A facile post-modification strategy for carboxylic acid-functionalized UV-responsive pressure-sensitive adhesives

UV-responsive pressure-sensitive adhesives (PSAs) were achieved through the ring-opening reactions of N-carbonyl aziridine radicals.

Point of care testing using rapid automated antigen testing for SARS-COV-2 in care homes – an exploratory safety, usability and diagnostic agreement evaluation

Introduction Successful adoption of POCTs (Point-of-Care tests) for COVID-19 in care homes requires the identification of ideal use cases and a full understanding of the contextual and usability factors that affect test results and minimise biosafety risks. This paper presents a scoping-usability and test performance study of a microfluidic immunofluorescence assay for COVID-19 in care homes. Methods A mixed-methods evaluation was conducted in four UK care homes to scope usability and to assess the agreement with qRT-PCR. A dry run with luminescent dye was conducted to explore biosafety issues. Results The agreement analysis was conducted on 227 asymptomatic participants (159 staff and 68 residents) and 14 symptomatic participants (5 staff and 9 residents). Asymptomatic specimens showed 50% (95% CI:1.3%−98.7%) positive agreement and 96% (95% CI: 92.5%−98.1%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.911 (95% CI: 0.857−0.965). Symptomatic specimens showed 83.3% (95% CI: 35.9%−99.6%) positive agreement and 100% (95% CI: 63.1%−100%) negative agreement with overall prevalence and bias-adjusted Kappa (PABAK) of 0.857 (95% CI: 0.549−1). The dry run highlighted four main sources of contamination that led to the modification of the standard operating procedures. Simulation post-modification showed no further evidence of contamination. Conclusion Careful consideration of biosafety issues and contextual factors associated with care home are mandatory for safe use the POCT. Whilst POCT may have some utility for ruling out COVID-19, further diagnostic accuracy evaluations are needed to promote effective adoption.

Facilitated propylene transport in mixed matrix membranes containing ZIF-8@Agmim core-shell hybrid material

The ZIF-8@Agmim core-shell hybrid material was synthesized via a favorable post-modification method of ion exchange (PMIE). This infrequent ZIF-8@Agmim core-shell structure maintains a well- integrated pore size that is almost the same as ZIF-8. The similar equilibrium isotherms with ZIF-8 and better kinetic separation towards propylene/propane than ZIF-8 render ZIF-8@Agmim to be an interesting candidate for propylene/propane separation. The core-shell hybrid nanomaterial was further used as nanofillers in the polymer of intrinsic microporosity matrix (PIM-1) for propylene/propane separation. The resultant MMMs exhibited a simultaneous increase in C3H6 permeability and C3H6/C3H8 ideal selectivity compared to pure polymer membrane owing to a synergistic effect of molecular sieving from ZIF-8 and π-complexation of Ag+ with propylene. The separation performance of the prepared MMM surpasses the upper bound line of polymer membranes. Furthermore, the hybrid materials possess superb photochemical stability and the corresponding MMMs exhibit excellent anti-aging property and long-term stability.

“Exhaustive” Baeyer-Villiger Oxidation of Poly(Methyl Vinyl Ketone) and Its Copolymers

The development of “exhaustive” (nearly quantitative) post-modification reactions relies heavily on the efficiency of their corresponding small-molecule protocols. However, the direct translation of existing small-molecule protocols into post-polymerization modifications were often troublesome due to undesired side reactions. For example, the development of an “exhaustive” BaeyerVilliger (BV) post-modification using existing small-molecule BV protocols suffered from a lack of reactivity or significant chain scission. Herein, we demonstrate that a careful re-optimization of a small-molecule transformation on a polymer substrate allowed us to overcome such challenges, thereby enabling an “exhaustive” BV post-polymerization modification. Furthermore, a one-pot copolymerization/“exhaustive” BV post-modification procedure was developed to produce copolymers of vinyl acetate (VAc) and more activated monomers (MAMs) in a convenient and scalable manner. This user-friendly methodology provides a general access to synthetically challenging poly(VAc-co-MAM)s including both statistical and narrow-dispersed block copolymers and could greatly facilitate the exploration of applications with such materials.