Recent advances in graphene based polymer composites

Graphene has emerged as a subject of enormous scientific interest due to its exceptional electron transport, mechanical properties, and high surface area. When incorporated appropriately, these atomically thin carbon sheets can significantly improve physical properties of host polymers at extremely small loading. We first review production routes to exfoliated graphite with an emphasis on top-down strategies starting from graphite oxide, including advantages and disadvantages of each method. Then solvent- and melt-based strategies to disperse chemically or thermally reduced graphene oxide in polymers are discussed. Analytical techniques for characterizing particle dimensions, surface characteristics, and dispersion in matrix polymers are also introduced. We summarize electrical, thermal, mechanical, and gas barrier properties of the graphene/polymer nanocomposites. We conclude this review listing current challenges associated with processing and scalability of graphene composites and future perspectives f...

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Graphene/Polymer Nanocomposites

Composite films of chemically converted graphene (CCG) and polyaniline nanofibers (PANI-NFs) were prepared by vacuum filtration the mixed dispersions of both components. The composite film has a layered structure, and PANI-NFs are sandwiched between CCG layers. Furthermore, it is mechanically stable and has a high flexibility; thus, it can be bent into large angles or be shaped into various desired structures. The conductivity of the composite film containing 44% CCG (5.5 × 102 S m−1) is about 10 times that of a PANI-NF film. Supercapacitor devices based on this conductive flexible composite film showed large electrochemical capacitance (210 F g−1) at a discharge rate of 0.3 A g−1. They also exhibited greatly improved electrochemical stability and rate performances.

Supercapacitors Based on Flexible Graphene/Polyaniline Nanofiber Composite Films

Progress in preparation, processing and applications of polyaniline

Keywords: Fragmentation Chain-Transfer ; Self-Assembled Monolayers ; Walled Carbon Nanotubes ; Well-Defined Polymer ; Nitroxide-Mediated Polymerization ; Block-Copolymer Brushes ; Poly(Methyl Methacrylate) Brushes ; Transfer Raft Polymerization ; Quartz-Crystal Microbalance ; Poly(Acrylic Acid) Brushes Reference EPFL-REVIEW-148464doi:10.1021/cr900045aView record in Web of Science Record created on 2010-04-23, modified on 2017-05-10

Polymer Brushes via Surface-Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

Development of fluorescent imaging probes is an important topic of research for the early diagnosis of cancer. Based on the difference between the cellular environment of tumor cells and normal cells, several "smart" fluorescent probe has been developed. In this work, we developed a glycopolymer functionalized Förster resonance energy transfer (FRET) based fluorescent sensor, which can monitor the pH change in cellular system. One-pot sequential RAFT polymerization technique was employed to synthesize fluorescent active triblock glycopolymer that can undergo FRET change on the variation of pH. A FRET pair, fluorescein o-acrylate (FA) and 7-amino-4-methylcoumarin (AMC) was linked via a pH-responsive polymer poly [2-(diisopropylamino)ethyl methacrylate] (PDPAEMA), which can undergo reversible swelling/deswelling under acidic/neutral condition. The presence of glycopolymer segment, provided stability, water solubility and specificity towards cancer cells. The cellular FRET experiments on cancer cells (MDA MB 231) and normal cells (3T3 fibroblast cells) demonstrated that the material is capable of distinguishing cells as a function of pH change. This article is protected by copyright. All rights reserved.

Glycopolymer Decorated pH-Dependent Ratiometric Fluorescent Probe Based on Förster Resonance Energy Transfer for the Detection of Cancer Cells.

Multifunctional elastomers have gained tremendous attention in the material research community. In this study, an epoxy functionalized elastomer poly(ethylene-co-vinyl acetate-co-glycidyl methacrylate) (EVA-GMA) that is commercially available was modified with dynamic covalent chemistry to make it self-healable and recyclable, as well as to investigate its adhesive properties. EVA-GMA was modified to a furfuryl-appended diene elastomer (FA-EVA-GMA) and subsequently cross-linked with bifunctional 1,2,4-triazoline-3,5-dione (bis-TAD) and bismaleimide (BMI) derivatives via electrophilic substitution (ES) and Diels-Alder (DA) chemistry, respectively. The ES modification of the elastomer was ambiently completed using bis-TAD, whereas its maleimide modification required elevated conditions (65 °C) with a longer time of 24 h. The tensile study showed a remarkable improvement in the mechanical strength upon cross-linking the elastomers. The differential scanning calorimetry (DSC) analysis elucidated the thermoreversible characteristics of both the ES and DA-derived networks, showing the cleavage of ES and DA conjugates at 135 °C (retro-ES) and 140 °C (retro-DA), respectively. The cross-linked elastomers exhibited significant self-healing characteristics (with a healing efficiency of ≈ 88%) and monitored using an optical microscope and tensile analysis. Interestingly, the bis-TAD-derived and bismaleimide functionalized EVA-elastomer showed excellent adhesive properties toward the metal surfaces, as analyzed via lap shear test. 

Functional self‐healable
 EVA
 elastomers based on reversible covalent networks: A potential new class of epoxy‐based specialty adhesives

Self-healable functional polymers based on Diels–Alder ‘click chemistry’ involving substituted furan and triazolinedione derivatives: a simple and very fast approach

Polydimethylsiloxane based polyurethane and its composite with layered double hydroxide: Synthesis and its thermal properties

The effect of ionic liquids on the reversible addition-fragmentation chain transfer (RAFT) polymerization mediated by a visible-light-induced photoiniferter mechanism was investigated. N,N-Dimethyl acrylamide was polymerized by photoiniferter polymerization in 1-ethyl-3-methylimidazolium ethylsulfate [EMIM][EtSO4] ionic liquid. We observed a considerable increase in the polymerization rate constants in ionic liquids (ILs), as well as in the mixed solvent of water and the IL, compared to those observed with water alone as the solvent. To demonstrate the robustness of the process, block copolymers with varying block ratios were synthesized with precise control over their molecular weight and mass dispersity (Đ). The very high chain-end fidelity provided by the photoiniferter polymerization in IL was described by using MALDI-ToF MS analysis.

Nikhil K. Singha

Papers

Glycopolymer Decorated pH-Dependent Ratiometric Fluorescent Probe Based on Förster Resonance Energy Transfer for the Detection of Cancer Cells.

Functional self‐healable EVA elastomers based on reversible covalent networks: A potential new class of epoxy‐based specialty adhesives

Self-healable functional polymers based on Diels–Alder ‘click chemistry’ involving substituted furan and triazolinedione derivatives: a simple and very fast approach

Polydimethylsiloxane based polyurethane and its composite with layered double hydroxide: Synthesis and its thermal properties

Visible Light-Accelerated Photoiniferter Polymerization in Ionic Liquid.