Photopatternable Polymeric Membranes for Optical Oxygen Sensors

A new class of optical oxygen sensor that can be photopatternable by traditional UV lithography is presented. They are fabricated using photopatternable spin-on silicone (polydimethylsiloxane, PDMS) with oxygen sensitive luminescent dyes. It has a good adhesion property and can be applied on glass or on photopolymer (SU-8) without any additional surface treatments. The optimum mixture composition for patternable oxygen sensitive membranes is investigated and its optical properties are characterized. Proof-of-concepts for two applications, intensity-based oxygen sensing with SU-8 based structure and self-calibration fluidic oxygen sensor, are described. These photopatternable optical membranes will find many applications wherever small patterns of oxygen sensitive membranes are required.

I. Introduction

Determination of oxygen concentration is very important in many environmental, medical, and clinical applications. One popular type of oxygen sensor is the optical oxygen sensor because they offer a lot of advantages compared to its electrochemical counterpart, such as no electrical interference, no oxygen consumption, and compatibility with imaging. Most of the optical sensors are based on the principle that oxygen quenches the luminescence emitted from the luminescent dyes which are immobilized in an oxygen permeable membrane such as silicone [1]–[4].