Polarization-controlled, photodriven bending in monodomain liquid crystal elastomer cantilevers

Curvature in nematic elastica responding to light and heat

“…We suggest (Corbett & Warner 2008) a syn-clastic response when the director is normal to the cantilever or when the cantilever is made of a polydomain nematic and is illuminated by unpolarized light. In general, the mechanics of polydomain nematics is determined by the polarization of light (Yu et al 2003;Corbett & Warner 2006;Harvey & Terentjev 2007;White et al 2009) and subtle control is thereby afforded.…”

Photomechanical Response of Composite Structures Built from Azobenzene Liquid Crystal Polymer Networks

“…Azobenzene liquid crystal polymer networks of a variety of domain structures and orientations were prepared as specified in previous reports (monodomain [10,14], polydomain [8,9], twisted nematic [24], polyimide [32]). In general, a mixture composed of 20 wt% 4-4'-bis[6-(acryoloxy)hexyloxy]-azobenzene (2azo, BEAM Engineering for Advanced Measurements) was mixed with RM257 (Merck) (chemical structures shown in Figure 1).…”

“…Photomechanical responses in azo-LCN materials have been most often observed as uniaxial contraction of a film (typically elastomers-large strain) [6,[17][18][19] or bending of a cantilever (typically glasses-lower strain) [7][8][9][10][11][12][13][14][15][16]. The magnitude or directionality of the photomechanical response of azo-LCN materials has repeatedly been controlled by the alignment of the linear polarization of the actinic source and the sample geometry [8,9,11,12,[14][15][16].…”

“…The magnitude or directionality of the photomechanical response of azo-LCN materials has repeatedly been controlled by the alignment of the linear polarization of the actinic source and the sample geometry [8,9,11,12,[14][15][16]. Theoreticians have found the unique blend of polymer physics, photochemistry, and mechanics a rich challenge [18,[20][21][22].…”

“…Since this work, considerable effort has pursued a variety of aspects of this unique means of transducing energy in primarily liquid crystalline materials. Notably, this research has expanded into looking at glassy, azobenzene-functionalized liquid crystal polymers [7][8][9][10][11][12][13][14][15][16]. To capture both elastomeric and glassy liquid crystalline systems, we refer to the broader area as azobenzene-functionalized liquid crystal polymer networks (azo-LCN) and emphasize the glassy or elastomeric nature of the given chemistry.…”