Polyaramides, such as Kevlar, are of great technological importance for their extraordinary mechanical performance. As fibers, they are used in personal safety, for reinforcement of tires and ropes, and in further material composites that require extreme mechanical stability. However, the properties of the polymer depend on the environmental conditions. Specifically, elevated temperatures and/or irradiation with UV light seriously affect its toughness. Classical approaches to protect polyaramide fibers from these external factors rely on coatings with resins or metal oxides, which typically increase the weight and reduce the flexibility of the polymer. Here, we present a bioinspired approach to stabilize the mechanical properties of the polyaramide. With our solvent free vapor phase approach, zinc oxide is infiltrated into the polymer structure, resulting in intermolecular cross-linking of the polymer chains. The procedure results in an increased degradation temperature of the polyaramide, while at the same time it protects the fibers against UV-induced degradation. The chemical interaction between the zinc oxide and the polymer is theoretically modeled, and a chemical structure of the resulting organic−inorganic hybrid material is proposed.

Graphene is an attractive material for its physicochemical properties, but for many applications only chemically synthesized forms such as graphene oxide (GO) and reduced graphene oxide (rGO) can be produced in sufficient amounts. If considered as electrode material, the intrinsic defects of GO or rGO may have negative influence on the conductivity and electrochemical properties. Such defects are commonly oxidized sites that offer the possibility to be functionalized with other materials in order to improve performance. In this work, we demonstrate how such ultimately efficient functionalization can be achieved: namely, through controlled binding of very small amount of materials such as RuO2 to rGO by atomic layer deposition (ALD), in this way substituting the native defect sites with RuO2 defects. For the example of a supercapacitor, we show that defect functionalization results in significantly enhanced specific capacitance of the electrode and that its energy density can be stabilized even at high consumption rates.

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