Hydrophobic plasma polymerized hexamethyldisilazane thin films: characterization and uses

Abstract

Hexametildisilazane (HMDS) plasma polymerized thin films obtained using low frequency power supplies can be used to make adsorbent films and turn surfaces hydrophobic. The aim of this work was to verify the hydrophobicity and adsorption properties of HMDS thin films (with and without the addition of oxygen, resulting in double or single layer films) obtained using an inductive reactor powered with a 13.56 MHz power supply. Single and double layer thin films were deposited on silicon for film characterization, polypropylene (PP) for ultraviolet (UVA/UVC) resistance tests, piezoelectric quartz crystal for adsorption tests. The double layer (intermixing) of HMDS plasma polymerized films and HMDS plasma oxidized surfaces showed a non-continuous layer. The films showed good adhesion to all substrates. Infrared analysis showed the presence of CHn, SiCH3, SiNSi and SiCH2Si within the films. Contact angle measurements with water showed hydrophobic surfaces. UVA/UVC exposure of the films resulted in the presence of cross-linking on carbonic radicals and SiCH2Si formation, which resulted in a possible protection of PP against UVA/UVC for a duration of up to two weeks. Adsorption tests showed that all organic reactants were adsorbed but not water. Plasma etching (PE) using O2 showed that even after 15 minutes of exposure the films do not change their hydrophobic characteristic but were oxidized. The results point out that HMDS films can be used: for ultraviolet protection of flexible organic substrates, such as PP, for sensor and/or preconcentrator development, due to their adsorption properties, and in spatial applications due to resistance for O2 attack in hostile conditions, such as plasma etching

Artificial Superhydrophobic and Antifungal Surface on Goose Down by Cold Plasma Treatment

“…On the other hand, a significant reduction in contact angles and an increase in tilt angles, when there is a complete lack of surface globular morphology, as in the case of layers deposited on silicon wafers, indicates a very Table 2 also includes the results for the layers deposited on silicon wafers, which in turn exhibit a lower hydrophobicity than the native down and down pellets. The CA values measured for these samples showed good agreement with the literature reports for such materials obtained under similar conditions [33][34][35][36].…”

“…In turn, the presence of polar N-H groups in the pp-HMDSN layers, as indicated by the weak band at 1176 cm −1 , should act towards hydrophilicity. According to the well-established view [34,36,48], the organic fraction in the form of methyl groups derived from precursor molecules, which are retained in the deposited layers, is essential for the hydrophobic properties of these layers. As shown in Figure 5, the content of methyl groups in both materials is similar.…”

MEMS-based shear characterization of soft hydrated samples

“…During each experiment both chambers were enclosed in aluminum foil to block ambient light. A similar HDMS treatment was been reported to last for four months [28]. …”

Effect of surface modification on the properties of plasma‐polymerized hexamethyldisiloxane thin films

“…Organosilicon thin films, obtained by plasma polymerization in plasma-enhanced chemical vapor deposition (PECVD) systems from precursors containing silicon, are well-known for their wide range of modern technological applications, such as corrosion protective coatings, [1][2][3][4][5] humidity and gas sensing, [6][7][8] hydrophobic layers, 9,10 hard coatings, 11,12 and optical/electrical interlayers. [13][14][15] Hexamethyldisiloxane (HMDSO) is among the frequently used precursors because of its nontoxicity and its relatively low cost.…”