We present a platform strategy that offers diverse flexibility in tailoring the structure and properties of core–shell plasmonic nanoparticles with built-in nanogaps. Our results have demonstrated that polydopamine serves multiple concerted functions as a nanoscale spacer to afford controllable nanogap sizes, a redox-active coating to promote metal shell growth, and a reactive scaffold to exclusively lock molecular probes inside the nanogap for surface-enhanced Raman scattering (SERS). More interestingly, the universal adhesion of polydopamine on diverse colloidal substrates allows for customized synthesis of multishell plasmonic nanogapped nanoparticles (NNPs) and multifunctional hybrid NNPs containing different cores (i.e., magnetic nanoparticles), which are not readily accessible by conventional methods. Internally coupled plasmonic NNPs with broadly tunable spectroscopic properties, highly active SERS, and multifunctionality hold great promise for emerging fields, such as sensing, optoelectronics, and theranostics, as demonstrated by the ultrasensitive SERS detection and efficient photothermal killing of food-borne pathogens here.

We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

Marine biofouling is a problem for marine industry and maritime activities. We have prepared polyurethane with poly(dimethylsiloxane) (PDMS) main chains and N-(2,4,6-trichlorophenyl) maleimide (TCM) pendant groups via a combination of a thiol-ene click reaction and a condensation reaction and studied its properties. The polymer has low surface energy and a high water contact angle. When TCM content in bulk is high enough, sufficient antifoulant groups can be exposed on the surface. Our study reveals that such polymeric surface can effectively inhibit the adhesion and colonization of marine organisms such as bacteria (Micrococcus luteus), diatom Navicula, and barnacle cyprids. Particularly, marine field tests demonstrate that the polymer has excellent antibiofouling performance in 110 days.

Biodegradable polyurethane with N-(2,4,6-trichlorophenyl)­maleimide (TCPM) pendant groups has been prepared via a combination of a thiol–ene click reaction and a condensation reaction. The TCPM moieties acting as antifoulants are released as the polyurethane degrades in the marine environment. The biodegradation and hydrolyzation of the polyurethane were investigated by use of quartz crystal microbalance with dissipation (QCM-D) and hydrolysis experiments. It shows both the enzymatic degradation rate and the hydrolyzation rate decrease with TCPM content, which facilitates increasing the duration of the polyurethane. Marine field tests reveal that the polyurethane has good antifouling ability since the degradation leads to a self-renewal surface and the release of the antifoulants is controlled.

Cationic polymers are one of the main classes of materials investigated against bacteria through the membrane-lysis mechanism. The cationic-hydrophobic balance and distribution of cationic and hydrophobic moieties of these polymers...