Thermoresponsive Copolymer Microgels via Single-Step Precipitation Polymerization: Random or Block structure?

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ISC researchers. Letizia Tavagnacco, Francesco Brasili and Emanuela Zaccarelli,  working on soft matter coauthored an interesting work on Small

Thermoresponsive Copolymer Microgels Synthesized via Single‐Step Precipitation Polymerization: Random or Block Structure?.” Small (2025): e09795

The internal structure of polymeric colloids is a key property that has attracted increasing attention in soft matter research. The inner morphology of these systems critically influences their phase behavior and functionality, governing their mechanical properties and their physical and chemical interactions. Among the various classes of colloidal systems, thermoresponsive microgels -soft, cross-linked polymer networks that undergo reversible volume transitions in response to temperature changes- are of particular interest. This responsiveness has been widely studied due to its potential exploitation in a broad range of applications, spanning from technological to biomedical fields. Achieving fine control over their internal structure is therefore essential to tailor material responsiveness and expanding the scope of possible applications.

While recent studies have advanced our understanding of the internal structure of homopolymer microgels, such as PNIPAM, comparable investigations of copolymer systems have remained scarce. Through an extensive, multi-technique investigation, which combines scattering experiments and spectroscopy measurements with state-of-the-art simulations of realistic microgels, a group of researchers of CNR ISC and Sapienza, in collaboration with University of Ferrara, University of Florence, University of Rome Tor Vergata, Jülich Centre for Neutron Science (JCNS) and Australian Centre for Neutron Scattering (ACNS), has shown a block-like arrangement of the comonomers within the microgel network. This result is unexpected, given the use of a one-step synthesis copolymerization and challenges the long-standing assumption of a random monomer distribution. These findings, recently published in Small, open new directions for rational microgel design, with a strong impact on applications that depend on finely controlled swelling and phase behavior.

 

This work has been funded by Progetto Co-MGELS granted by the EuropeanUnion – NextGeneration EU under the National Recovery and ResiliencePlan (PNRR) “Fondo PRIN” and by ICSC-Centro Nazionaledi Ricerca in High-Performance Computing, Big Data and QuantumComputing.

 

Authors

Letizia Tavagnacco, Elena Buratti, Jacopo Vialetto, Francesco Brasili, Elisa Ballin, Kuno Schwärzer, Jitendra Mata, Graziano Di Carmine, Monica Bertoldo, Ester Chiessi, Marco Laurati, Emanuela Zaccarelli