Title: Polymer brushes for improvement of dry adhesion in biomimetic dry adhesives

Authors: Omer Javed Chaudhary; Emilio Calius; John V. Kennedy; Jadranka Travas-Sejdic

Addresses: Polymer Electronics Research Centre (PERC), University of Auckland, Private Bag 92019, Auckland, 1010, New Zealand ' Callaghan Innovation, 24 Balfour Road, Auckland 1140, New Zealand ' National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, 5010 New Zealand; MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand ' Polymer Electronics Research Centre (PERC), University of Auckland, Private Bag 92019, Auckland, 1010, New Zealand; MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand

Abstract: Geckos' feet are extensively micro-structured, enabling geckos to adhere strongly to most surfaces and perform various manoeuvres even while upside down. Inspired by the structure of geckos' feet, a large number of biomimetic dry adhesives have been reported. Polymers brushes can offer a molecular scale attachment to surfaces; here we studied the effect of polymer brushes on adhesion. Atom transfer radical polymerisation (ATRP) was used to graft poly(butyl acrylate) brushes on a poly(dimethylsiloxane) (PDMS) surface using a surface-bound ATRP initiator. Growth of the polymer brushes was verified by ATR-FTIR spectroscopy. To study the effect of polymer brushes, the samples were tested for pull-off adhesion with and without the grafted chains. The polymer-grafted PDMS showed an increase in adhesion compared to unmodified PDMS. Results suggest that carefully selected polymer brushes will enhance the adhesion of microstructured biomimetic adhesives.

Keywords: dry adhesion; geckos; gecko adhesion; poly(dimethylsiloxane); PDMS; ATRP; atom transfer radical polymerisation; polymer brushes; poly(butyl acrylate); biomimetic dry adhesives; nanotechnology; microstructure.

DOI: 10.1504/IJNT.2014.060586

International Journal of Nanotechnology, 2014 Vol.11 No.5/6/7/8, pp.636 - 644

Published online: 20 Apr 2014 *

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