The Seebeck coefficient and the electrical conductivity for the obtained DETA-CaH2-SWCNT are −41.0 ± 1.5 μV K−1 and 165 ± 10 S cm−1, respectively. A possible mechanism is discussed for the p- to n-type conversion. Then, a multilayered alternating stacked structure is employed to construct thermoelectric modules which realize the conduction layers electrically in series and thermally in parallel. Importantly, the module containing 14 couples displays large open circuit voltages of 62 mV and 125 mV at temperature gradients (ΔT) of 55 K and 110 K, respectively, and a maximum output power of 649 nW at ΔT = 55 K. The strategy proposed here opens a new way to fabricate organic n-type materials and flexible thermoelectric modules. These promising results show great potential in fabrication and applications of flexible and wearable power-conversion devices for next-generation power generators and waste-heat-recovery systems.
Co-reporter:Lirong Liang, Guangming Chen and Cun-Yue Guo
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 2) pp:NaN386-386
Publication Date(Web):2016/08/15
DOI:10.1039/C6QM00061D
Controlled synthesis of various nanostructures of polypyrrole (PPy) and their thermoelectric performances have been reported. First, the controlled synthesis and morphological characterization of PPy nanostructures are systematically studied by adjusting the experimental parameters. The effects of oxidant type, oxidant concentration, polymerization period as well as reaction medium are examined. Then, the thermoelectric performances of the as-obtained PPy nanostructures are measured in detail. Finally, the level of doping is calculated by X-ray photoelectron spectra. The relation between PPy nanostructures and their thermoelectric performances has been discussed. The present study will benefit the development of novel organic thermoelectric materials by a morphological design strategy, will deepen our understanding towards structure–thermoelectric function relationship, and will be helpful for the future application of organic polymer thermoelectric materials.
Co-reporter:Jian Zhao, Dongxing Tan and Guangming Chen
Journal of Materials Chemistry A 2017 - vol. 5(Issue 1) pp:NaN53-53
Publication Date(Web):2016/11/29
DOI:10.1039/C6TC04613D
Although organic thermoelectric materials have witnessed a rapid progress in recent years, polymer nanostructured thermoelectric materials have received little attention. Here, we report the strong dependence of thermoelectric performance on post-treatments (acid treatment with H2SO4 and chemical reduction using Na2SO3) for the poly(3,4-ethylenedioxythiophene) nanostructure.
Co-reporter:Guangming Chen, Wei Xu and Daoben Zhu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 18) pp:NaN4360-4360
Publication Date(Web):2017/04/03
DOI:10.1039/C6TC05488A
Thermoelectric materials can realize the direct energy conversion between heat and electricity, having diverse applications in energy harvesting (especially for waste heat and low-grade heat) and local cooling and sensing. In recent years, organic polymer thermoelectric composites have received extensive attention and have experienced a rapid development because of their low densities, low thermal conductivities, high flexibilities, and the synergistic combination of the advantages of both constituents. This review covers the recent advances in organic polymer thermoelectric composites. Herein, their preparation strategies have been discussed. In addition, the non-conducting polymer-based composites, ternary composites, and the devices have also been discussed. Finally, an outlook on future investigations is provided.
Co-reporter:Pingjun Fu, Kongli Xu, Hongzan Song, Guangming Chen, Jiping Yang and Yanhua Niu
Journal of Materials Chemistry A 2010 - vol. 20(Issue 19) pp:NaN3876-3876
Publication Date(Web):2010/03/15
DOI:10.1039/B927391C
Novel polyacrylamide (PAM)/pristine layered double hydroxide (LDH) nanocomposites have been prepared by a facile solution dispersion procedure, and their stability and rheological properties have been studied. The pristine LDHs without any surface organo-modification (LDH_NO3), synthesized by co-precipitation procedure, are dramatically exfoliated and uniformly dispersed in formamide. Subsequently, PAM/LDH_NO3 nanocomposites are prepared by a convenient solution dispersion procedure, wherein the dispersion structure of LDH_NO3 in PAM was studied by X-ray diffraction, size distribution measurements and Tyndall effect. The nanocomposites exhibit excellent stabilities toward various environmental conditions such as heating, centrifugation and salt-tolerance. Moreover, in the whole process of drying and after the re-dissolution, the nanocomposites kept a uniform dispersion structure without any precipitation formation. Finally, the dynamic and steady rheological investigations were conducted. Nanoscale LDH_NO3 particles and layers were found to have drastic effects on the PAM solution rheological behaviour with an obvious gel-formation process at a low LDH content, and strong frequency dependence of viscosity at low frequencies.
