Photomediated-reversible-deactivation radical polymerisation (photo-RDRP) has a limited scope of available photocatalysts (PCs) due to multiple stringent requirements for PC properties, limiting options for performing efficient polymerisations under long wavelengths. Here we report an oxygen-mediated reductive quenching pathway (O-RQP) for photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerisation. The highly efficient polymerisations that are performed in the presence of ambient air enable an expanded scope of available PCs covering a much-broadened absorption spectrum, where the oxygen tolerance of PET-RAFT allows high-quality polymerisation by preventing the existence of O2 in large amounts and efficient O-RQP is permitted due to its requirement for only catalytic amounts of O2. Initially, four different porphyrin dyes are investigated for their ability to catalyse PET-RAFT polymerisation via an oxidative quenching pathway (OQP), reductive quenching pathway (RQP) and O-RQP. Thermodynamic studies with the aid of (time-dependent) density functional theory calculations in combination with experimental studies, enable the identification of the thermodynamic constraints within the OQP, RQP and O-RQP frameworks. This knowledge enables the identification of four phthalocyanine photocatalysts, that were previously thought to be inert for PET-RAFT, to be successfully used for photopolymerisations via O-RQP. Well-controlled polymerisations displaying excellent livingness are performed at wavelengths in the red to near-infrared regions. The existence of this third pathway O-RQP provides an attractive pathway to further expand the scope of photocatalysts compatible with the PET-RAFT process and facile access to photopolymerisations under long wavelengths.

A novel antimicrobial copolymer containing sulfitobetaine is studied and has excellent application potential in EOR.

A water-soluble poly(AM-AA-DMDAAC-TCAP) was prepared using acrylamide (AM), acrylic acid (AA), diallyl dimethyl ammonium chloride (DMDAAC), and N-allyl-4-methylbenzenesulfonamide (TCAP), and the synthesis conditions were investigated. The obtained copolymer was characterized by FTIR, 1 H-NMR, SEM, TG, and XRD. The temperature resistance and thickening function of the copolymer are improved significantly compared with that of partially hydrolyzed polyacrylamide. It is found that the viscosity of copolymer could achieve up to 53.3% retention rate at 120 C compared to that at 30 C. About 16.6% for enhanced oil recovery is obtained by poly(AM-AA-DMDAAC-TCAP) brine solution at 65 C. In addition, the results of XRD show that 3000 mg/L copolymer combined with 10 wt % KCl solution could reduce the d-spacing of sodium montmorillonite from 18.94 to 14.86 Å exhibiting remarkable effect on inhibiting hydration of clays. All the results demonstrate that poly(AM-AA-DMDAAC-TCAP) have excellent performance for potential application in enhance oil recovery.