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NUSNNI Seminar Series 2003 No.1
Time: July 15, 2003, 11:00-12:00pm
Venue: Physics Conference Rm (S13-M01-15)
Speaker: Dr Paul Pigram (Centre for Materials and Surface
Science, and Department of
Physics La Trobe University, Melbourne Victoria 3086 Australia)
Title: Micro-patterning of fluoropolymer surfaces for electronic
and biomaterials applications
Abstract:
A brief introduction of the activities and resources of the Centre
for Materials and Surface Science at La Trobe University will be
presented focussing on electron spectroscopy and secondary ion mass
spectrometry. A three year project investigating micro-patterning
of fluoropolymers via the micro-contact printing (¦ÌCP) pathway,
in collaboration with Professor E.T. Kang, National University of
Singapore, commenced in 2002. The principal aim of this program
is to achieve convergence between controlled fluoropolymer surface
modification technologies and micro-patterning of polymer surfaces
using ¦ÌCP. Ultimately, flexible device structures with sensor and
other electronic applications will be produced.
Work to date has focussed on optimising the multilayer films required
to produce a polypyrrole-based ¦ÌCP sensor. Polypyrrole (PPy) films
doped with dodecylbezenesulfonic acid (DBSA) on copper substrates
have been prepared using electrochemical pre-treatment of the copper
surface. Formation of a passivating oxide at the Cu surface impedes
substrate dissolution without preventing pyrrole electropolymerisation;
there have been only two previous reports of PPy deposition on Cu
using alternative pathways. Film formation and interfacial phenomena
have been explored using XPS, TOF-SIMS and cyclic voltammetry.
Multilayer films have been created for sensor construction comprising
PPy deposited on PTFE via an electroless Cu interlayer. Fluoropolymer
substrates were Ar plasma-treated, modified by silanisation and
activated by PdCl2 for electroless Cu deposition. The commonly used
SnCl2 sensitisation stage in electroless deposition was eliminated
to create a tin-free process. Attention has recently shifted to
introducing ¦ÌCP patterning at key stages of the multilayer deposition
pathway. Initial XPS, TOF-SIMS and contact angle results will be
presented arising from the optimisation of surface chemistries and
micro-contact printing methodologies. Factors determining minimum
feature dimensions and adhesion characteristics are currently under
investigation.
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