Synthesis and Self-assembly of Fluorine-containing Polyurethanes Induced by Polymerization

A series of fluorine-containing polyurethanes (FUs) were polymerized by radical polymerization with 2,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pentyl methacrylate (FDPMA) and double bond capped polyurethane oligomer (DCU) which was synthesized by stepwise polymerization. During the polymerization process, the self-assembly behavior of FU was observed, which is attributed to the conversion of solubility of FDPMA caused by polymerization. The phenomenon in the process of FU polymerization was similar to that of typical emulsion polymerization. The blue-light effect appeared in the primary stage of polymerization, and stable emulsion formed later. The transformation of self-assembled particles during polymerization was evaluated by dynamic light scattering (DLS). It was confirmed by scanning electron microscope (SEM) that the self-assembled particles presented in FU polymerization. Moreover, the self-assembled structure was affected greatly by component contents, and could deform or re-assemble in the process of solvent extraction to various forms, such as sun-flower shape or nanowire. By transmission electron microscope (TEM), it is certified that these self-assembled particles had unambiguous core-shell structure, and could keep boundaries clearly while in mutual extrusion. The stereoscopic morphology of self-assembled structure was characterized by atomic force microscopy (AFM), showing that the ellipsoid shape appeared after the solvent extraction. The surface performance of FU was detected by contact angle tester (CA) and X-ray photoelectron spectroscopy (XPS), it was shown that FU had good hydrophobic and oleophobic performance due to the fluorine enrichment on surface. All the results above indicated that the solubility conversion of FDPMA caused by polymerization is available as an effective means to prepare and control the self-assembled structure of FU, and the product FU has good surface performance and application prospect.