Photochemically Cross-Linked Perfluoropolyether-Based Elastomers: Synthesis, Physical Characterization, and Biofouling Evaluation

A series of reactive liquid perfluoropolyether (PFPE) precursors were synthesized which call be photochemically cross-linked (UV-cured) into high-performance PFPE elastomers in one step. To investigate how fundamental changes in the PFPE molecular structure correlate to bulk and surface properties, the variable functional end group, molecular weight, and the copolymer content were systematically explored in relation to thermal stability, contact angle/surface tension, modulus, and biofouling behavior. The morphologies of these PFPE materials were studied using differential scanning calorimetry, dynamic mechanical thermal analysis, and small-angle X-ray scattering. From these studies, it was determined that clusters of polymerized functional end groups were found to be nanophase separated within the PFPE matrix. By varying the cross-link density. the Young's modulus of the fully cross-linked PFPE clastomeric film could be tuned from 1.5 to 90 MPa with a critical surface tension of 8.6-16 mN/m. The marine antifouling and fouling-release properties of the cross-linked PFPE elastomeric coatings were evaluated by settlement and release assays involving zoospores and sporelings (Young plants), respectively, of green fouling alga Ulva.