Preparation methods of alginate micro-hydrogel particles and evaluation of their electrophoresis behavior for possible electronic paper ink application

Abstract

For the purpose of an electronic paper application, alginateCa hydrogel particles having a diameter of a few micrometers used with Titanium Black (TB), which has a diameter of ∼ 1μm, for visualization purposes were prepared by mixing an aqueous sodium alginate solution with TB into an aqueous CaCl 2 solution. In order to increase their absolute zeta potential |ζ|for demonstrating good electric responsive behavior, micro-hydrogel particles were rinsed instantaneously by different concentrations of Na 2C3 solution. Through this procedure, the absolute value of the zeta potential in pure water increased from |ζ|=1.3mV for the minimum value to |ζ| = 73mV for the maximum value with an upon increasing Na2CO3 concentration. Micro-hydrogel particles were set between electrodes in pure water, their electro-responsive behavior was examined under an applied electric field and their position was analyzed using an optical microscopy. It was found that micro-hydrogel particles with a high absolute zeta potential |ζ|could oscillate from the anode to the cathode with a corresponding frequency, and threshold absolute zeta potential |ζ| was found to be between 1.3 and 39mV. © 2010 The Society of Polymer Science, Japan (SPSJ) All rights reserved.