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Full-Text Articles in Physical Sciences and Mathematics

Polypyrrole Doped With Redox-Active Poly(2-Methoxyaniline-5-Sulfonic Acid) For Lithium Secondary Batteries, Yang Yang, Caiyun Wang, Syed A. Ashraf, Gordon G. Wallace Mar 2014

Polypyrrole Doped With Redox-Active Poly(2-Methoxyaniline-5-Sulfonic Acid) For Lithium Secondary Batteries, Yang Yang, Caiyun Wang, Syed A. Ashraf, Gordon G. Wallace

Gordon Wallace

Polypyrrole is a promising electrode material for flexible/bendable energy storage devices due to its inherent fast redox switching, mechanical flexibility, easy processability and being environmentally benign. However, its low attainable capacity limits its practical applications. Here, we synthesise a polypyrrole/poly(2-methoxyaniline-5-sulfonic acid) (PPy/PMAS) composite by incorporating redox-active PMAS into a PPy matrix via an electropolymerization method. For comparison, polypyrrole containing the electrochemically inert dopant p-toluenesulfonate (PPy-pTS) was prepared under the same conditions. The resultant PPy/PMAS film shows greatly improved electrochemical properties by harnessing the contribution from PMAS, i.e. higher specific capacity, better rate capability and improved cycling stability when used as …


Quantifying Fibronectin Adhesion With Nanoscale Spatial Resolution On Glycosaminoglycan Doped Polypyrrole Using Atomic Force Microscopy, Amy Gelmi, Michael J. Higgins, Gordon G. Wallace Mar 2014

Quantifying Fibronectin Adhesion With Nanoscale Spatial Resolution On Glycosaminoglycan Doped Polypyrrole Using Atomic Force Microscopy, Amy Gelmi, Michael J. Higgins, Gordon G. Wallace

Gordon Wallace

The interaction of ECM proteins is critical in determining the performance of materials used in biomedical applications such as tissue regeneration, implantable bionics and biosensing. Methods: To improve our understanding of ECM protein–conducting polymer interactions, we have used Atomic Force Microscopy (AFM) to elucidate the interactions of fibronectin (FN) on polypyrrole (PPy) doped with different glycosaminoglycans. Results: We were able to classify four main types of FN interactions, including those related to 1) non-specific adhesion, 2) protein unfolding and subsequent unbinding from the surface, 3) desorption and 4) interactions with no adhesion. FN adhesion on PPy/hyaluronic acid showed a significantly …


Surface Properties And Interaction Forces Of Biopolymer-Doped Conductive Polypyrrole Surfaces By Atomic Force Microscopy, Jani M. Pelto, Suvi P. Haimi, Aliisa S. Siljander, Susanna S. Miettinen, Kirsi M. Tappura, Michael J. Higgins, Gordon G. Wallace Mar 2014

Surface Properties And Interaction Forces Of Biopolymer-Doped Conductive Polypyrrole Surfaces By Atomic Force Microscopy, Jani M. Pelto, Suvi P. Haimi, Aliisa S. Siljander, Susanna S. Miettinen, Kirsi M. Tappura, Michael J. Higgins, Gordon G. Wallace

Gordon Wallace

Surface properties and electrical charges are critical factors elucidating cell interactions on biomaterial surfaces. The surface potential distribution and the nanoscopic and microscopic surface elasticity of organic polypyrrole-hyaluronic acid (PPy-HA) were studied by atomic force microscopy (AFM) in a fluid environment in order to explain the observed enhancement in the attachment of human adipose stem cells on positively charged PPy-HA films. The electrostatic force between the AFM tip and a charged PPy-HA surface, the tip-sample adhesion force, and elastic moduli were estimated from the AFM force curves, and the data were fitted to electrostatic double-layer and elastic contact models. The …


Electrically Conductive Coatings Of Nickel And Polypyrrole/Poly(2- Methoxyaniline-5-Sulfonic Acid) On Nylon Lycra® Textiles, B C. Kim, P C. Innis, Gordon G. Wallace, C T.J Low, F C. Walsh, W J. Cho, K H. Yu Mar 2014

