Studies On The Preparation And Characterization Of Functional Hydrogels Based On β-cyclodextrin

In recent years, there are increasing reports on functional hydrogels based on cyclodextrins, most of them show stimuli-resposive or self-healing behaviours, but weak mechanical properties. Functional hydrogels with good mechanical properties based on β-cyclodextrin were synthesized in this thesis. The main contents of this thesis are desribed as follows:1. A chemical cross-linker β-CD-2AOI was first prepared using β-CD and AOI, then β-CD-2AOI can copolymerize with acrylamide(AM) to form transparent and highly stretchable hydrogels with water-responsive shape-memory behaviour. The highly stretchability is attributed to the big volume steric hindrance effect of β-CD-2AOI which is expected to result in relatively uniform three-dimensional network. By adjusting the concentration of the crosslinking agent, the gel’s breaking tensile strength and strain can be adjusted in the range of 30 kPa-110 kPa and 300%-1800%, respectively. Because β-CD and adamantane(Ada) can form inclusion complexation in water, a new covalent-non-covalent co-crosslinker β-CD-2AOI-Ada-ser-AOI was prepared to further increase the resulting gel’s strength.2. Macromolecular supramolecular crosslinker(MSCL) was first synthesized via inclusion complexation interaction between poly(β-CD) and Adamantane monomer. The supramolecular hydrogels are prepared by simple free-radical copolymerization of AM and MSCL. The obtained supramolecular hydrogels show extremely stretch, notch and stab resistant properties and excellent self-healing behaviour.3. Although the above described supramolecular hydrogels have many unique mechanical properties, their strength is weak. We further used BIS co-crosslinking or HEA copolymerization approaches to further enhance the above said hydrogels’ mechanical properties. The method of BIS co-crosslinking can efficiently increase the gel’s strength, but at the same time, it weakens the notch-insensitive and self-healing properties of the supramolecular gels. While, the HEA copolymerization technique not only enhances the gel’s mechanical strength, but also does not sacrifice the gel’s notch-insensitive and self-healing properties.