RESUMEN
We report a next-generation, biocide-free, and durable marine antifouling coating technology. To achieve this, we combined two different polymers previously developed by us. First, we synthesized well-defined 2-hydroxypropyl acrylamide (HPA) based bottlebrush polymers with concentrated polymer brush (CPB) structures, which exhibit excellent bioinertness, and second, we synthesized photoreactive copolymers of 2-hydroxypropyl acrylamide (HPA) and N-benzophenone acrylamide (BPA), which can be cross-linked by exposure to sunlight for 30 min. Simply mixing the bottlebrush polymers with the photoreactive copolymers and applying these as a coating provided a scalable method for achieving effective antifouling properties in one step on a broad range of polymer substrate materials. The resistance of bottlebrushes against acid and base hydrolysis was demonstrated in accelerated degradation experiments at 80 °C, and the coating thickness was found to be stable after 3 months of incubation in sea water. Optimized coatings prevented cypris larva attachment for up to 9 days and prevented the settling of marine organisms in the sea for up to 73 days. Due to the ease of application, long-term durability, and effective antifouling performance, our bottlebrush coating technology is expected to be exploited in biocide-free marine paints.
RESUMEN
Poly(acrylic acid) (PAA) is modified by 5-(4-ß-alanylaminophenyl)-10,15,20-tris(4-sulfonatophenyl) porphinatoiron(III) to yield iron porphyrin-bearing PAAs (FeP(n)s) through a condensation reaction. FeP(n)s were further functionalized by Py3CD, which is a per-O-methylated ß-cyclodextrin (CD) dimer with a pyridine linker and includes the porphyrin pendants to form ferric hemoCD-P(n)s. Ferrous hemoCD-P(3), having three porphyrin chromophores in a polymer chain, is shown to bind molecular oxygen (P(1/2)=7.9±1.4 Torr) in aqueous solution at pH 7.0 and 25 °C, affording oxy-hemoCD-P(3). Oxy-hemoCD-P(3) is biphasically autoxidized to ferric hemoCD-P(3), with 27% of the dioxygen adducts being rapidly oxidized. The rate of autoxidation of oxy-hemoCD-P(15), having 15 porphyrin chromophores in a polymer chain, was much faster than that of oxy-hemoCD-P(3), thus suggesting self-catalyzed autoxidation of oxy-hemoCD-P(n)s. Oxy-hemoCD-P(n)s are markedly stabilized by catalase, thereby indicating that hydrogen peroxide generated from oxy-hemoCD-P(n) accelerates the autoxidation. Most of the hemoCD-P(3) molecules injected into the femoral vein of a rat remained in the body, though about 16% of the hemoCD-P(3) molecules were excreted in the urine as a carbon monoxide adduct.
