RESUMO
Two-dimensional (2D) nanomaterials as molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN), and their hybrid (MoS2/h-BN) were employed as fillers to improve the physical properties of epoxy composites. Nanocomposites were produced in different concentrations and studied in their microstructure, mechanical and thermal properties. The hybrid 2D mixture imparted efficient reinforcement to the epoxy leading to increases of up to 95% in tensile strength, 60% in ultimate strain, and 58% in Young's modulus. Moreover, an enhancement of 203% in thermal conductivity was achieved for the hybrid composite as compared to the pure polymer. The incorporation of MoS2/h-BN mixture nanofillers in epoxy resulted in nanocomposites with multifunctional characteristics for applications that require high mechanical and thermal performance.
RESUMO
Liquid crystal elastomers (LCEs) are unique among shape-responsive materials in that they exhibit large and reversible shape changes and can respond to a variety of stimuli. However, only a handful of studies have explored LCEs for biomedical applications. Here, we demonstrate that LCE nanocomposites (LCE-NCs) exhibit a fast and reversible electromechanical response and can be employed as dynamic substrates for cell culture. A two-step method for preparing conductive LCE-NCs is described, which produces materials that exhibit rapid (response times as fast at 0.6 s), large-amplitude (contraction by up to 30%), and fully reversible shape changes (stable to over 5000 cycles) under externally applied voltages (5-40 V). The electromechanical response of the LCE-NCs is tunable through variation of the electrical potential and LCE-NC composition. We utilize conductive LCE-NCs as responsive substrates to culture neonatal rat ventricular myocytes (NRVM) and find that NRVM remain viable on both stimulated and static LCE-NC substrates. These materials provide a reliable and simple route to materials that exhibit a fast, reversible, and large-amplitude electromechanical response.
RESUMO
Three-dimensional, functional, and porous scaffolds can find applications in a variety of fields. Here we report the synthesis of hierarchical and interconnected porous sponges using a simple freeze-drying technique, employing collagen extracted from animal skin wastes and superparamagnetic iron oxide nanoparticles. The ultralightweight, high-surface-area sponges exhibit excellent mechanical stability and enhanced absorption of organic contaminants such as oils and dye molecules. Additionally, these biocomposite sponges display significant cellular biocompatibility, which opens new prospects in biomedical uses. The approach highlights innovative ways of transforming biowastes into advanced hybrid materials using simple and scalable synthesis techniques.