Controlled surface wettability by plasma polymer surface modification

Inspired by nature, tunable wettability has attracted a lot of attention in both academia and industry. Various methods of polymer surface tailoring have been studied to control the changes in wetting behavior. Polymers with a precisely controlled wetting behavior in a specific environment are blessed with a wealth of opportunities and potential applications exploitable in biomaterial engineering. Controlled wetting behavior can be obtained by combining surface chemistry and morphology. Plasma assisted polymer surface modification technique has played a significant part to control surface chemistry and morphology, thus improving the surface wetting properties of polymers in many applications. This review focuses on plasma polymerization and investigations regarding surface chemistry, surface wettability and coating kinetics, as well as coating stability. We begin with a brief overview of plasma polymerization; this includes growth mechanisms of plasma polymerization and influence of plasma parameters. Next, surface wettability and theoretical background structures and chemistry of superhydrophobic and superhydrophilic surfaces are discussed. In this review, a summary is made of recent work on tunable wettability by tailoring surface chemistry with physical appearance (i.e. substrate texture). The formation of smart polymer coatings, which adjust their surface wettability according to outside environment, including, pH, light, electric field and temperature, is also discussed. Finally, the applications of tunable wettability and pH responsiveness of polymer coatings in real life are addressed. This review should be of interest to plasma surface science communality particularly focused controlled wettability of smart polymer surfaces.