Improved water barrier properties of polylactic acid films with an amorphous hydrogenated carbon (a-C:H) coating

Zhanna Boeva, Alberto Catena, Lajos Höfler, Stefan Wehner, Christian B. Fischer, Tom Lindfors

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

9 Citeringar (Scopus)

Sammanfattning

For the first time a 120 nm thick layer of amorphous hydrogenated carbon (a-C:H) deposited on top of 50 μm thick polylactic acid (PLA) films with radio-frequency plasma-enhanced chemical vapor deposition has been used as barrier to impede water diffusion through free-standing PLA films. Surface structures were examined by AFM and the water uptake was measured with Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy, a powerful technique for studying the diffusion of water through polymeric membranes. We have compared the water uptake of uncoated and a-C:H coated PLA films by placing the initially dry films in contact with deionized water for 24 h and monitoring the time-dependent absorbance changes in the FTIR spectra of the OH stretching bands of water in the wavenumber region of 2960–3750 cm−1. Mathematical modeling revealed that the water uptake was best described with a model consisting of three diffusion coefficients ascribed to monomeric and dimeric, clustered and bulk water having values between 1.1 × 10−8 and 2.6 × 10−10 cm2s−1. We show that the thin a-C:H layer effectively decreased the water uptake of PLA with 55% after a contact time of 24 h and even more at shorter times.
OriginalspråkOdefinierat/okänt
Sidor (från-till)157–164
TidskriftCarbon
Volym120
DOI
StatusPublicerad - 2017
MoE-publikationstypA1 Tidskriftsartikel-refererad

Nyckelord

  • Water uptake
  • Poly(lactic acid)
  • Water transport
  • ATR-FTIR spectroscopy
  • Diffusion

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