Controllable Preparation And Photo-induced Behavior Of Polysiloxane Elastomer Nanocomposite Fibers

On account of actuation principle of flexible polymer optical-induced mechanical actuator and the research progress abreast of the times,in this dissertation,a series of nanocrystalline-based elastomer composite fibers that can have a reversible mechanical driven behavior to near infrared laser?NIR?irradiation was fabricated through design optimization.Besides,their structure and photo-induced mechanical response have been studied indepth.Including the following three aspects work:?1?Prepared gold nanorods?AuNRs?with uniform ratio?5.5?of length to diameter by traditional seed growing method.Choose hydroquinone instead of common used ascorbic acid as the weak reducing agent for trivalent gold ion in the growth solution,increase the degree of stable in growth solution and at the same time,improve the yield of gold nanorods.In order to reduce the toxicity caused by coating surfactant CTAB?hexadecyl trimethyl ammonium bromide?,preliminary prepared gold nanorods was modified with small molecule thiol compound for getting rid of CTAB by centrifugation.And the compatibility of gold nanorods with the polymer was improved effectively.Take advantage of the property of liquid silicone rubber that can have cross-link and then consolidation at high temperature,the gold nanorods/polydimethylsiloxane?AuNRs/PDMS?composite fibers with the filler of gold nanomaterial dispersed in the polymer matrix uniformly were fabricated successfully by solution spinning method.And the fibers are transparent with extremely toughness.Characterization showed that this kind of composite fiber can have a fast and reversible mechanical response to NIR irradiation,the wavelength is808 nm.Give tensile pre-strain?on fiber would induce varying degrees of orientation of fillers in the matrix.Under the irradiation,the fiber exhibited reversible behavior of extension when the pre-strain was less than 10%,and the output force of fiber to laser decreased with the increasing of?.While at high levels of pre-strain,larger than 10%,the fiber would contract swift and the output force increased with the increasing of?.Besides,composite fibers returned to the initial state immediately when the light was off.The response rate of the fibers to light showed a tendency to accelerate with the increasing of tensile pre-strain or the content of gold nanorods,the maximum response rate was up to 4.405 KPa s^-1.However,the saturation response time would decrease at the same time,reached saturated state in 14.4 s.In addition,the diameter of this sample composite fiber showed some obvious effect to its mechanical response behavior to light induced.The output force increased with the decreasing of fiber's diameter when it was less than 0.5 mm while larger than 0.5 mm,the output power decreased.?2?Make graphene oxide?GO?as filler in elastic matrix.Based on the property of GO that can be reduced at high temperature,reduced graphene oxide/polydimethylsiloxane?RGO/PDMS?composite fibers with different degree of RGO in matrix were prepared through solution spinning method at different reduction temperature under the same experimental conditions.Results showed that,RGO/PDMS composite fibers with varying degree of RGO can have a reversible response behavior and the tensile pre-strain dependence to NIR light which were similar to AuNRs/PDMS composite fibers.The higher the degree of pre-strain,fiber's output force to NIR light would be stronger and the response saturation time could be shorter.In 12.2 s can be achieved saturation within a maximum dynamic stress of 80KPa.Moreover,the higher the degree of reduction of graphene oxide,which meant the higher the content of grapheme in composite system,fiber's output force would also be greater.?3?Use molybdenum disulfide?MoS₂?and bismuth selenide?Bi₂Se₃?as fillers in the elastic matrix,prepare MoS₂/PDMS and Bi₂Se₃/PDMS composite fibers under the same conditions in?1?discuss the probability to fabricate and the influence of nano filler/PDMS to light induced dynamic.The characterization shows that the PDMS composite elastic fiber has a universality response to NIR light,all of them have a reversible response behavior and tensile pre-strain dependency which are similar to AuNRs/PDMS composite fibers.When the filler content was 0.5 wt%,the output force of the AuNRs/PDMS composite fiber was the largest,and the response rate was the fastest.The Bi₂Se₃/PDMS composite fiber was gray and transparent,and the light response output force was the smallest.