Bismuth Quantum Dot (Bi QD)/Polydimethylsiloxane (PDMS) Nanocomposites with Self-Cleaning and Antibacterial Activity for Dental Applications

Construction of Reinforced Self-Cleaning and Efficient Photothermal PDMS@GDY@Cu Sponges toward Anticorrosion and Antibacterial Applications

Copper (Cu)-based materials are widely used in many fields from industry to life, including marine, medical apparatus and instruments, and microelectronic devices owing to their superior thermal, electrical, and mechanical properties. However, the interaction of copper with aggressive and fouling liquids under normal circumstances easily brings about severe bacterial accumulation, resulting in undesirable functionality degeneration and bacterial infections. In this contribution, we reported a novel copper-based sponge, polydimethylsiloxane (PDMS)@graphdiyne (GDY)@Cu, constructed by in situ synthesis of GDY on a commercial Cu sponge, followed by the modification of PDMS. The as-fabricated PDMS@GDY@Cu sponge not only possesses excellent self-cleaning activity against the pollution of daily drinks and dirt due to an improved static contact angle (~136°), but also display a remarkably enhanced anticorrosion performance, attributed to intimate coverage of chemically stable GDY and PDMS on the Cu sponge. Based on high photothermal effect of GDY, the PDMS@GDY@Cu sponge also displays significantly improved antibacterial activities under irradiation. In addition, due to excellent chemical stability of PDMS and GDY, self-cleaning behavior and photothermal-assisted antibacterial performance are well maintained after long-term attack of bacteria. These results demonstrate that GDY-based functional coatings hold great promises in the protection of copper devices under harsh conditions.

PDMS/TiO2 and PDMS/SiO2 Nanocomposites: Mechanical Properties' Evaluation for Improved Insulating Coatings

The use of nanoparticles (NPs) as reinforcements in polymeric coatings allows for direct interaction with the polymeric chains of the matrix, resulting in a synergistic process through physical (electrostatic forces) and chemical interactions (bond formation) for the improvement of the mechanical properties with relatively low weight concentrations of the NPs. In this investigation, different nanocomposite polymers were synthesized from the crosslinking reaction of the hydroxy-terminated polydimethylsiloxane elastomer. Different concentrations (0, 2, 4, 8, and 10 wt%) of TiO₂ and SiO₂ nanoparticles synthesized by the sol-gel method were added as reinforcing structures. The crystalline and morphological properties of the nanoparticles were determined through X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The molecular structure of coatings was through infrared spectroscopy (IR). The crosslinking, efficiency, hydrophobicity, and adhesion degree of the study groups were evaluated with gravimetric crosslinking tests, contact angle, and adhesion tests. It was observed that the crosslinking efficiency and surface adhesion properties of the different nanocomposites obtained were maintained. A slight increase in the contact angle was observed for the nanocomposites with 8 wt% compared to the polymer without reinforcements. The mechanical tests of indentation hardness and tensile strength following the ASTM E-384 and ISO 527 standards, respectively, were performed. As the nanoparticle concentration increased, a maximum increase of 157% in Vickers hardness, 71.4% in elastic modulus, and 80% in tensile strength was observed. However, the maximum elongation remained between 60 and 75%, ensuring that the composites did not become brittle.

Emerging Xene-Related Nanostructures for Versatile Applications

Investigations into semiconductor nanomaterials from both an academic and industrial point of view are of great significance [...].