Zwitterionic polymer brush coatings with excellent anti-fog and anti-frost properties

Abstract

The formation of fog and frost on transparent surfaces can lead to many problems in our daily life. To address these problems, polymer brushes based on two zwitterionic analogues, poly(sulfobetaine methacrylate) (pSBMA) and poly(sulfobetaine vinylimidazole) (pSBVI), have been prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). Hydrophilic and superhydrophilic pSBMA and pSBVI polymer brushes were prepared by controlling the thickness of the coatings to study the effect of wettability on the anti-fog and anti-frost properties. X-ray photoelectron spectroscopy (XPS), ellipsometry and atomic force microscopy (AFM) were respectively used to determine the interfacial elemental composition, the thickness and the morphology of the brushes. The wettability of the polymer brushes was measured using a water contact angle goniometer. Their anti-fog and anti-frost capabilities were determined visually and tested quantitatively by UV-vis spectroscopy. The results indicated that the optical transmittance of substrates modified with superhydrophilic polymer coatings under both hot and cold fogging conditions was very high. Additionally, no visible frost was formed on the superhydrophilic substrates after storage in a freezer at -20 o C for the duration of the experiment. These results convincingly demonstrated that the resistance of the modified substrates to fogging and frosting is strongly correlated to the surface wettability. Moreover, there is no considerable difference in the performance of pSBMA and pSBVI polymer brushes, but the former is preferred because SBMA monomer is commercially available and requires short polymerization time to obtain superhydrophilicity.

Water drop-surface interactions as the basis for the design of anti-fogging surfaces: Theory, practice, and applications trends

“…Different research groups have recently developed fog-resistant films containing sulfonic and phosphonic groups, well known for their high water-absorbing characteristics and underwater oleophobicity [125][126][127][128]. Ezzat and colleagues [129] fabricated anti-fogging glasses with extreme wettability (WCA < 5°) by anchoring zwitterionic poly(sulfobetaine methacrylate) (pSBMA) and poly(sulfobetaine vinylimidazole) (pSBVI) polymer brushes, while Huang et al [130] deposited by dip-coating silanized zwitterionic sulfobetaine silane (SBSi) on glasses (Fig. 10a).…”

Understanding the role of hollow sub-surface structures in reducing ice adhesion strength

“…Reducing ice adhesion is an important strategy to mitigate ice accretion on exposed surfaces, such as power lines, wind turbines, aircraft and offshore platforms. [1][2][3] Various approaches towards lowering ice adhesion have been introduced, including superhydrophobic surfaces, [4][5][6][7] aqueous lubricating layers, 8-10 organic lubricating layers, [11][12][13][14] polyelectrolyte brush layers, [15][16][17] organogels, [18][19][20][21] and multiscale crack initiators promoted icephobic surfaces. [22][23][24][25] Of these approaches, the macro-scale crack initiators promoted surfaces represent a promising alternative with great potential in further reducing ice adhesion strength for a given surface chemistry and texture.…”

Mussel‐inspired catechol‐based chemistry for direct construction of super‐hydrophilic and waterproof coatings on intrinsic hydrophobic surfaces

“…The external approaches are powerful, but there are still lack of cost‐effective and straightforward fabrication strategies. Current techniques often require plasma, corona, chemical, or even flame and thermal steps . All of these treatments are expensive and energy intensive.…”

“…Current techniques often require plasma, corona, chemical, or even flame and thermal steps. 13,14 All of these treatments are expensive and energy intensive. Thus, a green synthesis without any treatment would be more convenient and is highly desired.…”