Electrically Conductive Coatings Of Nickel And Polypyrrole/Poly(2- Methoxyaniline-5-Sulfonic Acid) On Nylon Lycra® Textiles, B C. Kim, P C. Innis, Gordon G. Wallace, C T.J Low, F C. Walsh, W J. Cho, K H. Yu

Gordon Wallace

Woven nylon Lycra® has been coated with finely-divided electroless nickel-phosphorus, polypyrrole and electroless nickel/polypyrrole to produce flexible and electrically conductive textiles. The coated textiles were tested for their electrochemical activity, electrical resistivity and resistivity in response to mechanical strain. Pre-dyeing the textile with poly(2-methoxyaniline-5-sulfonic acid) (PMAS) prior to electroless metallization by electroless nickel and via chemical polymerization of polypyrrole was found to be beneficial in enhancing the resultant coating as well as stabilizing surface resistance responses when exposed to a wide range of strain. The mass gain due to the nickel coating was found to increase linearly with deposition time. …


Flexible Cellulose Based Polypyrrole-Multiwalled Carbon Nanotube Films For Bio-Compatible Zinc Batteries Activated By Simulated Body Fluids, Sha Li, Zai Ping Guo, Cai Yun Wang, Gordon G. Wallace, Hua-Kun Liu Mar 2014

Flexible Cellulose Based Polypyrrole-Multiwalled Carbon Nanotube Films For Bio-Compatible Zinc Batteries Activated By Simulated Body Fluids, Sha Li, Zai Ping Guo, Cai Yun Wang, Gordon G. Wallace, Hua-Kun Liu

Gordon Wallace

This work aims to develop biocompatible non-toxic materials for implantable bio-electronic cells. Polypyrrole (PPy)–carbon nanotube (CNT) composites with varied ratios of PPy to CNTs were chemically synthesized and used as cathodes with the support of cellulose paper. Zinc foil was used as the anode material due to its non-toxicity and moderate dissolution rate in aqueous solutions. Simulated body fluids (SBFs) with various protein concentrations were applied as electrolytes in this battery system. The PPy–CNT|Zn cell is capable of being discharged up to 24.5 hours at a current density of 60 μA cm−2 in a protein free SBF. The batteries have …


Surface Modification Of Polypyrrole/Biopolymer Composites For Controlled Protein And Cellular Adhesion, Paul J. Molino, Binbin Zhang, Gordon G. Wallace, Timothy Hanks Mar 2014

Surface Modification Of Polypyrrole/Biopolymer Composites For Controlled Protein And Cellular Adhesion, Paul J. Molino, Binbin Zhang, Gordon G. Wallace, Timothy Hanks

Gordon Wallace

The ability to control the interaction between proteins and cells with biomaterials is critical for the effective application of materials for a variety of biomedical applications. Herein, the surface modification of the biological dopant dextran sulphate-doped polypyrrole (PPy-DS) with poly(ethylene glycol) to generate a biomaterial interface that is highly resistant to protein and cellular adhesion is described. Thiolated poly(ethylene glycol) (PEG-thiol) was covalently bound to PPy-DS backbone via a thiol-ene reaction. The surface resistance to an extracellular matrix protein fibronectin increased with increasing molecular weight and concentration of PEG-thiol, and was further optimised via increasing the reaction temperature and the …


Intrinsically Stretchable Supercapacitors Composed Of Polypyrrole Electrodes And Highly Stretchable Gel Electrolyte, Chen Zhao, Caiyun Wang, Zhilian Yue, Kewei Shu, Gordon G. Wallace Mar 2014

Intrinsically Stretchable Supercapacitors Composed Of Polypyrrole Electrodes And Highly Stretchable Gel Electrolyte, Chen Zhao, Caiyun Wang, Zhilian Yue, Kewei Shu, Gordon G. Wallace

