Poly(N-isopropylacrylamide) (PNIPAM) is a synthetic polymer that is widely studied for its thermoresponsive character. However, recent works also reported evidence of a low temperature (protein-like) dynamical transition around 225 K in concentrated PNIPAM suspensions, independently of the polymer architecture, i.e., both for linear chains and for microgels. In this work, we investigate water-polymer interactions by extensive differential scanning calorimetry (DSC) measurements of both systems, in order to understand the effect of the different topological structures on the solution behaviour, in particular regarding crystallization and melting processes. In addition, we compare protiated and deuterated micro gels, in both water and deuterated water. The DSC results are complemented by dynamic light scattering experiments, which confirm that the selective isotopic substitution differently affects the solution behaviour. Our findings highlight the important role played by the polymer architecture on the solution behaviour: indeed, microgels turn out to be more efficient confining agents, able to avoid water crystallization in a wider concentration range with respect to linear chains. Altogether, the present data will be valuable to interpret future low-temperature investigations of PNIPAM dispersions, particularly by neutron scattering experiments.

Buratti, E., Tavagnacco, L., Zanatta, M., Chiessi, E., Buoso, S., Franco, S., et al. (2022). The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions. JOURNAL OF MOLECULAR LIQUIDS, 355 [10.1016/j.molliq.2022.118924].

The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions

E. Chiessi;
2022

Abstract

Poly(N-isopropylacrylamide) (PNIPAM) is a synthetic polymer that is widely studied for its thermoresponsive character. However, recent works also reported evidence of a low temperature (protein-like) dynamical transition around 225 K in concentrated PNIPAM suspensions, independently of the polymer architecture, i.e., both for linear chains and for microgels. In this work, we investigate water-polymer interactions by extensive differential scanning calorimetry (DSC) measurements of both systems, in order to understand the effect of the different topological structures on the solution behaviour, in particular regarding crystallization and melting processes. In addition, we compare protiated and deuterated micro gels, in both water and deuterated water. The DSC results are complemented by dynamic light scattering experiments, which confirm that the selective isotopic substitution differently affects the solution behaviour. Our findings highlight the important role played by the polymer architecture on the solution behaviour: indeed, microgels turn out to be more efficient confining agents, able to avoid water crystallization in a wider concentration range with respect to linear chains. Altogether, the present data will be valuable to interpret future low-temperature investigations of PNIPAM dispersions, particularly by neutron scattering experiments.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore CHIM/02
English
Water
Crystallization
PNIPAM
Microgels
Polymer structure
Buratti, E., Tavagnacco, L., Zanatta, M., Chiessi, E., Buoso, S., Franco, S., et al. (2022). The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions. JOURNAL OF MOLECULAR LIQUIDS, 355 [10.1016/j.molliq.2022.118924].
Buratti, E; Tavagnacco, L; Zanatta, M; Chiessi, E; Buoso, S; Franco, S; Ruzicka, B; Angelini, R; Orecchini, A; Bertoldo, M; Zaccarelli, E
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/307895
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