Optical sequencing of single synthetic polymers

Revealing the heterogeneous catalytic kinetics of PtRu nanocatalysts at the single particle level

Comparison of the structural features and catalytic performance of bimetallic nanocatalysts will help to develop a unified understanding of structure-reaction relationships. The single-molecule fluorescence technique was utilized to reveal the differences in catalytic kinetics among PtRu bimetallic nanocatalysts and Pt and Ru monometallic nanocatalysts at the single particle level. The results show that bimetallic nanocatalysts have higher apparent rate constants and desorption rate constants relative to monometallic nanocatalysts, which leads to their higher catalytic activity. At the single particle level, bimetallic nanocatalysts have a wider distribution of apparent rate constants, suggesting that bimetallic nanocatalysts have higher activity heterogeneity relative to monometallic nanocatalysts. By investigating the relationship between the reaction rate and the rate of dynamic activity fluctuations, it was found that spontaneous surface restructuring and reaction-induced surface restructuring of nanoparticles occurred. The surface of bimetallic nanoparticles restructured faster, which made the bimetallic nanocatalysts more active. These findings provide new insights into the design of highly active bimetallic nanocatalysts.

Precision synthesis of diblock copolymers via free radical photopolymerization

Diblock copolymers of phenyl methacrylate (PMA) and butyl methacrylate (BMA) were synthesized using dual-wavelength photopolymerization with a bifunctional photoinitiator 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl(E)-3-(1-methyl-1H-pyrrol-2-yl)acrylate (PAA-2959).

Electrochemical recycling of polymeric materials

Polymeric materials play a pivotal role in our modern world, offering a diverse range of applications. However, they have been designed with end-properties in mind over recyclability, leading to a crisis in their waste management. The recent emergence of electrochemical recycling methodologies for polymeric materials provides new perspectives on closing their life cycle, and to a larger extent, the plastic loop by transforming plastic waste into monomers, building blocks, or new polymers. In this context, we summarize electrochemical strategies developed for the recovery of building blocks, the functionalization of polymer chains as well as paired electrolysis and discuss how they can make an impact on plastic recycling, especially compared to traditional thermochemical approaches. Additionally, we explore potential directions that could revolutionize research in electrochemical plastic recycling, addressing associated challenges.

Achieving high molecular weight alternating copolymers of 1-octene with methyl acrylate via Lewis acid catalyzed copolymerization

The radical (co)polymerization of long-chain α-olefins (C4+) to produce high molecular weight (Mw) polymers is of great importance. However, this process is currently faced with significant challenges due to the presence of less reactive allylic radicals during radical (co)polymerization, leading to oligomers or polymers with extremely low Mw (less than 1 × 104 g mol-1). Using copolymerization of 1-octene with methyl acrylate (MA) as a proof-of-concept for addressing this challenge, we present a feasible method for synthesizing high Mw α-olefin copolymers via scandium trifluoromethanesulfonate (Sc(OTf)3)-mediated radical copolymerization. In this case, copolymers of 1-octene and MA (poly(1-octene-alt-MA)) with a Mw exceeding 3 × 104 g mol-1 were successfully synthesized in the presence of Sc(OTf)3. Meanwhile, the presence of alternating 1-octene-MA sequential structures was observed. To further enhance the Mw of poly(1-octene-alt-MA), a difunctional comonomer, 1,7-octadiene, was introduced to copolymerize with 1-octene and MA. The results indicate that the incorporation of difunctional comonomer leads to a significant increase in the Mw of the copolymers synthesized. The addition of 1 mol% of 1,7-octadiene resulted in a copolymer with a remarkably high Mw of up to 13.45 × 104 g mol-1 while still maintaining a high degree of the alternating 1-octene-MA sequence (41%). The influence of polymerization parameters on the molecular weight were also investigated. Increasing the monomer concentration, reducing the dosage of initiator, and lowering the polymerization temperature have been found to be advantageous in enhancing the molecular weight. This approach has also been successfully applied to the synthesis of high molecular weight alternating copolymers of other long-chain α-olefins, including 1-hexene, 1-decene and 1-tetradecane, with methyl acrylate. In summary, this study provides a feasible method for converting "less activated" α-olefins into high Mw olefin copolymers. This approach holds significant potential for the production of value-added polyolefins, thus offering promising prospects for future applications.