Zwitter‐wettable acrylic polymeric coating on glasses for anti‐fog applications

Anti‐fog coatings have received significant attention because of their versatile applications to reduce light scattering during high humid conditions. Primarily, hydrophilic/superhydrophilic coatings are applied upon the transparent substrate to improve visibility at high humidity. The high solubility of the hydrophilic/superhydrophilic coatings in water is the main drawback for their long‐term operational durability. We will report for the first time the development of functional copolymers which produces water insoluble hydrophilic coating upon application on glass surfaces. Such surfaces are commonly known as “Zwitter‐Wettable” surfaces that have been developed from entirely polymeric substances using methacrylic and acrylic monomers. A series of random copolymers were synthesized using free radical polymerization of the common and commercially available monomers which were subsequently characterized using various analytical techniques, such as, GPC, 1 H‐NMR, and FTIR. These newly designed copolymers contained both the hydrophobic parts made up of methyl and 2‐ethylhexyl groups, which provide good stability under high humid conditions and hydroxyl and carboxylic acid groups which will provide the required hydrophilicity or water absorption capacity. These polymeric coatings on the glass surfaces exhibit water advancing contact angles in the range of 57 ± 3° to 78 ± 3° with excellent anti‐fog property. The anti‐fog property of the polymeric films could be tuned easily by changing the ratio of hydrophobic and hydrophilic monomers.