Cleavage, conversion kinetics (say that 10 times fast)

By July 29th, 2019

The RAMP centre assists with both scientific exploration, as well as journal-quality alliteration. The centre was recently acknowledged for our assistance with work published in Macromolecular Rapid Communications by a team of our colleagues here at CSIRO.

The full paper can be accessed here. Please feel free to reach out to us or any of the authors to discuss details of the work.


Copolymerization of Pentafluorophenylmethacrylate with Hydrophilic Methacrylamide Monomers Induces Premature Hydrolytic Cleavage

Active ester polymers are commonly used for fast development of novel polymer libraries, but they require post‐polymerization modification, which is not atom‐efficient or economical. In order to more efficiently produce 2‐hydroxypropyl methacrylamide (HPMAm) libraries, it would be advantageous to perform a direct copolymerization with active ester monomers. In this work, the synthesis of copolymer libraries of pentafluorophenyl methacrylate (PFPMA) and the hydrophilic monomer HPMAm is investigated. Surprisingly, HPMAm induces premature hydrolytic cleavage of PFPMA, which occurs during polymerization and depends on the HPMAm/PFPMA feed ratio. Copolymerization of PFPMA with N‐isopropylmethacrylamide and the methacrylate monomers 2‐hydroxypropylmethacrylate and N‐isopropylmethacrylate reveals that the hydrolytic cleavage is promoted by copolymerization with methacrylamides only. By switching from a thermal‐ to a light‐based initiator and lowering the reaction temperature, premature hydrolytic cleavage of PFPMA is avoided and allows direct copolymerization of HPMAm together with PFPMA to create polymer libraries for biomaterial screening.

figure from published journal

Evolution of the ratios of different PFPMA species over time during polymer synthesis using a HPMAm/PFPMA feed ratio of 80/20. Percentages were calculated by integration of the respective peaks in the 19F‐NMR spectra.

The authors thank Nino Malic for providing advice and the equipment to perform the photo‐initiated RAFT polymerization. The authors gratefully acknowledge Ben Muir and Shaun Howard from the RAMP facility for their help with the kinetics experiments.