| Popis: |
Shape memory polyurethanes (SMPUs), which have fast been developing lately, can transfer back to the original shape from their temporary shapes upon stimulus, such as light, electricity, heat, humidity, magnetic, and chemical environment. Though light acts as a clean and non-contact stimulus for inducing changes in temporary shapes, light-induced deformations cannot be fixed under our ambient conditions. Herein, a new kind of shape memory polyurethanes was prepared by chemically cross-linking of polyethylene glycol and 4,4′-dihydroxyazobenzene with 1,3,5,7-tetrahydroxyadamantane in one-step method. The sythesized SMPUs are capable of shape deformation under ultraviolet-light (UV-light) and shape fixation in visible light and then the original shape can be recovered in room temperature water. Owing to the outstanding UV-light and water effect of SMPUs, the SMPUs exhibit a rapid UV-light response shape memory process and a rapid recovery in water with the 4,4′-dihydroxyazobenzene content of 3.1 wt%. The study of the versatility of the synthesized SMPUs can expands the current understanding of the multi-stage stimuli-responsive features in both light- and water- induced SMPUs, illuminating a new mechanism of multi-stage stimuli-responsive shape memory effects. |
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