Sprecher
Beschreibung
Thermo-responsive microgels are colloidal particles, composed by polymer networks, that undergo a sudden change of volume at the so-called volume phase transition temperature (VPTT). This property is of considerable interest across a wide range of fields, and the ability to tune the VPTT is crucial for many applications. In this talk I will present two examples of investigations of microgels combining numerical simulations and neutron scattering experiments.
In the first part, I will focus on microgels based on the polymer poly(N-isopropylacrylamide) (PNIPAM). I will show that these systems exhibit intriguing features even at temperatures well below the VPTT. By comparing atomistic molecular dynamics simulations with neutron scattering experiments, I will provide evidence that PNIPAM microgels undergo a dynamical transition akin to that observed in proteins [1, 2], in which water plays a driving role [3].
In the second part, I will discuss how simulations spanning different length scales can provide valuable insights into the internal topology and phase behavior of copolymer microgels. I will present a multiscale approach that combines monomer-resolved microgel simulations, based on an in silico synthesis protocol capable of realistically reproducing particle structure [4], with atomistic simulations of polymer chains. By directly comparing numerical form factors with experimental data obtained from small-angle neutron scattering experiments, I will show evidence of preferential domain structure in Poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide), P(NIPAM-co-NIPMAM), copolymer microgels [5].
[1] M. Zanatta, L. Tavagnacco, E. Buratti et al., Science Advances, 4, eaat5895 (2018).
[2] L. Tavagnacco, E. Chiessi, M. Zanatta et al., J. Phys. Chem. Lett., 10, 870-876 (2019).
[3] L. Tavagnacco, M. Zanatta, E. Buratti et al., Chemical Science, 15, 9249-9257 (2024).
[4] N. Gnan, L. Rovigatti, M. Bergman, E. Zaccarelli, Macromolecules, 50, 8777-8786 (2017).
[5] L. Tavagnacco, E. Buratti, J. Vialetto, et al., Small, 21, e09795 (2025).