Improving the wettability and antiprotein adsorption property of PDMS by swelling–deswelling approach

In order to improve the wettability and antiprotein adsorption property of PDMS, heptamethyltrisiloxane (a well-known superspreader) was coated onto the PDMS substrates by a swelling–deswelling process. PDMS films were first immersed in heptamethyltrisiloxane solution mixtures to coat heptamethyltrisiloxane onto PDMS. During the deswelling process, the hydrophobic siloxane group of the superspreader heptamethyltrisiloxane was trapped in the PDMS matrix, while the hydrophilic group EO was exposed to the surface. In this manner, heptamethyltrisiloxane was finally coated on the PDMS surface via swelling–deswelling process. Contact angle measurements, optical property analyses, X-ray photoelectron spectroscopy, and atomic force microscopy were used to confirm that durable hydrophilic and transparent PDMS surfaces were successfully obtained. The PDMS surface wettability could be adjusted by tuning the solubility parameters of the solution mixture. Additionally, antiprotein adsorption property was investigated and the result indicated the heptamethyltrisiloxane was tethered onto the PDMS surface. The swelling–deswelling method can be applied for the modification of other crosslinked polymers to obtain antifouling surfaces and functional materials for biomedical applications.

A superspreading surfactant (Silwet-L77) was coated onto the PDMS surface by the swelling–deswelling process, to improve its hydrophilicity and antiprotein adsorption properties.