Enhancing hydrophilicity and comprehensive antifouling properties of microfiltration membrane by novel hyperbranched poly(N-acryoyl morpholine) coating for oil-in-water emulsion separation

Cationic Copolymer with Amphiphilic Side Chain and Hydrophobic Siloxane/Polycaprolactone Main Chain for Marine Antifouling Coating

Cationic copolymers formulated with different weight percentages of random copolymerized amphiphilic poly(carboxybetaine methacrylate ester)-poly(methyl methacrylate)-polyvinylpyrrolidone (PCBMAE-PMMA-PVP) side chain and polycaprolactone (PCL)/siloxane main chain were developed via a one-pot continuous reaction for the preparation of marine antifouling coatings. By tuning the weight percentage of the side chain and main chain, a 30% quaternization degree can be achieved without obvious gelation of the cationic copolymer. The hydrolyzable PCBMAE in the side chain and degradable PCL in the main chain led to the self-replenishment of the coating. Moreover, the surface hydrophilicity of the developed coatings was greatly improved owing to the creation of a zwitterionic group during PCBMAE hydrolysis. Results on the weight loss rate of the coating revealed that the amphiphilic side chains, more specifically, the PCBMAE moiety rather than PCL moiety in the hydrophobic main chain, dominated the surface renewal speed. Therefore, the fouling-resistance and fouling-release abilities of the developed cationic copolymer-based coatings were largely promoted compared with the control samples, which only had a main chain. Additionally, experimental results demonstrated that a higher content of amphiphilic side chains correlated with less protein adsorption, but a higher content of siloxane showed more advantages in antibacterial ability. The antibacterial rate of the developed coatings against Escherichia coli and Staphylococcus aureus ranged from 83 to 95%. The marine field test manifested that the optimized coatings can stand the marine biofouling for four months in the thriving growth season of marine microorganisms.

Microstructure, Physical and Biological Properties, and BSA Binding Investigation of Electrospun Nanofibers Made of Poly(AA-co-ACMO) Copolymer and Polyurethane

In this study, poly(AA-co-ACMO) and polyurethane-based nanofibers were prepared in a ratio of 1:1 (NF11) and 2:1 (NF21) as antimicrobial carriers for chronic wound management. Different techniques were used to characterize the nanofibers, and poly(AA-co-ACMO) was mostly found on the surface of PU. With an increase in poly(AA-co-ACMO) dose from 0 (PU) and 1:1 (NF11) to 2:1 (NF21) in the casting solution, the contact angle (CA) was reduced from 137 and 95 to 24, respectively, and hydrophilicity was significantly increased. As most medications inhibit biological processes by binding to a specific protein, in vitro protein binding was investigated mechanistically using a stopped-flow technique. Both NF11 and NF21 bind to BSA via two reversible steps: a fast second-order binding followed by a slow first-order one. The overall parameters for NF11 (K_a = 1.1 × 10⁴ M^-1, K_d = 89.0 × 10^-6, ΔG⁰ = -23.1 kJ mol^-1) and NF21 (K_a = 189.0 × 10⁴ M^-1, K_d = 5.3 × 10^-6 M, ΔG⁰ = -27.5 kJ mol^-1) were determined and showed that the affinity for BSA is approximately (NF11)/(NF21) = 1/180. This indicates that NF21 has much higher BSA affinity than NF11, although BSA interacts with NF11 much faster. NF21 with higher hydrophilicity showed effective antibacterial properties compared to NF11, in agreement with kinetic data. The study provided an approach to manage chronic wounds and treating protein-containing wastewater.