Gordon Wallace

There has been an emerging interest in stretchable power sources compatible with flexible/wearable electronics. Such power sources must be able to withstand large mechanical strains and still maintain function. Here we report a highly stretchable H3PO4-poly(vinyl alcohol) (PVA) polymer electrolyte obtained by optimizing the polymer molecular weight and its weight ratio to H3PO4 in terms of conductivity and mechanical properties. The electrolyte demonstrates a high conductivity of 3.4 x 10-3 S cm-1, and a high fracture strain at 410% elongation. It is mechanically robust with a tensile strength of 2 MPa and a Young's modulus of 1 MPa, and displays …


Evaluation Of Encapsulating Coatings On The Performance Of Polypyrrole Actuators, Sina Naficy, Nicholas Stoboi, Philip G. Whitten, Geoffrey M. Spinks, Gordon G. Wallace Mar 2014

Evaluation Of Encapsulating Coatings On The Performance Of Polypyrrole Actuators, Sina Naficy, Nicholas Stoboi, Philip G. Whitten, Geoffrey M. Spinks, Gordon G. Wallace

Gordon Wallace

Conjugated polymer actuators are electroactive materials capable of generating force and movement in response to an applied external voltage. Many potential biomedical and industrial applications require these actuators to operate in a liquid environment. However, immersion of uncoated conducting polymer actuators in non-electrolyte liquids greatly reduces their operating lifetime. Here, we demonstrate the use of spray coating as an effective and simple method to encapsulate polypyrrole (PPy) tri-layer bending actuators. Poly(styrene-b-isobutylene-b-styrene) (SIBS) was used as an encapsulating, compliant spray coating on PPy actuators. A significant enhancement in actuator lifetime in both air and water was observed by encapsulating the actuators. …


Electrochemically Synthesized Stretchable Polypyrrole/Fabric Electrodes For Supercapacitor, Binbin Yue, Caiyun Wang, Xin Ding, Gordon G. Wallace Mar 2014

Electrochemically Synthesized Stretchable Polypyrrole/Fabric Electrodes For Supercapacitor, Binbin Yue, Caiyun Wang, Xin Ding, Gordon G. Wallace

Gordon Wallace

Wearable electronics offer the combined advantages of both electronics and fabrics. Being an indispensable part of these electronics, lightweight, stretchable and wearable power sources are strongly demanded. Here we describe a daily-used cotton fabric coated with polypyrrole as electrode for stretchable supercapacitors. Polypyrrole was synthesized on the Au coated fabric via an electrochemical polymerization process with p-toluenesulfonic acid (p-TS) as dopant from acetonitrile solution. This material was characterized with FESEM, tensile stress, and studied as a supercapacitor electrode in 1.0 M NaCl. This conductive textile electrode can sustain up to 140% strain without electric failure. It delivers a high specific …


A Novel Codoping Approach For Enhancing The Performance Of Polypyrrole Cathode In A Bioelectric Battery, Yang Yang, Caiyun Wang, Chunming Zhang, Dan Wang, Dannong He, Gordon G. Wallace Jan 2014

A Novel Codoping Approach For Enhancing The Performance Of Polypyrrole Cathode In A Bioelectric Battery, Yang Yang, Caiyun Wang, Chunming Zhang, Dan Wang, Dannong He, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

A conducting polymer (CP) based bioelectric battery provides a promising alternative to commercial lithium batteries to drive biomedical devices. However, the low power density limits practical application. Here, we synthesize a polypyrrole (PPy)/anthraquinone sulfonate (AQS)/reduced graphene oxide (r-GO) composite via a facile electrochemical route, and use this as a novel cathode material for bioelectric batteries. The presence of r-GO significantly enhanced the electrochemical properties of PPy and led to greatly improved cell performance compared to that of PPy/AQS. The resultant PPy/AQS/r-GO composite delivered a maximum power density of 6240.5 mW m(-2), 14.2 times higher than that of PPy/p-toluenesulfonate (pTS) as …


Novel Germanium/Polypyrrole Composite For High Power Lithium-Ion Batteries, Xuanwen Gao, Wenbin Luo, Chao Zhong, David Wexler, Shulei Chou, Hua-Kun Liu, Zhicong Shi, Guohua Chen, Kiyoshi Ozawa, Jiazhao Wang Jan 2014

