Catheters are widely used and play an important role in medicine. However, catheter-associated infection is prevalent even under stringent sterile conditions. Biofilms are formed when bacteria populate the surfaces of catheters. This makes the biofilm resistant to antibiotics. Hence, it is imperative for there to be an inherently antifouling and anti-bacterial catheter to mitigate the formation of biofilm. This paper aims to outline the synthesis of non-leachable anti-biofilm and anti-bacterial cationic film coatings through direct polymerization using supplemental activator and reducing agent surface initiated atom transfer radical polymerization (SARA SI-ATRP). Three crosslinked cationic coatings comprising of Diallyl dimethyl ammonium chloride (DADMAC), or ε-poly-L-lysine HCl methacrylic acid (EPL-MA) together with a crosslinker (polyethylene glycol dimethacrylate, PEGDMA) were investigated. These non-leachable covalently linked coatings with DADMAC can achieve more than 2 log reduction (99.0%) with Methicillin-resistant Staphylococcus aureus (MRSA) and 1.25 log reduction (94.4%) with Vancomycin resistant Enterococcus (VRE) in in vitro studies.
The boron carbide (B4C) nanoparticles doping mesophase pitch (MP) was synthesized by the in-situ doping method with tetrahydrofuran solvent, and the corresponding MP−based carbon fibers (CFs) were successfully prepared through the melt−spinning, stabilization, carbonization and graphitization processes. The structural evolution and properties of boron−containing pitches and fibers in different processes were investigated for exploring the effect of B4C on mechanical, electrical and thermal properties of CFs. The results showed that the B4C was evenly dispersed in pitch fibers to provide active sites of oxygen, resulting in a homogeneous stabilization and ameliorating the split−ting microstructures of CFs. Moreover, the thermal conductivity of B1−MP−CF prepared with 1 wt.% B4C increased to 1051 W/m•K, which was much higher than that of B0−MP−CF prepared without B4C (659 W/m•K). While the tensile strength of B4C−doped CFs was lower than that of pristine CFs. In addition, a linear relationship equation between the graphite microcrystallite parameter (ID/IG) calculated from Raman spectra and the thermal conductivity (λ) calculated according to the electrical resistivity was found, which was beneficial to understand the thermal properties of CFs. Therefore, the doping B4C nanoparticles in MP did play a significant role in reducing the graphitization temperatures due to the boron catalytic graphitization but decreasing the mechanical properties due to the introduction of impurities.