Superhydrophilic Polymer Brushes with High Durability and Anti-fogging Activity

Abstract

Hydrophilic surface coatings have made it into commercial application as possible solutions for problems such as fogging, frosting, and biofouling. However, there is an inherent contradiction: superhydrophilic coatings can prevent these unwanted phenomena, but they are also readily dissolved by water. To address this longevity concern, the present work introduces a fully aqueous surface-initiated (SI) polymerization under ambient conditions for the facile formation of durable superhydrophilic polymer coatings. The aqueous SI photoinduced electron transfer reversible addition−fragmentation chain transfer polymerization (SI-PET-RAFT) approach developed herein uses water as a sole solvent and can be performed in an ambient air atmosphere. This circumvents traditional shortcomings in SI radical polymerization related to limited hydrophilic monomer solubility in organic solvents and oxygen tolerance. In addition, polymerization under mild yellow light eliminates possible substrate degradation that can occur with conventional thermal or UV-light treatment. The cationic, anionic, and zwitterionic polymer films engineered in this study show promise as functional materials with enhanced durability, demonstrated to effectively combat the challenge of surface fogging. The described approach is user-friendly, cost-and time-efficient, and scalable and produces efficient anti-fogging coatings that outperform commercial solutions in both optical quality and durability.

Polycarbonate Surface Modification via Aqueous SI-PET-RAFT

“…From this CDTPA-functionalized PC surface, surface-initiated RAFT polymerization can be initiated and mediated following established procedures. 14 Variations in temperature and time for surface attachment of diamino species were explored to identify conditions that provide surface functionalization without disrupting the optical properties of the PC. The surface attachment conditions that showed limited disruption to the optical clarity of the PC were found to be 10 min at 50 °C, using 1 vol % ethylenediamine in ethanol.…”

“…12 One challenge with this approach, however, is longevity: since these coatings are not covalently tethered to the PC substrate, delamination is likely upon exposure to solvents, and they are more susceptible to wear by friction. 14 The covalent attachment of amino groups can be leveraged as an alternative to produce durable, hydrophilic polymer brush coatings on PC. Amino groups have been shown to react with PC via urethane linkages.…”

“…SI-PET-RAFT is a versatile polymerization system that has recently been employed to address a broad range of applications from photolithography 21 to organic LEDs 22 to anti-biofouling. 23,24 The more recently developed aqueous SI-PET-RAFT 14 is an ideal approach to versatile PC surface modification specifically due to its mild aqueous conditions and use of visible light, avoiding organic solvents as well as UV and thermal initiation sources that could otherwise damage the PC substrate. 25…”

A Simple and Robust Method to Prepare Polyelectrolyte Brushes on Polymer Surfaces

“…Grafting polyelectrolytes by surface-initiated polymerization usually leads to a high coating density and controllable layer thickness, but is often performed in organic solvents, with only a few examples working under aqueous conditions. [27][28][29][30][31] Grafting-to approaches can be applied in water for amphiphilic polymers, but due to steric and electrostatic repulsion of the charged polymers, it is difficult to achieve a grafting density high enough to show sufficient activity for the respective application. [32] In this study, we aim to develop a simple and robust method to produce polyelectrolyte brush coatings with polyglycerol sulfate that can be applied to nonactivated polymer material surfaces via a dip-coating method.…”

Efficient Antiscaling Technology Based on Superhydrophobicity Coupled Ultrasonic Technology

“…The superhydrophobic surface has the characteristics of slowing down the rate of scaling, which provides a way to realize the above goal. , Superhydrophobic surfaces refer to materials with a water contact angle (WCA) higher than 150° and a roll angle (RA) less than 10°, which have been widely studied by scholars. Studies have shown that the superhydrophobic materials have the properties of anti-icing, , anticorrosion, antifogging, , and oil–water separation. , Therefore, it is possible to develop an efficient antiscaling technology by combining superhydrophobicity and ultrasonication.…”