Front Cover: A versatile platform is developed for creating functional π-conjugated organic nanoparticles stabilized by amphiphilic block copolymers for green H2 photocatalytic generation. The donor–acceptor–donor trimers nanoparticles show enhanced photocatalytic activity (≈0.6 mmol g−1 h−1) for H2 production via water splitting. More details can be found in article 2400395 by Thiago R. Guimarães, Jean-Louis Bobet, Eric Cloutet, and co-workers.
Amino acid-based poly(ester urea)s are an attractive class of polymers that are of interest for a variety of biomedical applications. Generally, amino acid-based poly(ester urea)s are prepared by polymerization of diamines, which are obtained from the corresponding amino acids and aliphatic diols. This article presents an alternative synthetic strategy that uses diamine monomers obtained from aromatic, 4-hydroxycinnamic acid-derived diols. A library of structurally related diamine monomers has been prepared by coupling l-leucine to 4-hydroxycinnamic acid-based diols that incorporate alkyl spacers of different lengths. The exploration of 4-hydroxycinnamic acid as a building block is interesting as it can be obtained from various biological resources, such as for example lignin, and thus provides an opportunity to take advantage of (under-utilized) bio-based renewables for the design of new polymer materials. These diamine monomers can be copolymerized in a solvent-free, one-pot, two-step process using dimethyl carbonate as an environmentally sustainable reagent to afford amino acid-based aromatic poly(ester urea) homo- and copolymers with thermal properties that can be tuned by varying the chemical structure of the diamine monomer, or via copolymerization of two different monomers.
Förster resonance energy transfer (FRET) is an established tool for measuring distances between two molecules (donor and acceptor) on the nanometer scale. In the field of polymer science, the use of FRET to measure polymer end-to-end distances (Ree) often requires complex synthetic steps to label the chain ends with the FRET pair. This work reports an anthracene-functionalized chain-transfer agent for reversible addition-fragmentation chain-transfer (RAFT) polymerization, enabling the synthesized chains to be directly end-labeled with a donor and acceptor without the need for any post-polymerization functionalization. Noteworthily, this FRET method allows for chain conformation measurements of low molecular weight oligomers in situ, without any work-up steps. Using FRET to directly measure the average Ree of the oligomer chains during polymerization, the chain growth of methyl methacrylate, styrene, and methyl acrylate is investigated as a function of reaction time, including determining their degree of polymerization (DP). It is found that DP results from FRET are consistent with other established measurement methods, such as nuclear magnetic resonance (NMR) spectroscopy. Altogether, this work presents a broadly applicable and straightforward method to in situ characterize Ree of low molecular weight oligomers and their DP during reaction.
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