LAUSR

Polydimethylsiloxane (PDMS) is a well-known material used in making microfluidic devices through soft lithography. PDMS strongly absorbs infrared (IR) light in the mid infrared region, which can be alleviated by using thin-film PDMS devices. However, IR detection with PDMS devices usually requires an IR-transparent backbone material. Here, we report a microfluidic system using a 160 µm PDMS thin-film device (50-µm path length) without a supporting backbone for IR spectroelectrochemistry (IR-SEC). The PDMS device is assembled with four layers: microchannel-supporting window, microchannel thin film, electrode-embedded thin film, and electrode-supporting window. In this work, mapping of ferrocyanide oxidation was investigated under an IR microscope. An electrochemical reaction, occurring between the working and counter electrodes, was observed clearly. Moreover, the electron-transfer process of ferrocyanide oxidation was investigated from the IR absorbance spectrum. This mapping study demonstrates that the r...