A novel facile synthesis of metal nitride@metal oxide (BN/Gd2O3) nanocomposite and their antibacterial and anticancer activities

In this study, a novel core/shell nanocomposite structure (h-BN@Gd2O3 NCs) was created for the first time by combining hexagonal boron nitride (h-BN) with doped gadolinium oxide (Gd2O3) using different laser pulse numbers, i.e., 150, 338, and 772 pulses. We employed various analytical techniques, including mapping analysis, FE-SEM, EDS, HRTEM, SAED, XRD, zeta potential analysis, DLS, FTIR, Raman spectroscopy, and PL measurements, to characterize the synthesized h-BN, c-Gd2O3, and h-BN@Gd2O3 NCs (338 pulses). XRD results indicated hexagonal and cubic crystal structures for BN and Gd2O3, respectively, while EDS confirmed their chemical composition and elemental mapping. Chemical bonds between B-N-Gd, B-N-O, and Gd-O bands at 412, 455, 474, and 520 cm-1 were identified by FTIR analysis. The antimicrobial and anticancer activities of these NCs using agar well diffusion and MTT assays. They exhibited potent antibacterial properties against both Gram-positive and Gram-negative pathogens. Furthermore, NCs have reduced the proliferation of cancerous cells, i.e., human colon adenocarcinoma cells (HT-29) and human breast cancer cells (MCF-7), while not affecting the proliferation of the normal breast cell line (MCF-10). The anticancer efficacy of NCs was validated by the AO/EtBr assay, which confirmed apoptotic cell death. Blood compatibility on human erythrocytes was also confirmed by hemolytic and in vitro toxicity assessments. The compiled results of the study proposed these nanoparticles could be used as a promising drug delivery system and potentially in healthcare applications.

Environmental treatment and remediation using h-BN based smart and hybrid membrane

Corrosion is a major problem resulting from acid gases found in natural gas being transported in pipelines. To solve this problem, high aspect ratio h-BN nanosheets have been incorporated and are properly assimilated in the CA matrix, this led to an increase in tortuous path of flow for the gas resulting in smooth, dense membrane samples causing exceptional permeability reduction. Hexagonal Boron Nitride (h-BN) nanosheets have been synthesized and incorporated into cellulose acetate (CA) matrix using solution casting method. Nanosheets of various sizes, separated by varying centrifugation speeds (i.e. 500 rpm, 700 rpm, 1500 rpm, 2000 rpm and 2500 rpm), have been prepared and used for our work. The resulting nanocomposites, having thickness ranging between 40 and 60 μm, were then tested for CO₂ gas permeability reduction using both short-term (8 h) tests as well as long-term (72-h tests). As a result of these tests, a maximum CO₂ permeability reduction of 99.84% is found with a minimum CO₂ permeability of 3.25 barrer. For dimensional analysis of both nanosheets and nanocomposites, scanning electron microscopy (SEM) analysis is used. For verifying the presence of the required functional groups in our synthesized samples, FT-IR spectroscopy is used. Moreover, to confirm the presence of crystalline phases, X-ray Diffraction (XRD) analysis is used. Also, tensile testing is used to analyze the mechanical robustness and it was found that nanocomposite samples exhibited higher tensile strength as compared to pristine samples. Furthermore, tribological property analysis was also carried out for adhesion testing of polymeric material with steel.

Bias-Enhanced Formation of Metastable and Multiphase Boron Nitride Coating in Microwave Plasma Chemical Vapor Deposition

Boron nitride (BN) is primarily a synthetically produced advanced ceramic material. It is isoelectronic to carbon and, like carbon, can exist as several polymorphic modifications. Microwave plasma chemical vapor deposition (MPCVD) of metastable wurtzite boron nitride is reported for the first time and found to be facilitated by the application of direct current (DC) bias to the substrate. The applied negative DC bias was found to yield a higher content of sp³ bonded BN in both cubic and metastable wurtzite structural forms. This is confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Nano-indentation measurements reveal an average coating hardness of 25 GPa with some measurements as high as 31 GPa, consistent with a substantial fraction of sp³ bonding mixed with the hexagonal sp² bonded BN phase.

Enhancing tribo-mechanical properties and thermal stability of nylon 6 by hexagonal boron nitride fillers

Mechanical and tribological properties of nylon 6 and nylon 6/h-BN composites were investigated in this paper. Tensile, hardness, and impact tests were carried out for mechanical properties, while wear tests on pin-on-disc were carried out for tribological properties identification. Abrasion resistance tests were carried out on the TABER apparatus to analyze the abrasive wear of materials. SEM, XRD, and TGA were used to characterize the materials and to understand the distinctive features of nylon 6 and nylon 6/h-BN composites. Experimental results show that the mechanical properties and tribological behavior of nylon 6 got enhanced by the h-BN fillers. Tensile strength and modulus of elasticity were enhanced by 15.2% and 64.5%, respectively, while hardness and impact strength were enhanced by 3.45% and 6%, respectively. COF and wear rate of composites decreased up to 4 wt% filler reinforcement due to smooth transfer film formation. Coefficient of friction (COF) and wear resistance were improved by 10–15% and 8–10%, respectively, at various testing conditions. h-BN reinforcement in the matrix resulted in more weight loss due to abrasion and it reduced the abrasion resistance of nylon 6 by 5.5 times. Thermal stability was slightly increased, and crystallinity was little affected by the h-BN fillers.