Harvey C L M, Terentjev E M
Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
Eur Phys J E Soft Matter. 2007 Jun;23(2):185-9. doi: 10.1140/epje/i2007-10170-y.
Changing the orientational order in liquid-crystal elastomers leads to internal stresses and changes of the sample shape. When this effect is induced by light, due to photoisomerization of constituent molecular moieties, the photomechanical actuation results. We investigate quantitatively how the intensity and the polarization of light affect photoactuation. By studying dissolved, as well as covalently bonded azo-dyes, we determine the changes in absorption and the response kinetics. For the first time we compare the response of aligned monodomain, and randomly disordered polydomain nematic elastomers, and demonstrate that both have a comparable photoresponse, strongly dependent on the polarization of light. Polarization-dependent photoactuation in polydomain elastomers gives an unambiguous proof of its mechanism since it is the only experiment that distinguishes from the associated thermal effects.
改变液晶弹性体中的取向顺序会导致内部应力和样品形状的变化。当这种效应由光诱导时，由于组成分子部分的光异构化，会产生光机械驱动。我们定量研究光的强度和偏振如何影响光驱动。通过研究溶解的以及共价键合的偶氮染料，我们确定了吸收的变化和响应动力学。我们首次比较了取向单畴和随机无序多畴向列弹性体的响应，并证明两者具有可比的光响应，且强烈依赖于光的偏振。多畴弹性体中依赖偏振的光驱动为其机制提供了明确的证据，因为这是唯一能与相关热效应区分开来的实验。
