Ionogel Materials for Fluid Control and Sensing in Microfluidic Devices

Abstract

Photo-responsive materials are of great interest as functional materials since actuation can be controlled by simple light irradiation, without physical contact, offering improvements in versatility during manifold fabrication, and control of actuation. We have investigated the potential use of spiropyran-modified ionogels, figure 1a, for controlling fluid within microfluidic channels. In particular, ionic liquids are rarely used in optical sensors in spite of their excellent chemical and thermal stabilities, low vapour pressure, high ionic conductivity and tuneable hydrophobic and hydrophilic nature. We have incorporated sensing moieties into ionogels for the generation of a barcode system based on microfluidics that monitors the pH of sweat generated during an exercise period in real time.