Study On The Surface Chemical Modification Of Stimulating Responsive Polymer Thin Films

Stimuli-responsive films can respond to external stimuli and generate the corresponding signal feedback.Normally,they can transfer stimuli such as temperature,humidity,light,and electromagnetic fields into kinematic deformation.The smart film-based actuators are widely applied in flexible sensors,biomimetics,robotics.Therefore,the development of smart film with high sensibility,super durability,fatigue resistance and controllable kinematics is of great significance in the soft actuating and sensing fieldsIn this paper,a series of surface-patterning methods for single-layered film are reported,which endow the film actuator controllable shape deformation in response to external stimuli On the basis of ensuring the controllable kinematics,the bending force of the films are further improved so as to overcome the drawbacks of single layer film,and set a solid foundation for the application of the film in sensing and actuators,which is briefly describe as follow Polyvinylidene fluoride(PVDF)is sensitive to acetone vapors that can be shape deformed with its multi-fluorine structure.The PVDF film actuator was created by alignment Fe particles(FePs)into PVDF matric in a strong magnetic field.Followed by stretching the PVDF film composite into necking structure.The necking induces more-directional alignments of FePs and further crystallization of PVDF,so that bringing PVDF/FePs actuator with anisotropic elastic tensors,resulting in controllable shape deformation upon sorption of acetone vapors.Assisted by magnetic field,acetone-driven deformation can be transferred to directional movement by rolling over a substrate.Micropatterned PVDF/FePs actuator is stretchable and tough,with maximum stress reaching 160 MPa.The microstructure of thin film was analyzed by scanning electron microscope,combined with X ray diffraction and tensile test.This directional reversible fatigueless response is involved in a smart controller that exhibits promising potential for multistage detection of acetone vaporsIn addition,to further increase bending force of actuator upon acetone stimulation so as to broaden the application areas of thin film actuators,micro-patterned structure "soft-hard segment" prepared by solid polymerization on the basis of single layer thin film.The soft-hard structures lead to an unequal response that results in the shape-programmed deformation when exposed to acetone vapors.The actuator is elastic(strain:160%)and tough(stress:40 MPa)and can maintain its rapid,reversible,and shape-programmed motions for a few hours,even longer.The soft-hard structure enables the film actuator(3.5 mg)to give a contracting stress of 4 MPa that is used in an automatic device able to lift a cargo of 5.09 g,?1453 times heavier than the film itself.The power output reaches 474 J kg-1,?100 times higher than the reported soft actuators.This simple application indicates a potential for the soft actuator used in acetone vapor sensing devices.