title: Terahertz Time-Domain Spectroscopy of Thermoresponsive Polymers in Aqueous Solution.
abstract: The behavior of highly concentrated aqueous solutions of two thermoresponsive polymers poly(N-isopropylacrylamide) (PNIPAm) and poly(N-vinylcaprolactam) (PVCL) have been investigated by terahertz time-domain spectroscopy (THz-TDS). Measurements have been performed for concentrations up to 20 wt %, over a frequency range from 0.3 to 1.5 THz and for temperatures from 20 to 45 °C including the zone for lower critical solution temperature (LCST). THz-TDS enables the study of the behavior of water present in the solution (i.e., free or bound to the polymer). From these measurements, in addition to phase transition temperature, thermodynamic data such as variation of enthalpy and entropy can be inferred. Thanks to these data, further insights upon the mechanism involved during the dehydration phenomenon were obtained. These results were compared to the ones issued from dynamic light scattering, spectroscopy, or microscopy techniques to underline the interest to use THz-TDS as a powerful tool to characterize the behavior of thermoresponsive polymers in highly concentrated solutions.
authors.affiliation: Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse , 31055 Toulouse Cedex 4, France.|Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Serin
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Hong Hanh
authors.initials: HH
authors.lastname: Nguyen
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Marty
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Micheau
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Gernigon
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Mingotaud
authors.affiliation: Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse , 31055 Toulouse Cedex 4, France.
authors.forename: Damienne
authors.initials: D
authors.lastname: Bajon
authors.affiliation: Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse , 31055 Toulouse Cedex 4, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Soulet
authors.affiliation: Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Université de Toulouse , 31055 Toulouse Cedex 4, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Massenot
authors.affiliation: Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062 Toulouse Cedex 9, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Coudret