Zhejiang superb team, who developed a fast response of the shape memory polymer / graphene composite material
A shape memory polymer can be modified in accordance with established procedures external stimulation, which makes it has a promising prospect in drivers, sensors, drug delivery and the like. Since the polymer material of low thermal conductivity itself, and the slow rate of movement of the chain, the response speed of the shape memory polymer material having a large gap remains other than shape memory material (e.g., a shape memory alloy). The main content Recently, Zhejiang University superb (Corporate Communication), Xu Zhen (Corporate Communication) team and the Marxist-Leninist (Corporate Communication) team and other partners to work together, breaking the speed of response problem. This work graphene airgel highly stretchable as a template to build structures polycaprolactone (polycaprolactone, PCL) thin films (2.5-60nm) made of a shape memory network in its interior. Wherein the graphene nanonetwork energy conversion and energy as a quick injection channel, PCL nanonetwork energy transfer and rapid deformation as the carrier. Such airgel nanocomposites having PCL / graphene interpenetrating network structure under electrical stimulation response time of 50 ms, the response speed of 175 ± 40 mm s-1, a maximum deformation of about 100%. The work \”Millisecond Responseof Shape Memory Polymer Nanocomposite Aerogel Powered by Stretchable GrapheneFramework\” was published in ACS Nano. 
view of a traditional shape memory polymer blends and composite airgel composites (herein) is a schematic view of a conventional shape memory polymer composite material to use for producing a conductive additive blending method, resulting in the conductive network to a base SMP heat conduction distance is generally in the micron level. However, the thermal conductivity of polymer materials are generally low (for example, as used herein, polycaprolactone PC, ~ 0.3 W mK-1), which leads to the response time of the conventional shape memory polymer blend is generally in seconds level and above. This study is a highly stretchable airgel as a template to build nanoscale polycaprolactone continuous layer on the surface thereof nanometers (2.5-60 nm), to reduce the heat transfer distance. 
Figure II .a-e, the microstructure of the composite structure of this Institute airgel materials can be used to pullAirgel is a stretch team in 2018 \”Highly Stretchable Carbon Aerogels\” work (Nat.Commun.2018,9,881) are expanded based ( \”Nature Communications\” Zhejiang University Professor Gao Chao team developed full high tensile carbon aerogels plastic elastomers). Using graphene airgel as injection and rapid energy conversion skeleton SMP achieve rapid phase transition. Finally obtained millisecond response time (50 ms), ultra-light composite airgel material elongation of 100% or more. 
Figure 3. Shape response performance graphene / PCL composite airgel while the work situ TEM sample rod Wang Hongtao TF Zhejiang College of Aeronautics and Astronautics developed observed airgel composite consisting essentially of units – shape memory behavior graphene / PCL composite sheet under electrical stimulation. 
Figure 4. lightweight airgel composite material of the shape memory behavior of graphene / PCL composite monolithic the rapid response has broad application prospects, may be designed for ultra fast fuses to protect the delicate circuits in case of overload next, the open circuit within 134 ms, the protection of electrical appliances. It also can be combined with an electromagnet, as the micro-oscillator. 
Figure V. PhD Professor Gao Chao application of graphene / PCL composite airgel Guo is the first author of the paper, PhD professor of Marxism-Zheng Wen is the second author of the paper. Professor of Polymer Science Professor Ma Liehu aerospace Wang Hongtao School of Zhejiang University, Zhejiang University, provides strong support and cooperation guidance for the completion of this work. Paper was funded by the National Key R & D Program, National Natural Science Foundation of China and other related funds.
