Effects of Tetraethylene Glycol Chains and Amine Hydrochloride Salts on the Antifogging Performance of Amino-Functionalized Polysilsesquioxanes

This study investigated the effects of incorporating tetraethylene glycol chains and amine hydrochloride salts into amino-functionalized polysilsesquioxane (PSQ) films for antifogging applications. To this end, poly(3-aminopropyl-co-tetraethylene glycol)silsesquioxane (PSQ-AP1/TEG1) and poly(3-(2-aminoethyl)aminopropyl-co-tetraethylene glycol)silsesquioxane (PSQ-AEAP1/TEG1) were synthesized via the sol–gel method. Subsequently, poly(3-(2-aminoethyl)aminopropyl-co-tetraethylene glycol)silsesquioxane hydrochloride (PSQ-AEAP1/TEG1-Cl) films were prepared by immersing PSQ-AEAP1/TEG1 films in a hydrogen chloride methanolic solution. The incorporation of tetraethylene glycol chains reduces water uptake (WU) while maintaining high transparency in PSQ-AP1/TEG1 and PSQ-AEAP1/TEG1 films, inhibiting fog formation. In particular, PSQ-AEAP1/TEG1-Cl films exhibit excellent antifogging properties, retaining transparency when exposed to water vapor at 40 °C from a distance of 2 cm. The transmittance of PSQ-AP1/TEG1, PSQ-AEAP1/TEG1, and PSQ-AEAP1/TEG1-Cl films exceeded 90% at 400 nm. Additionally, PSQ-AEAP1/TEG1-Cl films demonstrate exceptional stability in terms of WU when the films were repeatedly exposed to 25 and 95% relative humidity. Thus, incorporating tetraethylene glycol chains and amine hydrochloride salts into amino-functionalized PSQs improves transparency, surface morphology, and reduction in WU changes against humidity fluctuations. These findings highlight the potential of ammonium- and tetraethylene glycol-modified PSQ films as high-performance antifogging materials with superior hydrophilicity, transparency, and reduction in WU against humidity fluctuations.