Controlled Surface Wettability by Plasma Polymer Surface Modification

Abstract

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.

Plasma Treatment of Polymer Powder as an Effective Tool to Functionalize Polymers: Case Study Application on an Amphiphilic Polyurethane

“…35% reduction in Number Average Molecular Weight for CHP407_50 samples respect to the virgin CHP407. Additionally, a lower number of carboxylic groups was achieved with increasing gas feed rate, in agreement with what reported by Iqbal et al [22]. The amount of exposed carboxylic groups, measured by Toluidine Blue O colorimetric assay (here adapted to measure carboxylic groups exposed on water soluble materials) was 5.3 × 10 18 ± 5.5 × 10 17 , 2 × 10 18 ± 3 × 10 17 , and 2.4 × 10 18 ± 1.1 × 10 17 -COOH units/g for CHP407_10, CHP407_30, and CHP407_50, respectively.…”

“…Subsequently, the reactor was purged with AA vapor at 10 µL/min for 15 min. In this phase plasma was induced for 10 min at 200 W alternated power supply (9 Hz, Pulse ON 10 ms, Pulse OFF 1000 ms, Duty Cycle 0.01, mean power applied 22 W) to prevent polymer degradation [21,22]. Ar supply was kept constant during the entire process at the same flow selected for the etching phase.…”

Applications of the COST Plasma Jet: More than a Reference Standard

“…The low wettability of polymers can be a problem that needs resolving. The increased hydrophilicity of the polymer surface is achieved by using industrial plasmas, but the chemistry which yields the desired properties of polymers is not well known [30].…”

Review on Blueprint of Designing Anti-Wetting Polymeric Membrane Surfaces for Enhanced Membrane Distillation Performance

“…In the Cassie-Baxter state, air trapped in the grooves between surface features forms a composite (air/solid) hydrophobic surface, leading to a larger contact angle compared to the contact angle θ with a flat surface. In contrast, in the Wenzel state, the liquid on the surface enters the grooves, leading to higher surface wettability, due to the increase in contact area [7,39,40]. Therefore, it can be concluded from the Wenzel equation that surface roughness amplifies the wettability of the original surface.…”