Proton transverse relaxation time (T2) and molecular self-diffusion coefficient (D) n.m.r. measurements of water in three hydrogels based on poly(2-hydroxyethyl-methacrylate) (pHEMA) have been performed in order to investigate the state of water and its interaction with the polymer network. Measured T2 values are discussed and quantitatively interpreted by assuming the chemical exchange process between water protons and hydroxyl protons of polymer chains as the major relaxation source, with no recourse to the bound water concept. The pseudo first-order kinetic constants and the activation energies for the exchange process in the different hydrogels have been calculated. The Pulsed Field Gradient (PFG) spin-echo technique has been used to measure diffusivity of water internal to the hydrogels; for hydrogels surrounded by external water, PFG multiple spin-echo experiments at different echo times and subsequent Diffusion Analysis by Relaxation-Time-Separated (DARTS) have been performed in order to obtain simultaneous determination of both internal and external water diffusion coefficients.

Investigation of water dynamic behaviour in poly(HEMA) and poly(HEMA-co-DHPMA) hydrogels by proton T2-relaxation time and self-diffusion coefficient NMR measurements / Delfini, Maurizio; R., Barbieri; M., Quaglia; Brosio, Elvino. - In: POLYMER. - ISSN 0032-3861. - STAMPA. - 39:5(1998), pp. 1059-1066. [10.1016/S0032-3861(97)00403-5]

Investigation of water dynamic behaviour in poly(HEMA) and poly(HEMA-co-DHPMA) hydrogels by proton T2-relaxation time and self-diffusion coefficient NMR measurements

DELFINI, Maurizio;BROSIO, Elvino
1998

Abstract

Proton transverse relaxation time (T2) and molecular self-diffusion coefficient (D) n.m.r. measurements of water in three hydrogels based on poly(2-hydroxyethyl-methacrylate) (pHEMA) have been performed in order to investigate the state of water and its interaction with the polymer network. Measured T2 values are discussed and quantitatively interpreted by assuming the chemical exchange process between water protons and hydroxyl protons of polymer chains as the major relaxation source, with no recourse to the bound water concept. The pseudo first-order kinetic constants and the activation energies for the exchange process in the different hydrogels have been calculated. The Pulsed Field Gradient (PFG) spin-echo technique has been used to measure diffusivity of water internal to the hydrogels; for hydrogels surrounded by external water, PFG multiple spin-echo experiments at different echo times and subsequent Diffusion Analysis by Relaxation-Time-Separated (DARTS) have been performed in order to obtain simultaneous determination of both internal and external water diffusion coefficients.
1998
poly(HEMA); hydrogels; NMR
01 Pubblicazione su rivista::01a Articolo in rivista
Investigation of water dynamic behaviour in poly(HEMA) and poly(HEMA-co-DHPMA) hydrogels by proton T2-relaxation time and self-diffusion coefficient NMR measurements / Delfini, Maurizio; R., Barbieri; M., Quaglia; Brosio, Elvino. - In: POLYMER. - ISSN 0032-3861. - STAMPA. - 39:5(1998), pp. 1059-1066. [10.1016/S0032-3861(97)00403-5]
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/15559
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 63
social impact