Self-stratified fouling release coatings based on polydimethylsiloxane incorporated with acrylate-MQ silicone copolymer

In this study, an acrylate-MQ silicone copolymer (A-MQ) was synthesized and characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and differential scanning calorimetry. Next, fouling release coatings based on polydimethylsiloxane (PDMS) were prepared by incorporating A-MQ. Self-stratified coatings were prepared by controlling the additive amount of A-MQ. Surface property analysis results showed that the appropriate A-MQ additive amount ensured surface smoothness and hydrophobicity in the prepared coatings (P/A-MQ18). Incorporating A-MQ enhanced the mechanical properties of the coatings. Moreover, the shore hardness values of the surface and interface were different, indicating stratification. Observing the fracture microstructures further confirmed the formation of self-stratified structures owing to the enrichment of the surface layer by PDMS during the curing process. More importantly, a high additive amount of A-MQ led to further phase separation with the appearance of "sea–island structures" in the prepared coatings, and this deteriorated the mechanical properties of the coatings (P/A-MQ20). The pull-off test results indicated that the self-stratified coating broke from the upper layer enriched with PDMS, indicating high adhesion strength. The biofilm adhesion assay confirmed the excellent antifouling performance of the self-stratified coating, which also resulted from the enrichment of the upper layer by PDMS. These findings can be extremely useful for developing high-performance fouling release coatings.