Authors: K-C Chen, A.M. Wo and Y-F Chen
Affilation: National Taiwan University, Taiwan
Pages: 732 - 735
Keywords: PDMS (polydimethylsiloxane), transmission spectrum, mid-infrared FTIR spectroscopy, secondary structure of proteins, protein characterization
Infrared (IR) spectroscopy has been an important tool to characterize secondary structure of proteins for decades. To extend PDMS-based micro-device into spectroscopic characterization of proteins for structural study, the transmission spectrum of PDMS over the mid-IR range must be quantified. This work is the first, to the best knowledge of the authors, to measure the mid-IR transmission spectrum of PDMS (Dow Corning Sylgard 184). Moreover, effects of fabrication and measurement factors on maximum transmission rates are considered. One of the two transmission bands has maximum transmission rate 65%, where 85% of the band with transmission rate exceeds 60%. The maximum transmission rate has strong dependence, among other factors tested, on the mixing ratio of the base to the curing agent of PDMS pre-polymer. The range of maximum transmission rate of PDMS covers 64%-99.8% with mixing ratio of the two parts varied from 8:1 to 12:1. Hence, PDMS material can be tuned to provide necessary characteristic of window material in the wavenumbers range of 2490-2231 cm^-1, which might be used to determine molecular structure.