Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

0497613 - ÚPT 2019 RIV NL eng J - Journal Article
Rashid, Z. - Atay, I. - Soydan, S. - Yagci, Y. - Jonáš, Alexandr - Yilgor, E. - Kiraz, A. - Yilgor, I.
Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment.
Applied Surface Science. Roč. 441, MAY (2018), s. 841-852. ISSN 0169-4332. E-ISSN 1873-5584
Institutional support: RVO:68081731
Keywords : reversible wetting * plasma oxidation * superhydrophobic * superhydrophilic
OECD category: Coating and films
Impact factor: 5.155, year: 2018

Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.
Permanent Link: http://hdl.handle.net/11104/0290169