Surface Hydration\nand Antifouling Activity of Coatings\nof Polymers and Their Zwitterionic Derivatives Prepared Using Initiated\nChemical Vapor Deposition (iCVD)

Sum frequency generation vibrational\nspectroscopy was applied to\nstudy the surface hydration and protein adsorption behavior on several\npolymer coatings based on pyridine, imidazole, and amine side groups\nalong with vinyl or methacrylate backbones and their corresponding\nzwitterionic forms with carboxybetaine or sulfobetaine side chains,\nprepared by initiated chemical vapor deposition (iCVD). iCVD also\nenables facile tuning of the cross-linking density of the polymer\ncoatings by blending in a cross-linker during the deposition, namely,\n1,3,5,7-tetramethyl-1,3,5,7-tetravinyl cyclotetrasiloxane. Our results\nshow that both the low- and high-cross-linking density zwitterionic\npolymers exhibit significantly better antifouling activities compared\nto those of the polymers without the zwitterionic side chains. The\nweak hydration signals from the low-density zwitterionic polymer/water\ninterfaces were caused by the permeation of the polymer layer by water.\nThe iCVD method is a widely applicable methodology to prepare zwitterionic\npolymer coatings with an excellent antifouling property.