Preparation of a High-Strength Hydrogel with Slidable and Tunable Potential Functionalization Sites

A hydrogel with tunable potential functionalization sites has been successfully prepared. As potential functionalization sites, (2-hydroxypropyl)-alpha-CDs (Hy-alpha-CDs) were introduced into the network of tetrahedron-like poly(ethylene glycol) (tetra-PEG) gel through supramolecular chemistry. In the stage of complexation, poly-pseudo-rotaxane consisting of tetra-PEG macromonomer and Hy-alpha-CD formed in pregel solution. The dynamic complexation process and the structure of the poly-pseudo-rotaxane were investigated by NMR experiment. In the stage of gelation, some cross-linking reactions were completed through click chemistry. The structures and mechanical properties of the resultant hydrogels were characterized by ATR-FTIR, XPS, SEM, and compression test in detail. The number of Hy-a-CD introduced into the hydrogel is related closely to the structure of the poly-pseudo-rotaxane and can be controlled easily by tuning the feed ratio. Anthracene as an example of function was introduced into the hydrogel through Hy-alpha-CD to preliminarily demonstrate the validity of the potential functionalization site in the last, and the hydrogel also has the capacity for further diverse functionalization.