Thermoresponsive copolymer microgels synthesized via single-step precipitation polymerization: random or block structure?

Fuente: arXiv
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Main Authors: Tavagnacco, Letizia, Buratti, Elena, Vialetto, Jacopo, Brasili, Francesco, Ballin, Elisa, Schwärzer, Kuno, Mata, Jitendra, Di Carmine, Graziano, Bertoldo, Monica, Chiessi, Ester, Laurati, Marco, Zaccarelli, Emanuela
Format: Preprint
Published: 2025
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author Tavagnacco, Letizia
Buratti, Elena
Vialetto, Jacopo
Brasili, Francesco
Ballin, Elisa
Schwärzer, Kuno
Mata, Jitendra
Di Carmine, Graziano
Bertoldo, Monica
Chiessi, Ester
Laurati, Marco
Zaccarelli, Emanuela
author_facet Tavagnacco, Letizia
Buratti, Elena
Vialetto, Jacopo
Brasili, Francesco
Ballin, Elisa
Schwärzer, Kuno
Mata, Jitendra
Di Carmine, Graziano
Bertoldo, Monica
Chiessi, Ester
Laurati, Marco
Zaccarelli, Emanuela
contents The inner structure of polymeric particles critically influences their phase behavior and functionality, governing their mechanical properties and their physical and chemical interactions. For thermoresponsive microgels, i.e. colloidal particles comprising a crosslinked polymer network that undergo a volume transition upon temperature changes, structural control is key to tailor the material responsivity and broaden the range of applications. In this work, we present a comprehensive investigation of the internal structure of poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide), P(NIPAM-co-NIPMAM), copolymer microgels, combining small-angle neutron scattering (SANS), dynamic light scattering (DLS), and nuclear magnetic resonance (NMR) measurements with multi-scale simulations. By synthesizing different samples, we probe the microgels swelling behavior, revealing distinct signatures of the individual polymers. To elucidate their internal distribution, we perform monomer-resolved microgel simulations across different copolymer models. A direct comparison between experimental and numerical form factors under different, neutron-selective conditions provides evidence of a preferential organization into block structures rather than a random arrangement. These results are confirmed by 13C-NMR which reveals the clear presence of NIPAM blocks within a more random arrangement of the remaining monomers and by atomistic molecular dynamics simulations on copolymer chains, which also shed light on a possible origin in the dependence of the hydrogen bonding capability on the local environment. These findings provide a detailed microscopic picture of the inner architecture of P(NIPAM-co-NIPMAM) microgels, revealing an unexpected structural organization that may be generalized to other copolymer systems and could be promising to tailor microgel design and enhance control of material responsivity.
format Preprint
id arxiv_https___arxiv_org_abs_2508_04246
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Thermoresponsive copolymer microgels synthesized via single-step precipitation polymerization: random or block structure?
Tavagnacco, Letizia
Buratti, Elena
Vialetto, Jacopo
Brasili, Francesco
Ballin, Elisa
Schwärzer, Kuno
Mata, Jitendra
Di Carmine, Graziano
Bertoldo, Monica
Chiessi, Ester
Laurati, Marco
Zaccarelli, Emanuela
Soft Condensed Matter
The inner structure of polymeric particles critically influences their phase behavior and functionality, governing their mechanical properties and their physical and chemical interactions. For thermoresponsive microgels, i.e. colloidal particles comprising a crosslinked polymer network that undergo a volume transition upon temperature changes, structural control is key to tailor the material responsivity and broaden the range of applications. In this work, we present a comprehensive investigation of the internal structure of poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide), P(NIPAM-co-NIPMAM), copolymer microgels, combining small-angle neutron scattering (SANS), dynamic light scattering (DLS), and nuclear magnetic resonance (NMR) measurements with multi-scale simulations. By synthesizing different samples, we probe the microgels swelling behavior, revealing distinct signatures of the individual polymers. To elucidate their internal distribution, we perform monomer-resolved microgel simulations across different copolymer models. A direct comparison between experimental and numerical form factors under different, neutron-selective conditions provides evidence of a preferential organization into block structures rather than a random arrangement. These results are confirmed by 13C-NMR which reveals the clear presence of NIPAM blocks within a more random arrangement of the remaining monomers and by atomistic molecular dynamics simulations on copolymer chains, which also shed light on a possible origin in the dependence of the hydrogen bonding capability on the local environment. These findings provide a detailed microscopic picture of the inner architecture of P(NIPAM-co-NIPMAM) microgels, revealing an unexpected structural organization that may be generalized to other copolymer systems and could be promising to tailor microgel design and enhance control of material responsivity.
title Thermoresponsive copolymer microgels synthesized via single-step precipitation polymerization: random or block structure?
topic Soft Condensed Matter
url https://arxiv.org/abs/2508.04246