Study on the Core-Shell Reversion of PSBMA- b-PLMA Nanoparticles for the Fabrication of Antifouling Coatings

In this paper, two series of poly(sulfobetaine methacrylate)- b-poly(lauryl methacrylate) (PSBMA- b-PLMA) diblock copolymers were prepared to investigate the core-shell reversion of amphiphilic copolymers. Experimental results proved that the PSBMA- b-PLMA copolymers can be self-assembled as core-shell nanoparticles in chloroform. Moreover, ¹H NMR spectra and contact angle measurements revealed that there is a transitional PSBMA/PLMA block ratio of 0.6, above which the nanoparticles are capable of switching their core and shell in aqueous solution. Consequently, nanoparticles with PSBMA/PLMA block ratios above 0.6 showed superior antifouling and antibacterial abilities to those with block ratios below 0.4. Moreover, it was also found that the block chain length plays an important role in core-shell reversion as evidenced by ¹H NMR spectra, water contact angle, and antifouling tests. As a result, coatings fabricated with the PLMA₁₀₀ series of nanoparticles showed better antifouling abilities than those of the PLMA₁₅₀ series at the same block ratio probably because of the thinner shell of PLMA₁₀₀ copolymers. PSBMA₁₀₀- b-PLMA₁₀₀ was proved to be the best candidate for the fabrication of antifouling coatings as it exhibited the highest efficacy in antibacterial adhesion and antiprotein adsorption. This study provided a facile method to fabricate antifouling coatings by developing amphiphilic diblock copolymers with tuned hydrophobic/hydrophilic block ratio, block chain length, etc.