Poly (Dimethylsiloxane) Coating for Repellency of Polar and Non-Polar Liquids

Abstract

The wettability of poly (dimethylsiloxane) (PDMS) coating on plasma-treated glass was studied at room temperature using polar and non-polar liquids. The wettability was investigated regarding the liquids’ surface tensions (STs), dielectric constants (DCs) and solubility parameters (SPs). For polar liquids, the contact angle (CA) and contact angle hysteresis (CAH) are controlled by the DCs and non-polar liquids by the liquids’ STs. Solubility parameter difference between the PDMS and the liquids demonstrated that non-polar liquids possessed lower CAH. An empirical model that integrates the interfacial properties of liquid/PDMS has been composed. Accordingly, the difference between the SPs of PDMS and the liquid is the decisive factor affecting CAH, followed by the differences in DCs and STs. Moreover, the interaction between the DCs and the SPs is of importance to minimize CAH. It has been concluded that CAH, and not CA, is the decisive attribute for liquid repellency of PDMS coating.

Modulating the surface and mechanical properties of textile by oil-in-water emulsion design

“…We would, however, like to highlight that the viscosity of PDMS plays a critical role in such physical deposition process as the surface energy of all three PDMS used in the present work is the same. Another important difference to the previous work [60][61][62][63] where permanent coating was developed on textiles such as cotton fabrics, PDMS layer studied in the present work is not chemically bond to the textile due to the safety regulatory requirements, and hence could be removed in the subsequent washing cycles, although there might be some build-up over the course of a §multiple washingdeposition cycle.…”

“…In recent studies, [60][61][62][63] robust coating based on PDMS or other compounds was developed on textiles to render a superhydrophobic or superamphiphobic characteristics, which was evaluated by using water contact angle (WCA). These studies highlight the importance of controlling surface wettability of textile, which underpins the applications such as oil-water separation and anti-fouling.…”

Molecularly Capped Omniphobic Polydimethylsiloxane Brushes with Ultra‐Fast Contact Line Dynamics

“…However, there has been no consensus as to what constitutes a sufficiently low CAH, though values have generally fallen below 10°. [13][14][15][16] PDMS brushes are one type of omniphobic surface, and CAH values of various liquids on PDMS brushes have ranged from 0°for alkanes, [17,18] to as high as 16°with water. [19] The low CAH of PDMS brushes arises from their liquid-like nature, [19] as the brush-like morphology combined with the low glass transition temperature of PDMS keeps the surface mobile, minimizing contact line pinning.…”

“…However, there has been no consensus as to what constitutes a sufficiently low CAH, though values have generally fallen below 10°. [ 13–16 ]…”