A pinboard by
Nick Adamson

PhD student, The University of Melbourne


Microstructured piezoelectric materials to power thin film and flexible electronic devices.

My research aims to create tiny pillars of a polymer able to generate electricity when bent (piezoelectric), which is smaller than the width of a human hair, by using a technique called 3D-microprinting. Using pressure to deposit droplets through tiny nozzles in 3D-printers can help orient the polymer chains to obtain a high piezoelectric coefficient compared to standard film casting techniques. This flexible, thin and transparent polymer can use the piezoelectric effect to generate electricity when it is bent, folded, stretched, or deformed in any other way. The micropillars play a key role, as they have a much higher surface area than a flat sheet of polymer, which further increases their electrical output. These microstructures can be used within an array of next-generation applications including generating electricity in smart roads and smart clothing, flexible electronics that can self-charge on the go, as well as a variety of self-powered sensors ranging from the detection of toxic gases through to monitoring heart rate and breathing rate.


Multi-functional poly(vinylidene fluoride) graft copolymers

Abstract: Poly(vinylidene fluoride) (PVDF) is known for its biocompatibility, piezo and pyro-electricity, and membrane forming capability. In order to tune its properties, modification through grafting from approach by atom transfer radical polymerization (ATRP) is preferred. Hydrophilic polymers like poly(ethylene glycol) methacrylate, poly(methacrylic acid), poly(dimethylaminoethyl methacrylate) (PDMAEMA), and so forth have been anchored from PVDF backbone in order to make permeation of water molecules through the PVDF based membranes. The successful solution grafting of PDMAEMA chains from PVDF backbone by ATRP resulted appreciable graft conversion and hence its bulk properties showed a significant change. This water soluble graft copolymer shows incredible mechanical and adhesive properties. PVDF-g-poly(n-butyl methacrylate) generates honey-comb porous film using “breath figure” technique. Recently, they have used further improvement of grafting where model ATRP initiators are anchored using atom transfer radical coupling and used them as macroinitiators for grafting. This approach simplified the grafting reactions even more and enabled successful grafting of a large number of monomers under relatively less drastic conditions with appreciable conversion compared with the previous conditions. This technique has resulted interesting solution properties, ion and electron conducting PVDF, antifouling membrane, super glue and super tough materials, capable of generating metal nanoparticles tunable with pH and temperature. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017

Pub.: 04 Jun '17, Pinned: 25 Aug '17

High-Performance Piezoelectric Nanogenerators with Imprinted P(VDF-TrFE)/BaTiO3 Nanocomposite Micropillars for Self-Powered Flexible Sensors

Abstract: Piezoelectric nanogenerators with large output, high sensitivity, and good flexibility have attracted extensive interest in wearable electronics and personal healthcare. In this paper, the authors propose a high-performance flexible piezoelectric nanogenerator based on piezoelectrically enhanced nanocomposite micropillar array of polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE))/barium titanate (BaTiO3) for energy harvesting and highly sensitive self-powered sensing. By a reliable and scalable nanoimprinting process, the piezoelectrically enhanced vertically aligned P(VDF-TrFE)/BaTiO3 nanocomposite micropillar arrays are fabricated. The piezoelectric device exhibits enhanced voltage of 13.2 V and a current density of 0.33 µA cm−2, which an enhancement by a factor of 7.3 relatives to the pristine P(VDF-TrFE) bulk film. The mechanisms of high performance are mainly attributed to the enhanced piezoelectricity of the P(VDF-TrFE)/BaTiO3 nanocomposite materials and the improved mechanical flexibility of the micropillar array. Under mechanical impact, stable electricity is stably generated from the nanogenerator and used to drive various electronic devices to work continuously, implying its significance in the field of consumer electronic devices. Furthermore, it can be applied as self-powered flexible sensor work in a noncontact mode for detecting air pressure and wearable sensors for detecting some human vital signs including different modes of breath and heartbeat pulse, which shows its potential applications in flexible electronics and medical sciences.

Pub.: 28 Apr '17, Pinned: 25 Aug '17