Co-reporter:Zhuang Zhang, Guangming Chen, Hanfu Wang and Wentao Zhai
Journal of Materials Chemistry A 2015 - vol. 3(Issue 8) pp:NaN1654-1654
Publication Date(Web):2015/01/16
DOI:10.1039/C4TC02471K
A new strategy, i.e. interfacial adsorption-soft template polymerization, is developed to enhance polymer thermoelectric property. The obtained nanocomposite 3D interconnected architecture consisting of reduced graphene oxide (rGO) nanolayers sandwiched by polypyrrole (PPy) nanowires is directly confirmed by scanning and transmission electron microscopies. Moreover, the nanocomposites reveal significantly enhanced thermoelectric performance. At rGO:PPy ratio of 50 wt%, the nanocomposite power factor reaches ∼476.1 times that of pure PPy nanowires. Our results suggest that a greatly enhanced thermoelectric property for polymer nanocomposites can be achieved by a complex morphology design.
Co-reporter:Lirong Liang, Caiyan Gao, Guangming Chen and Cun-Yue Guo
Journal of Materials Chemistry A 2016 - vol. 4(Issue 3) pp:NaN532-532
Publication Date(Web):2015/12/14
DOI:10.1039/C5TC03768A
Recently, due to their unique advantages over inorganic materials, organic polymer thermoelectric (TE) materials have received considerable attention. However, most studies focus on TE performance enhancement. So far, little attention has been paid to large-area preparation, stretchability, super flexibility and mechanical stability, although these are the intrinsic advantages of polymer materials. Here we report for the first time large-area, stretchable, super flexible and mechanically stable TE films of polymer/carbon nanotube composites. Mechanically stretchable films with a diameter of ∼18 cm are achieved by common vacuum filtration, whose thicknesses and sizes can be conveniently adjusted. Despite direct observations of films under various deformations of bending, rolling or twisting, quantitative measurements of minimum bending radii (<0.6 mm) further confirm the super flexibility. More importantly, after mechanical bending or stretching, no obvious deterioration of TE performance is found. Our findings represent a novel direction of polymer TE materials, and will speed up their applications.
Co-reporter:Kongli Xu, Guangming Chen and Dong Qiu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 40) pp:NaN12399-12399
Publication Date(Web):2013/08/23
DOI:10.1039/C3TA12691A
A novel strategy via the convenient construction of a pie-like structure has been developed to prepare a poly(3,4-ethylenedioxythiophene)–reduced graphene oxide (PEDOT–rGO) nanocomposite with a greatly enhanced thermoelectric performance. Via a template-directed in situ polymerization, thick and uniform coatings of PEDOT layers were conveniently grown on both sides of the rGO nanosheet surfaces due to a strong π–π interfacial interaction. The nanocomposite exhibited a significantly enhanced thermoelectric performance at room temperature with a power factor of 5.2 ± 0.9 × 10−6 W m−1 K−2, greater than 13.3 times that of the PEDOT.
