Effect of thickness on the dielectric properties and glass transition of plasma poly(ethylene oxide) thin films

Yakut S., Ulutas K., Deger D.

MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS, cilt.104, 2019 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 104
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.msec.2019.109962
  • Dergi Adı: MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Anahtar Kelimeler: Poly(ethylene oxide), Plasma polymers, Dielectric spectroscopy, Dead layer, Glass transition, PEO-LIKE COATINGS, ULTRATHIN FILMS, ELECTRICAL-CONDUCTIVITY, STRUCTURAL RELAXATION, AC CONDUCTIVITY, DEPENDENCE, SPECTROSCOPY, TEMPERATURE, CONSTANT, BEHAVIOR
  • İstanbul Üniversitesi Adresli: Evet

Özet

Plasma poly(ethylene oxide) thin films at different thicknesses of 20, 100, 250, 500 nm were deposited by plasma-assisted physical vapor deposition on glass substrates between aluminum electrodes in capacitor form at 5 W plasma discharge power. The structural analyses were performed by Fourier transform in7frared spectroscopy. The dielectric properties such as dielectric constant kappa' and electric modulus M '' were defined by dielectric spectroscopy measurements. Dielectric spectroscopy measurements were performed in the angular frequency range of 10(-1)-10(6) rad/s and temperature range of 353-173 K range. The measurement results showed that alpha, beta, and gamma-relaxations, which are the expected relaxations in polymeric structures, are effective on total polarization in the investigated frequency and temperature range. Dielectric constant exhibits an increase till 500 nm, then reaches a saturation behavior. When resonance angular frequencies belonging to alpha-relaxation were fitted by Vogel-Fulcher-Tamman equation. It was observed that glass transition temperatures increase with decreasing thickness. These results support the influence of the dead layer to total polarization and the dynamics of the structure. Besides, it was shown that dielectric spectroscopy is a useful way to analyze the glass transition temperature in thin film form.