Reversible deformation of opal elastomers
Reversible deformation of opal elastomers
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DOI：
10.1021/cm062582a
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发表时间：
2007-11-13
影响因子：
8.6
通讯作者：
Hellmann, Goetz P.
中科院分区：
文献类型：
--
作者：
Viel, Benjamin;Ruhl, Tilmann;Hellmann, Goetz P.
人造蛋白石是由亚微观尺寸的单分散二氧化硅或聚合物微珠结晶而成。珠子自组织成面心立方(FCC)晶格，光从该晶格有选择地反射波长。在0.15-0.3微米的直径处，通过来自晶格的i面的衍射从白光中挑选出颜色，反射的颜色取决于间距a i。对于核壳(CS)珠子的弹性蛋白石薄膜，这种间距和颜色可以通过变形来改变。到目前为止，这种机械变色效应只在由没有化学互连的珠子制成的蛋白石上进行了研究，因此变形部分是不可逆的。在这项研究中，用熔体流动技术制备了聚合物核壳微珠的蛋白石薄膜。之后，这些电影被照片交叉链接。然而，它们确实是可逆变形的，具有机械滞后效应。应变的面心立方晶格引起反射颜色的蓝移，这表明了硬球变形机制。这种变化足够强烈，只需几个百分点的应变就可以打开和关闭单色光。
Synthetic opals result from the crystallization of monodisperse silica or polymer beads of submicroscopic size. The beads self-organize to the face-centered cubic (fcc) lattice from which light is reflected wavelength selectively. At diameters of 0.15-0.3 mu m, colors are singled out of white light by diffraction from the I I I plane of the lattice, the reflected color depending on the spacing a I I,. With elastic opal films of core-shell (CS) beads, this spacing and, thereby, the color can be changed by deformation. This mechanochromic effect has so far been studied only on opals made of beads that were not chemically interconnected so the deformation was partly irreversible. In this study, opal films of polymeric core-shell beads were prepared by a melt-flow technique developed earlier in this institute. Afterward, the films were photo-cross-linked. They deformed indeed reversibly, however, with mechanical hysteresis effects. The strained fcc lattice causes a blue shift of the reflected color, which is indicative of a hardsphere deformation mechanism. The shift is strong enough to switch monochromatic light on and off by only a few percent strain.