Metal nanoparticles (NPs) have been extensively studied as heterogeneous catalysts for chemical reactions of small molecules. However, using these NPs to catalyze multi-component reactions into complex molecular structures, for example, polymers, has been rarely reported. We demonstrate a size-dependent catalysis of AuPd alloy NPs for synthesizing highly pure rigid organic polymer polybenzoxazole (PBO) with controlled polymerization in a one-pot reaction condition. The PBO shows the enhanced thermal, chemical, and mechanical stability under challenging environmental conditions.

Graphene-based materials are being developed for a variety of wearable technologies to provide advanced functions that include sensing; temperature regulation; chemical, mechanical, or radiative protection; or energy storage. We hypothesized that graphene films may also offer an additional unanticipated function: mosquito bite protection for light, fiber-based fabrics. Here, we investigate the fundamental interactions between graphene-based films and the globally important mosquito species,Aedes aegypti, through a combination of live mosquito experiments, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena. The results show that graphene or graphene oxide nanosheet films in the dry state are highly effective at suppressing mosquito biting behavior on live human skin. Surprisingly, behavioral assays indicate that the primary mechanism is not mechanical puncture resistance, but rather interference with host chemosensing. This interference is proposed to be a molecular barrier effect that preventsAedesfrom detecting skin-associated molecular attractants trapped beneath the graphene films and thus prevents the initiation of biting behavior. The molecular barrier effect can be circumvented by placing water or human sweat as molecular attractants on the top (external) film surface. In this scenario, pristine graphene films continue to protect through puncture resistance—a mechanical barrier effect—while graphene oxide films absorb the water and convert to mechanically soft hydrogels that become nonprotective.

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