Realization of Smart Window with Memory Effect by Mixing Hollow Sphere Mesoporous Silica with Nematic Liquid Crystal

• Main Authors: Li-JieLin, 林莉婕
• Other Authors: Hong-Ping Lin
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/svyt4t

碩士 === 國立成功大學 === 化學系 === 105 === Existing liquid crystal smart windows require a continuous power supply to maintain a transparent state, and therefore incur a high power consumption. In this study, a practical energy-saving strategy is demonstrated by mixing 5CB nematic liquid crystal with hollow sphere mesoporous silica (HSMS) synthesized using a soft-templating method under pH=5.5–6.0 and then hydrophobically modified by chlorotrimethylsilane. The optical microscopy observations show that the hierarchical sphere structure divides the 5CB molecules into a large number of scattering regions, and therefore produces a dense opaque state. For example, 7.5 wt% HSMS addition results in an opaque state with a transmittance as low as 23%. However, given an applied voltage of 80 V, the 5CB molecules are almost perfectly aligned and a transparent state with a saturated transmittance of 100% is obtained. Notably, the weak anchoring force between the hydrophobically modified HSMS and the liquid crystal material resists the realignment of the 5CB molecules following the removal of the electrical field and results in a residual transmittance of over 90% for more than 2 hours. Overall, the results presented in this study show that the addition of HSMS material to 5CB liquid crystal enhances the memory effect and therefore makes possible the realization of smart windows with a reduced energy consumption.