Use of polyethylene glycol coatings for optical fibre humidity sensing

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Acikgoz S., Bilen B., Demir M. M., Menceloglu Y. Z., Skarlatos Y., Aktas G., ...Daha Fazla

OPTICAL REVIEW, cilt.15, sa.2, ss.84-90, 2008 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 15 Sayı: 2
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1007/s10043-008-0012-1
  • Dergi Adı: OPTICAL REVIEW
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.84-90
  • Anahtar Kelimeler: humidity, sensors, plastic fibre, optics, polyethylene glycol, WAVE-GUIDES, SENSOR, FILMS, SORPTION, AIR
  • Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
  • Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Hayır

Özet

Humidity induced change in the refractive index and thickness of the polyethylene glycol (PEG) coatings are in situ investigated for a range from 10 to 95%, using an optical waveguide spectroscopic technique. It is experimentally demonstrated that, upon humidity change, the optical and swelling characteristics of the PEG coatings can be employed to build a plastic fibre optic humidity sensor. The sensing mechanism is based on the humidity induced change in the refractive index of the PEG film, which is directly coated onto a polished segment of a plastic optical fibre with dip-coating method. It is observed that PEG, which is a highly hydrophilic material, shows no monotonic linear response to humidity but gives different characteristics for various ranges of humidity levels both in index of refraction and in thickness. It undergoes a physical phase change from a semi-crystal line structure to a gel one at around 80% relative humidity. At this phase change point, a drastic decrease occurs in the index of refraction as well as a drastic increase in the swelling of the PEG film. In addition, PEG coatings are hydrogenated in a vacuum chamber. It is observed that the hydrogen has a preventing effect on the humidity induced phase change in PEG coatings. Finally, the possibility of using PEG coatings in construction of a real plastic fibre optic humidity sensor is discussed. (C) 2008 The Optical Society of Japan.