4. Conclusions
A designing and screening strategy for novel bio-inspired zwitterionic polymer for rapid underwater adhesion and long-term antifouling stability was proposed. The polymer molecules are divided into three parts to fulfill the different functions of the antifouling material and connect the different modules. In the process of the design of zwitterionic polymer, different head groups, tail chains, scaffolds, and degrees of branching are considered and compared. The adsorption capacity, fouling resistance, adsorption configuration, and surface properties of molecules on the hydroxylation silicon wafer are compared through multi-scale molecular simulation. By continuously screening different molecules of each module, Dopa, TREN, and PSBMA are the optimal molecules for the head group, scaffold, and tail chain in this system, respectively. All the calculation results are consistent and prove that tri-Dopa-PSBMA may become a target molecule with excellent properties.
In addition, tri-Dopa-PSBMA and sin-Dopa-PSBMA were successfully synthesized by an ATRP method to be used to compare the surface adsorption properties. From XPS characterization, surface adsorption kinetics of Dopa-PSBMA was monitored to show that tri-DOPA-PSBMA adheres to the substrate much faster than sin-Dopa-PSBMA in aqueous solutions. The facile dip-coating method under an ambient environment has important practical significance. At the same time, the LSCM image of FITC-BSA adhered substrates indicated that tri-Dopa-PSBMA has excellent anti-protein adsorption ability and long-term stability on the silica surface at 4 ºC and 37 ºC. More importantly, the adhesion time of the tri-Dopa-PSBMA to the target substrate underwater by the solution dip-coating method is less than ten minutes, and there are no relevant reports of surface modification of the polymer within ten minutes. Finally, tri-Dopa-PSBMA is applied to modify the commonly used hydrophobic PVDF membrane. The tri-Dopa-PSBMA can be efficiently grafted on the PVDF membrane surface to fabricate surfaces with good surface antifouling and self-cleaning ability.
In summary, all calculations and experimental characterizations corroborate each other, indicating a successful combination of theory and experiment for the rational design of antifouling material. The mode of theoretical design and screen, experimental synthesis, and practical application greatly enhance new functional materials’ design efficiency. Our general molecular engineering strategy offers a rapid way to design and synthesize functional polymers for specific environments.