Improved water barrier properties of polylactic acid films with an amorphous hydrogenated carbon (a-C:H) coating
| Autor: | Tom Lindfors, Christian B. Fischer, Alberto Catena, Stefan Wehner, Lajos Höfler, Zhanna A. Boeva |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Diffusion Analytical chemistry chemistry.chemical_element 02 engineering and technology General Chemistry Chemical vapor deposition 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Amorphous solid Absorbance chemistry.chemical_compound Polylactic acid chemistry Attenuated total reflection General Materials Science 0210 nano-technology Layer (electronics) Carbon |
| Zdroj: | Carbon. 120:157-164 |
| ISSN: | 0008-6223 |
| DOI: | 10.1016/j.carbon.2017.05.005 |
| Popis: | 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 cm 2 s −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. |
| Databáze: | OpenAIRE |
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