Multistate and On-Demand Smart Windows
Multistate and On-Demand Smart Windows
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DOI：
10.1002/adma.201803847
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发表时间：
2018-10-25
影响因子：
29.4
通讯作者：
Yang, Shu
中科院分区：
文献类型：
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作者：
Kim, Hye-Na;Ge, Dengteng;Yang, Shu
复合薄膜由弹性聚（二甲基硅氧烷）薄膜顶部的褶皱和嵌入底部的薄层二氧化硅颗粒组成，制备为按需机械响应智能窗口。通过仔细改变褶皱几何形状、二氧化硅颗粒大小和拉伸应变，在相对较小的应变（小至10%）下，在可见光至近红外范围内实现了不同的初始光学状态和较大程度的光学透过率变化。10%预应变试样的折皱较浅，幅度较小，初始透光率中等（60.5%），在预应变水平拉伸时，在550 nm处透光率最高，达到86.4%。拉伸超过应变前水平，在550 nm处透射率急剧下降，应变增加10%和30%，透射率分别下降39.7%和70.8%。光学透过率的大幅下降是二次褶皱的形成和颗粒周围纳米空隙的共同作用的结果。20%预应变试样具有中等幅度的褶皱，初始状态下透光率为36.9%，拉伸至预应变水平时，在550 nm处透光率最高，为71.5%。进一步拉伸导致不透明度增加，类似于从10%预应变样品中看到的。
Composite films consisting of wrinkles on top of the elastomeric poly(dimethylsiloxane) film and a thin layer of silica particles embedded at the bottom is prepared as on-demand mechanoresponsive smart windows. By carefully varying the wrinkle geometry, silica particle size, and stretching strain, different initial optical states and a large degree of optical transmittance change in the visible to near infrared range with a relatively small strain (as small as 10%) is achieved. The 10% pre-strain sample has shallow wrinkles with a low amplitude and shows moderate transmittance (60.5%) initially and the highest transmittance of 86.4% at 550 nm when stretched at the pre-strain level. Stretching beyond the pre-strain level leads to a drastic decrease of the transmittance at 550 nm, 39.7% and 70.8% with an additional 10% and 30% strain, respectively. The large drop of optical transmittance is the result of combined effects from the formation of secondary wrinkles and nanovoids generated around the particles. The 20% pre-strain sample has wrinkles with a moderate amplitude, showing 36.9% transmittance in the initial state, and the highest transmittance of 71.5% at 550 nm when stretched to the pre-strain level. Further stretching leads to increased opacity similar to that seen from the 10% pre-strain sample.