液晶弹性体精.ppt

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1、液晶弹性体第1页，本讲稿共10页Contents1.Introduction2.What is LCEs3.Actuators based on LCEs 3.1.Actuators based on thermally actuated LCEs 3.2.Actuators based on photo-mechanically actuated LCEs 3.3.Actuators based on photo-thermo-mechanically actuated LCEs4.Summary 第2页，本讲稿共10页1.IntroductionFig 1.Fig 1.The difere

2、nt kinds of actuator materials both in natural and synthetic systemsSmart materials:There is a group of materials capable of responding to external stimuli with mechanical deformation.LCEs:LCEs:LCEs are novel materials among the polymer smart materials.They have properties of both liquid crystals an

3、d elastomers:the self-organization nature of liquid crystal systems and the flexibility stemming from the elasticity of polymer networks allow for large and reversible anisotropic dimensional changes in response to applied stimuli.第3页，本讲稿共10页2.What is LCEs LCEs are cross-linked polymer networks that

4、 contain rigid,anisotropic mesogenic units mesogenic units incorporated into the polymer chainspolymer chains.Due to the anisotropic nature of these units,the materials exhibit a liquid crystalline structure in which the mesogenic units have a certain orientational order but remain individually mobi

5、le and thus could flow with respect to one another.YZXRRMNMesogenic unitK K107 N N116 I IExample:(a)(b)(c)Fig 2.Fig 2.Schematic representation of different types of LCEs:(a)main chain LCEs;(b)side chain LCEs;(c)combined LCEs第4页，本讲稿共10页3.Actuators based on LCEs 3.1.Actuators based on thermally actuat

6、ed LCEsFig 3.Fig 3.Micrometer-sized nematic LCE actuators consisting of a pillar array.(a)Experimental setup used to prepare the responsive pillars.(b)Top view(under an optical microscope)of the pillar pattern obtained by the imprint in the nematic liquid crystal elastomer.(Inset)Zoom on the structu

7、re(pillar diameter=20mm)1.1 Buguin A,Li M H,Silberzan P,et al.Journal of the American Chemical Society,2006,128(4):1088-1089.第5页，本讲稿共10页3.2.Actuators based on photo-mechanically actuated LCEs3.Actuators based on LCEs Fig 4.Fig 4.(a)A schematic representing the assembled prototype of a micropump.(b)P

8、hoto of the experimental prototype(1)inlet,(2)press plate,(3)photodeformable material,(4)outlet,(5)pump membrane,and(6)pump chamber).(c)The photodeformable film on the pump membrane(1)press plate,(2)photodeformablefilm,(3)pump membrane,and(4)pump chamber).22 Chen M,Xing X,Liu Z,et al.Applied Physics

9、 A,2010,100(1):39-43.第6页，本讲稿共10页3.Actuators based on LCEs Fig 5.Fig 5.A light-driven plastic motor with an LCE laminated film.(a)Schematic illustration of a light-driven plastic motor system,showing the relationship between light irradiation positions and rotation direction.(b)Series of photographs

10、showing time profiles of the rotation of the light-driven plastic motor with the LCE laminated film induced by simultaneous irradiation with UV(366 nm,240 mW cm-2)and visible light(500 nm,120 mW cm-2)at room temperature 33 Yamada M,Kondo M,Mamiya J,et al.Angewandte Chemie International Edition,2008,

11、47(27):4986-4988.第7页，本讲稿共10页3.Actuators based on LCEs 3.3 Actuators based on photo-thermo-mechanically actuated LCEsFig 6.Fig 6.Optical images of photo-actuation of a blank LCE and an SWCNTLCE nanocompositefilm.The films have dimensions of 4 cm 0.5 cm0.7 mm.The irradiation intensity of the white lig

12、ht is 230 mW cm-2.(a)The initial state of the blank LCE and SWCNTLCE nanocompositefilms.(b)Comparison of the two films under irradiation.The blank LCE does not deform after being illuminated for several minutes.In contrast,the SWCNTLCE nanocompositefilm starts to contract conspicuously after about 5

13、 seconds,and reaches the stable length,which is about 2/3 of the initial length,after about 10 seconds.(c)The SWCNTLCE nanocomposite film recovers to its initial length in about 9 seconds after the light source is switched off.第8页，本讲稿共10页4.Summary LCEsLCEs are particularly promising materials for ar

14、tificial muscles,micro-robots and MEMS.In these systems not only 2D but also 3D motion has now been achieved,and a variety of actuation modes have been developed,which are competitive and promising for many applications as soft actuators.第9页，本讲稿共10页Thanks for your attention!Thanks for your attention!第10页，本讲稿共10页