Figure 9.
Schematic illustration of the internal fracture process and redistribution of the polymer network under a cyclic load. The network of NIPA gel is mainly composed of main chains in black curves by crosslinker (black dot). The red and blue curves stand for the weak chains generated by hydrophilic moieties (–CONH–) and hydrophobic moieties (–CH(CH3)2), respectively. (a,d) is the initial state of NIPA hydrogel before tension; (b,e) and (c,f) are internal fracture process and redistribution of polymer chains below the LCST above the LCST, respectively.