Superhydrophobicity on transparent fluorinated ethylene propylene films with nano-protrusion morphology by Ar + O2 plasma etching: Study of the degradation in hydrophobicity after exposure to the environment

Fluorinated ethylene propylene (FEP) films were made superhydrophobic by Ar + O2 plasma etching process. Field emission scanning electron microscopy and atomic force microscopy studies of the plasma-treated FEP samples detected the presence of uniformly distributed nano-protrusions exhibiting a low surface roughness necessary for maintaining the transparency of the samples. In fact, optical transmittance measurements showed an improvement in the transparency of FEP samples after plasma treatment. The X-ray photoelectron spectroscopic analysis showed the presence of –CF x –O–CF x – (x = 1, 2, or 3) linkages in both untreated and plasma-treated samples which explains the hydrophilic nature (contact angle below 90∘) of the untreated sample. Fourier transform infrared spectroscopy showed no changes in the bulk properties of the plasma-treated samples. Moreover, exposure to the environment caused the surfaces to lose their superhydrophobic property in an indefinite amount of time. This has been further studied through a water immersion experiment and explained through the wetting state transition from Cassie state to Wenzel state.

[1]  E. Durand,et al.  Surface modification of several carbon-based materials: comparison between CF4 rf plasma and direct F2-gas fluorination routes , 2004 .

[2]  H. Barshilia,et al.  Nanometric multiscale rough Zn–ZnO superhydrophobic thin films: Self-diffusion of zinc and effect of UV irradiation , 2010 .

[3]  Xi Zhang,et al.  Superhydrophobic surfaces: from structural control to functional application , 2008 .

[4]  Harish C. Barshilia,et al.  Superhydrophobic polytetrafluoroethylene surfaces with leaf-like micro-protrusions through Ar + O2 plasma etching process , 2014 .

[5]  M. Farzaneh,et al.  Anti-icing performance of superhydrophobic surfaces , 2011 .

[6]  H. Busscher,et al.  PREPARATION AND CHARACTERIZATION OF SUPERHYDROPHOBIC FEP-TEFLON SURFACES , 1992 .

[7]  H. Barshilia,et al.  Deposition of TiAlN coatings using reactive bipolar-pulsed direct current unbalanced magnetron sputtering , 2008 .

[8]  B. Lyons.  Radiation crosslinking of fluoropolymers—a review , 1995 .

[9]  M. Farzaneh,et al.  Applications of Plasma Technology in Development of Superhydrophobic Surfaces , 2013, Plasma Chemistry and Plasma Processing.

[10]  A. Cassie,et al.  Wettability of porous surfaces , 1944 .

[11]  T. Satoh,et al.  Morphological change of self-organized protrusions of fluoropolymer surface by ion beam irradiation , 2013 .

[12]  T. Terai,et al.  Fabrication of fine micro protrusions on fluoropolymer surface using ion beam irradiation , 2011 .

[13]  Jin Zhai,et al.  Super-hydrophobic surfaces: From natural to artificial , 2002 .

[14]  Shu Yang,et al.  Self-assembly of nanostructures towards transparent, superhydrophobic surfaces , 2013 .

[15]  Lei Zhai,et al.  Stable Superhydrophobic Coatings from Polyelectrolyte Multilayers , 2004 .

[16]  H. Barshilia,et al.  Effect of substrate roughness on the apparent surface free energy of sputter deposited superhydrophobic polytetrafluoroethylene thin films , 2009 .

[17]  J. Forsythe,et al.  The radiation chemistry of fluoropolymers , 2000 .

[18]  Yiping Zhao,et al.  Nanocarpet effect induced superhydrophobicity. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[19]  U. Schrade,et al.  Long term environmental durability of a superhydrophobic silicone nanofilament coating , 2007 .

[20]  H. Barshilia,et al.  Effect of substrate roughness on the apparent surface free energy of sputter deposited superhydrophobic polytetrafluoroethylene coatings: A comparison of experimental data with different theoretical models , 2010 .

[21]  B. Parekh,et al.  Surface modification of poly(tetrafluoroethylene-co-hexafluoropropylene) with vacuum UV radiation from rotating helium dc arc plasmas , 2007 .

[22]  Michael Newton,et al.  Progess in superhydrophobic surface development. , 2008, Soft matter.

[23]  S. Kulinich,et al.  Superhydrophobic surfaces: are they really ice-repellent? , 2011, Langmuir : the ACS journal of surfaces and colloids.

[24]  Harish C. Barshilia,et al.  Nanometric Multiscale Rough CuO/Cu(OH)2 Superhydrophobic Surfaces Prepared by a Facile One-Step Solution-Immersion Process: Transition to Superhydrophilicity with Oxygen Plasma Treatment , 2011 .

[25]  H. Barshilia,et al.  Wettability of ZnO: A comparison of reactively sputtered; thermally oxidized and vacuum annealed coatings , 2011 .

[26]  R. N. Wenzel.  RESISTANCE OF SOLID SURFACES TO WETTING BY WATER , 1936 .

[27]  P Aebischer,et al.  Selective neuronal cell attachment to a covalently patterned monoamine on fluorinated ethylene propylene films. , 1993, Journal of biomedical materials research.

[28]  T. Young.  III. An essay on the cohesion of fluids , 1805, Philosophical Transactions of the Royal Society of London.

[29]  P. Aebischer,et al.  Neuronal cell attachment to fluorinated ethylene propylene films with covalently immobilized laminin oligopeptides YIGSR and IKVAV. II. , 1995, Journal of biomedical materials research.

[30]  T. Karabacak,et al.  Hydrophobic metallic nanorods with Teflon nanopatches , 2009, Nanotechnology.

[31]  S. Seeger,et al.  Long term studies on the chemical stability of a superhydrophobic silicone nanofilament coating , 2007 .

[32]  T. Terai,et al.  The mechanism of protrusion formation on PTFE surface by ion-beam irradiation , 2009 .

[33]  H. Barshilia,et al.  Nanometric multi-scale rough, transparent and anti-reflective ZnO superhydrophobic coatings on high temperature solar absorber surfaces , 2012 .

[34]  H. Barshilia,et al.  Superhydrophobic nanostructured Kapton® surfaces fabricated through Ar + O2 plasma treatment: Effects of different environments on wetting behaviour , 2013 .

[35]  Teri H. Gregory,et al.  Environmental Exposure Conditions for Teflon® Fluorinated Ethylene Propylene on the Hubble Space Telescope , 2000 .

[36]  R. Passariello,et al.  Management of malignant biliary obstruction: Technical and clinical results using an expanded polytetrafluoroethylene fluorinated ethylene propylene (ePTFE/FEP)-covered metallic stent after 6-year experience , 2008, European Radiology.

[37]  A. Entenberg,et al.  Adhesion of copper to poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) surfaces modified by vacuum UV photo-oxidation downstream from Ar microwave plasma , 2004 .

[38]  P. Kohl,et al.  Plasma chemistry in fluorocarbon film deposition from pentafluoroethane/argon mixtures , 1999 .

[39]  L. Boinovich,et al.  A wetting experiment as a tool to study the physicochemical processes accompanying the contact of hydrophobic and superhydrophobic materials with aqueous media. , 2012, Advances in colloid and interface science.