Fabrication of Hydrogel and Gas Permeable Membranes for FET Type Dissolved $CO_{2}$ Sensor by Photolithographic Method

사진식각법을 이용한 FET형 용존 $CO_{2}$ 센서의 수화젤막 및 가스 투과막 제작

  • Park, Lee-Soon (Department of Polymer Science, Faculty of Engineering, Kyungpook National University) ;
  • Kim, Sang-Tae (Department of Polymer Science, Faculty of Engineering, Kyungpook National University) ;
  • Koh, Kwang-Nak (Sensor Technology Research Center, Kyungpook National University)
  • 박이순 (경북대학교 고분자공학과) ;
  • 김상태 (경북대학교 고분자공학과) ;
  • 고광락 (경북대학교 센서기술연구소)
  • Published : 1997.05.31

Abstract

A field effect transistor(FET) type dissolved carbon dioxide($pCO_{2}$) sensor with a double layer structure of hydrogel membrane and $CO_{2}$ gas permeable membrane was fabricated by utilizing a $H^{+}$ ion selective field effect transistor(pH-ISFET) with Ag/AgCl reference electrode as a base chip. Formation of hydrogel membrane with photo-crosslinkable PVA-SbQ or PVP-PVAc/photosensitizer system was not suitable with the photolithographic process. Furthermore, hydrogel membrane on pH-ISFET base chip could be fabricated by photolithographic method with the aid of N,N,N',N'-tetramethyl othylenediarnine(TED) as $O_{2}$ quencher without using polyester film as a $O_{2}$ blanket during UV irradiation process. Photosensitive urethane acrylate type oligomer was used as gas permeable membrane on top of hydrogel layer. The FET type $pCO_{2}$ sensor fabricated by photolithographic method showed good linearity (linear calibration curve) in the range of $10^{-3}{\sim}10^{0}\;mol/{\ell}$ of dissolved $CO_{2}$ in aqueous solution with high sensitivity.

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