Sliding Crosslinked Thermoresponsive Materials: Polypseudorotaxanes Made of Poly(N-Isopropylacrylamide) and Acrylamide-γ-Cyclodextrin.

Giulio Malucelli,Jvan Dore,Valeria Alzari,Alberto Mariani,Davide Sanna,Mariella Rassu,Daniele Nuvoli

doi:10.3389/fchem.2018.00585

Abstract

Novel polypseudorotaxanes (PPR) based on poly(N-isopropylacrylamide) (PNIPAAm) and acrylamide-γ-cyclodextrin (AγCD) are successfully synthesized. AγCD gives rise to sliding crosslinking systems and influences the thermoresponsive and swelling behavior of PNIPAAm hydrogels. Namely, their lower critical solution temperature (LCST) can be tuned up to 38°C, thus making the resulting materials of great interest in biomedical applications. Also, AγCD influences the thermal and mechanical properties of hydrogels, by affecting the Tg and E modulus values.

Highlights

IntroductionCyclodextrins (CDs) are ring-shaped molecules obtained by degradation of starch, composed of five or more 1-4-linked α-D-glucopyranoside units, as in amylose
Polyrotaxanes (PRs) are among the most thoroughly investigated types of supramolecular polymers, consisting of one or more cyclic molecules threaded onto a linear polymer axis and endcapped with bulky moieties on both terminals of the macromolecular chain (Harada et al, 1999, 2009; Huang and Gibson, 2005; Wenz et al, 2006; Araki and Ito, 2007; Li and Loh, 2008).Cyclodextrins (CDs) are ring-shaped molecules obtained by degradation of starch, composed of five or more 1-4-linked α-D-glucopyranoside units, as in amylose
The γ-CD used in this work was monoacrylated, in order to act as a NIPAAm comonomer, being it eventually covalently linked to PNIPAAm chains

Summary

Introduction

Cyclodextrins (CDs) are ring-shaped molecules obtained by degradation of starch, composed of five or more 1-4-linked α-D-glucopyranoside units, as in amylose. Thanks to their non-toxicity, not absorbability in the upper gastrointestinal tract and their capacity to be metabolized by the colon microflora, their main use is in food industry (Del Valle, 2004; Marques, 2010). Α-CDs, β-CDs, and γ-CDs are 6-, 7-, and 8-membered sugar ring molecules, respectively

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