Synthesis and properties of silicone-modified polyurethane acrylate for magnetically driven blue light photocurable superhydrophobic coatings

A low surface energy silicone-modified polyurethane acrylate (Si-PUA) has been synthesized and employed as the primary constituent for the magnetically driven photocurable coatings. By integrating magnetically driven assembly technology with blue light photocuring technology, a superhydrophobic coating featuring low surface energy and micro/nano rough structures was successfully fabricated. The influences of hydroxy-terminated polydimethylsiloxane (PDMS) content and the R-value (-NCO/-OH) on the performance of PUA and coating systems were investigated using Photo-DSC, TGA, rheology, tensile testing machine, and SEM-EDS. The molecular structure of Si-PUA was characterized using FT-IR and 1HNMR. The result revealed that the composite coating exhibited a minimum surface energy when the PDMS content was 5 wt% and the R-value was 1.6, resulting in a surface free energy of 24 mJ/m2. When the coating formulation consists of a Si-PUA:HEA ratio of 7:3, an initiator dosage of 2% (with CQ/EDB at a 1:1 ratio), and a carbonyl iron powder (CIP) content of 100 wt%, the resulting photocured film exhibits a surface contact angle of 157.6° and a rolling angle of 5°, thereby satisfying the superhydrophobicity standard.