Synthesis and characterization of poly(2-hydroxyethylacrylate)/β-cyclodextrin hydrogels obtained by frontal polymerization

• Frontal polymerization was used to synthesize hydrogels containing β-cyclodextrins.
• Grafted and dispersed β-cyclodextrins affected hydrogel properties in different ways.
• Glass transition temperature increased for high amounts of grafted β-cyclodextrin.
• Hydrogel swelling ratio increased only for low concentrations of cyclodextrin.
• Grafted β-cyclodextrin acted as strong reinforcing agent.

For the first time, the synthesis of polymeric hydrogels containing cyclodextrins (CDs) obtained by frontal polymerization (FP) is reported. In particular, the effects of CDs on poly(2-hydroxyethylacrylate) hydrogel properties are investigated. In a first series of materials, β-cyclodextrin is dispersed into the polymer matrix, while in the second one acryloyl-β-cyclodextrin is grafted to poly(2-hydroxyethylacrylate) chains. FP parameters (front velocity and maximum temperature), swelling properties, glass transition temperatures and mechanical properties of the hydrogels are studied. Results show that both types of cyclodextrin influence the above properties, and the major effects are found for concentration higher than 1 mol% of acryloyl-β-cyclodextrin. Namely, a significant increase of glass transition temperature and of compression moduli are found. Finally, this study demonstrates that FP is a convenient technique to obtain CD-containing hydrogels, in which the type and amount of cyclodextrin can be suitably modulated to tune polymer properties, in function of the desired hydrogel applications.