Novel Germanium/Polypyrrole Composite For High Power Lithium-Ion Batteries, Xuanwen Gao, Wenbin Luo, Chao Zhong, David Wexler, Shulei Chou, Hua-Kun Liu, Zhicong Shi, Guohua Chen, Kiyoshi Ozawa, Jiazhao Wang

Australian Institute for Innovative Materials - Papers

Nano-Germanium/polypyrrole composite has been synthesized by chemical reduction method in aqueous solution. The Ge nanoparticles were directly coated on the surface of the polypyrrole. The morphology and structural properties of samples were determined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Thermogravimetric analysis was carried out to determine the polypyrrole content. The electrochemical properties of the samples have been investigated and their suitability as anode materials for the lithium-ion battery was examined. The discharge capacity of the Ge nanoparticles calculated in the Ge-polypyrrole composite is 1014 mAh g-1 after 50 cycles at 0.2 C rate, which is …


Mechanically Strong High Performance Layered Polypyrrole Nano Fibre/Graphene Film For Flexible Solid State Supercapacitor, Sha Li, Chen Zhao, Kewei Shu, Caiyun Wang, Zaiping Guo, Gordon G. Wallace, Hua-Kun Liu Jan 2014

Mechanically Strong High Performance Layered Polypyrrole Nano Fibre/Graphene Film For Flexible Solid State Supercapacitor, Sha Li, Chen Zhao, Kewei Shu, Caiyun Wang, Zaiping Guo, Gordon G. Wallace, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Paper like flexible electrode becomes one of the most important research objects recently in request of the fast expanding market of portable electronics. Flexible solid state supercapacitors are shortlisted as one of the most promising energy devices to power electronics with medium to high power density requirements. In this work, we developed a simple but effective way to produce a mechanically strong and electrochemically active RGO/polypyrrole (PPy) fibre paper. A well-bedded microstructure was created with interlaced polypyrrole fibres evenly distributed between the graphene layers. Such microstructure can create enormous amount of pores and therefore provides larger interfaces for charge carrier …


One-Step Synthesis Of Graphene/Polypyrrole Nanofiber Composites As Cathode Material For A Biocompatible Zinc/Polymer Battery, Sha Li, Kewei Shu, Chen Zhao, Caiyun Wang, Zaiping Guo, Gordon G. Wallace, Hua-Kun Liu Jan 2014

One-Step Synthesis Of Graphene/Polypyrrole Nanofiber Composites As Cathode Material For A Biocompatible Zinc/Polymer Battery, Sha Li, Kewei Shu, Chen Zhao, Caiyun Wang, Zaiping Guo, Gordon G. Wallace, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

The significance of developing implantable, biocompatible, miniature power sources operated in a low current range has become manifest in recent years to meet the demands of the fast-growing market for biomedical microdevices. In this work, we focus on developing high-performance cathode material for biocompatible zinc/polymer batteries utilizing biofluids as electrolyte. Conductive polymers and graphene are generally considered to be biocompatible and suitable for bioengineering applications. To harness the high electrical conductivity of graphene and the redox capability of polypyrrole (PPy), a polypyrrole fiber/graphene composite has been synthesized via a simple one-step route. This composite is highly conductive (141 S cm …


Optimization Of The Sequential Polymerization Synthesis Method For Polypyrrole Films, Danial Sangian, Wen Zheng, Geoffrey M. Spinks Jan 2014

Optimization Of The Sequential Polymerization Synthesis Method For Polypyrrole Films, Danial Sangian, Wen Zheng, Geoffrey M. Spinks

Australian Institute for Innovative Materials - Papers

Polypyrrole (PPy) is widely used as an electroactive material and is most often synthesized using electrochemical polymerization. Recently, a new electropolymerization method [1] was introduced that involved preparing the PPy as a sequential series of electrodeposited layers with solvent washing in between each deposited layer. This method enabled high quality PPy free-standing films to be prepared in a relatively short time. The purpose of the present study was to investigate the effect of the polymerization current density on the mechanical and electrical properties of the sequentially polymerized (SEP) PPy films. It was found that a low current density (0.1 mA/cm2) …