Synthesis of stretchable antifogging polymer thin film with high affinity for water molecules

Abstract

Recently, as various displays and devices such as wearable and embaddable have been developed, antifogging coating is also required to have high mechanical durability as well as antifogging performance. Herein, a nanoscale stretchable antifogging polymer film equipped with superhydrophilicity was newly designed and synthesized in one-step man-ner using a vapor phase method, initiated chemical vapor deposition (iCVD). The stretcha-ble antifogging polymer film was generated by the copolymerization of 2-hydroxyethyl acrylate (HEA), a soft, hydrophilic monomer, together with a small fraction of a robust crosslinker moiety, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (V3D3), that can stabilize the antifogging surface in aqueous environment. The addition of the V3D3 crosslinker also substantially improved the adhesion of the polymer coating on the substrate materials. The composition of the copolymer film was adjusted precisely by controlling the flow rates of the input monomers in the vapor-phase deposition process. This stretchable polymer film showed outstanding antifogging performance almost 100% transmittance over a long peri-od of time, and it was confirmed the durability that was maintained even through repeated cycle test. Besides, the stretchable antifogging polymer film with the optimized composi-tion showed an elastic limit higher than 300% while maintaining the antifogging perfor-mance. This thin film also has self-cleaning performance derived from superhydrophilicity, and can be deposited anywhere through a vapor phase process, and even deposited on a patterned substrate, showing excellent antifogging performance. We believe the stretchable antifogging polymer film developed in this study is a promising candidate material for var-ious stretchable device applications.