Tunable Wetting of Polymer Surfaces

Abstract

A simple method was developed for the preparation of polymeric materials with controlled surface wettability or tunable surface wetting. The method is applicable to a large number of polymers, thermoplastic or thermoset. With this method, it is possible to prepare polymer surfaces with static water contact angles ranging from 0° (superhydrophilic) to greater than 170° (superhydrophobic). The method developed is based on spin-coating of a hydrophilic/hydrophobic silica mixture dispersed in an organic solvent or solvent mixture onto the polymer surface. Depending on the hydrophilic/hydrophobic silica ratio in the coating mixture, it is possible to obtain polymer surfaces displaying gradually changing wettability from superhydrophilic to superhydrophobic. In this article, preparation and surface characteristics of polystyrene (PS) and cross-linked epoxy resin (ER) films are provided as general examples. Polymer surfaces obtained were characterized by scanning electron microscopy, white light interferometry, atomic force microscopy, X-ray photoelectron spectroscopy, and static water contact angle measurements. Effects of the type of polymeric substrate and composition of the silica mixture on the surface behavior of the composite systems were investigated.

Influence of the coating method on the formation of superhydrophobic silicone–urea surfaces modified with fumed silica nanoparticles

“…The first method was layer-by-layer spin coating of silica particles onto TPSC surface from a dispersion in THF, which was explained in detail previously [39,40]. TPSC was dissolved in IPA (15% by weight), whereas the hydrophobic silica was dispersed in THF at a concentration of 0.5% by weight and was subjected to ultrasound sonication at a frequency of 35 kHz on a Sonorex RK 255H type bath for 10 h. Dynamic light scattering (DLS) measurements on hydrophobic silica suspensions in THF (10 mg/mL) indicated fairly homogeneous distribution of the silica nanoparticles, with a number average size distribution of 44 ± 9 nm.…”

“…Surface modification of TPSC through layer-by-layer spin coating by using a silica dispersion in THF has already been discussed in detail in our previous publications [39,40,76]. As a result here we will only provide examples regarding the topography, average roughness and water contact angle behavior of the surfaces obtained by this technique as a reference in order to compare them with the topography and properties of the surfaces obtained by other coating techniques.…”

“…These include layer-by-layer deposition [33], electrospinning [34], microphase separation [28,35,36], etching [37,38], spin-coating or dip-coating [28,39,40], sol-gel synthesis [10,41], templating [20,21,28,36,42], spraying [5,43] and many others [10,16,28,37,38,44]. Although a wide range of approaches have been proposed for the preparation of superhydrophobic polymer surfaces, most of them are polymer specific, fairly complex and involve several steps.…”

“…Although a wide range of approaches have been proposed for the preparation of superhydrophobic polymer surfaces, most of them are polymer specific, fairly complex and involve several steps. Recently we reported a fairly simple method, which was based on the spin coating of fumed silica dispersions in an organic solvent onto polymer surfaces for the preparation of polymeric materials with controlled wettability, from superhydrophilic to superhydrophobic [39,40]. The method was applicable to a wide range of polymeric materials, thermoplastic or thermoset.…”

Dual-switchable surfaces between hydrophobic and superhydrophobic fabricated by the combination of click chemistry and RAFT

“…Figure 7 shows AFM and SEM images of the single and aggregations of SiO 2 /P(7-6-AC)-b-PNIPAAm. Compared with the results of TEM, the aggregations of the SiO 2 /P(7-6-AC)-b-PNIPAAm were also observed by AFM and SEM (Figure 7b and 7d) [52]. On Figure 7a, we can find that the SiO 2 /P(7-6-AC)-b-PNIPAAm disperse with each other, but at the irradiation of 365 nm, the SiO 2 /P(7-6-AC)-b-PNIPAAm aggregate together (Figure 7b), which can be due to the photodimerization of the coumarin groups.…”