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In this study, three-dimensional (3D) polyvinyl alcohol (PVA)/aligned boron nitride (BN) aerogel framework nanocomposites with high performance were fabricated by a facile strategy. The boron nitride powder was initially hydrolyzed and dispersed with a chemically crosslinked plasticizer, diethyl glycol (DEG), in the PVA polymer system. The boron nitride and DEG/PVA suspensions were then mixed well with different stoichiometric ratios to attain BN/PVA nanocomposites. Scanning electron microscopy revealed that BN platelets were well dispersed and successfully aligned/oriented in one direction in the PVA matrix by using a vacuum-assisted filtration technique. The formed BN/PVA aerogel cake composite showed excellent in-plane and out-of-plane thermal conductivities of 0.76 W/mK and 0.61 W/mK with a ratio of BN/PVA of (2:1) in comparison with 0.15 W/mK for the pure PVA matrix. These high thermal conductivities of BN aerogel could be attributed to the unidirectional orientation of boron nitride nanoplatelets with the post-two days vacuum drying of the specimens at elevated temperatures. This aerogel composite is unique of its kind and displayed such high thermal conductivity of the BN/PVA framework without impregnation by any external polymer. Moreover, the composites also presented good wettability results with water and displayed high electrical resistivity of ~1014 Ω cm. These nanocomposites thus, with such exceptional characteristics, have a wide range of potential uses in packaging and electronics for thermal management applications.

The increasing cases of bacterial infections originating from resistant bacteria are a serious problem globally and many approaches have been developed for different purposes to treat bacterial infections. Aerogels are a novel class of smart porous materials composed of three-dimensional networks. Recently, aerogels with the advantages of ultra-low density, high porosity, tunable particle and pore sizes, and biocompatibility have been regarded as promising carriers for the design of delivery systems. Recently, aerogels have also been provided with antibacterial activity through loading of antibacterial agents, incorporation of metal/metal oxides and via surface functionalization and coating with various functional groups. In this mini-review, the synthesis of aerogels from both conventional and low-cost precursors is reported and examples of aerogels displaying antibacterial properties are summarized. As a result, it is clear that the encouraging antibacterial performance of aerogels promotes their use in many antibacterial applications, especially in the food industry, pharmaceutics and medicine.

Tuning the synthesis conditions of polyaniline (PANI) such as aniline monomer’s protonation states and adding surfactants into polymerization mixture or even the existence of bacterial cellulose (BC) had a substantial influence on the final properties. To explore the relationship between components presented in the polymerization mixture, simulation tools (molecular dynamics (MD)/Monte Carlo (MC)/Density functional theory (DFT)) can be used. Herein, nanocomposite aerogels of BC/PANI were fabricated in the presence of anionic surfactants; sodium dodecyl benzene sulfonate (SDBS) or sodium dodecyl sulfonate (SDS) at two different concentrations (0.05 M and 1 M) of HCl solution. Two types of aniline monomers were considered in the polymerization mixture based on HCl solution’s concentrations including neutral and protonated aniline in 0.05 and 1 M, respectively. Various morphologies from nanobelts (with a width of 100–500 nm) and polyhedrons (with a thickness of 100–700 nm) in 0.05 M of acid solution in the presence of SDBS or SDS, respectively, were detected. Based on DFT computations it was found that electrostatic interactions and the formation of hydrogen bonds play a vital role in the interfacial interaction mechanism between both surfactants (SDBS and SDS) and different protonation forms of aniline monomers. Nevertheless, in the case of SDBS and aniline monomers (in both 0.05 and 1 M of HCl solutions), an excess interaction mechanism, namely π-π stacking, was observed, which enhanced the interaction between them and confirmed by experimental results. Therefore, the highest conductivity of 0.8 S/cm was obtained for the BC/PANI prepared with SDBS in 1 M of HCl solution. Besides, the smallest energy gap of 2.74 eV was predicted from DFT calculations for this sample that further confirmed its high electrical properties and smaller band gap at 3 nm, which was also confirmed by MD and MC.