Co-reporter:Ziqiao Hu and Guangming Chen
Journal of Materials Chemistry A 2014 - vol. 2(Issue 33) pp:NaN13601-13601
Publication Date(Web):2014/06/16
DOI:10.1039/C4TA01590H
Water was used to replace the toxic organic solvent of formamide in preparation of the aqueous dispersions of layered double hydroxide/polyacrylamide (LDH/PAM) nanocomposites, which exhibited greatly enhanced rheological properties when compared to those of the neat PAM. First, the nanocomposite dispersions were prepared via a convenient in situ polymerization or solution mixing method, using water to exfoliate the LDH particles instead of formamide as used in the pioneer investigation. The LDH dispersion structure in the nanocomposite dispersion was demonstrated by X-ray diffraction and direct observation. Then, the rheological investigations including sol → gel transition, dynamic oscillatory frequency sweep and steady shear measurements were carried out. Subsequently, the rheological properties for the aqueous nanocomposite dispersions prepared by the two methods were compared. Finally, the mechanism of the enhancement of rheological properties (the moduli and viscosities) was discussed based on the LDH dispersion microstructure, network formation as well as interfacial interactions between PAM chains and LDH nanoparticles.
Co-reporter:Xincheng Hu, Guangming Chen, Xin Wang and Hanfu Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 42) pp:NaN20902-20902
Publication Date(Web):2015/09/29
DOI:10.1039/C5TA07381B
The thermoelectric performance of a conducting polymer is conveniently and effectively tuned by nanostructure evolution. The electrical conductivity, Seebeck coefficient and power factor follow the same sequence of bulk poly(3,4-ethylenedioxythiophene) (PEDOT) < globular nanoparticle < nanorod or ellipsoidal nanoparticle < nanotube < nanofibre. The molecular mechanism is studied by carrier mobility and concentration, the ordered structure of polymer chains, and the levels of doping and oxidation of PEDOT.
Co-reporter:Caiyan Gao and Guangming Chen
Journal of Materials Chemistry A 2016 - vol. 4(Issue 29) pp:NaN11306-11306
Publication Date(Web):2016/06/28
DOI:10.1039/C6TA03988J
Although organic polymer/inorganic particle composites with thermoelectric (TE) performance have witnessed rapid progress in recent years, previous studies mainly focused on a few classically conducting polymers. Schiff base polymers have various advantages such as their ease of preparation, versatile derivatives and adjustable complexation. Unfortunately, studies of Schiff base TE composites are very scarce. The only example reported so far is obtained via a two-step procedure, i.e. synthesis of monomer and subsequent polymerization. Here, we report a convenient one-pot preparation and the TE performances of a series of flexible composite films based on single-walled carbon nanotubes (SWCNTs) and a novel poly-Schiff base, which is achieved via a condensation reaction between glyoxal and p-phenylenediamine. Furthermore, the TE performance of the poly-Schiff base composites reported herein can be conveniently adjusted by chelating transition metal ions. The results reveal that both the preparation method and the poly-Schiff base/SWCNT mass ratio have important impacts on the composite TE performance. The electrical conductivities and the Seebeck coefficients for the physically mixed composites exhibit opposite variation tendencies with poly-Schiff base/SWCNT mass ratio, while the power factors increase with increasing mass ratio. At a poly-Schiff base/SWCNT mass ratio of 1:3, the physically mixed composite reaches the highest power factor of 77.7 ± 5.8 μW m−1 K−2. Finally, by chelating transition metal ions with 1,4-diazabuta-1,3-diene unit of poly-Schiff base, the TE performances of poly-Schiff base/transition metal/SWCNT composites are conveniently adjusted.
Co-reporter:Cuiping Yuan, Jinhao Zhang, Guangming Chen and Jiping Yang
Chemical Communications 2011 - vol. 47(Issue 3) pp:NaN901-901
Publication Date(Web):2010/11/15
DOI:10.1039/C0CC03198D
The effect of carbon nanotubes on polymer macromolecular orientation structure during stretching of syndiotactic polystyrene/carbon nanotube nanocomposite film was quantitatively studied for the first time by an infrared dichroism technique.
![BENZENE, 1,1'-[1,4-BUTANEDIYLBIS(OXY)]BIS[4-NONYL-](http://img.cochemist.com/ccimg/876400/876379-95-2.png)
![BENZENE, 1,1'-[1,4-BUTANEDIYLBIS(OXY)]BIS[4-NONYL-](http://img.cochemist.com/ccimg/876400/876379-95-2_b.png)
