Applied Surface Science, Vol.336, 85-88, 2015
Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications
A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar+-laser at lambda = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 mu m, functionalized surface areas with diameters down to 5 pin are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed. (C) 2014 Published by Elsevier B.V.
Keywords:Fuel cell;Bipolar plate;Photothermal laser processing;Functionalization;Wettability;Water management