聚苯乙烯微米球摻混向列型液晶之電流變效果探討

本研究利用分散聚合法製作出球型微米粒徑大小之聚苯乙烯，並藉由改變穩定劑(Polyvinylpyrrolidone)比例來控制其粒徑大小。分別利用不同粒徑大小之微米球作為固相粒子，以不同比例摻入相列型液晶中製成均相電流變液體。將均相電流變液施加不同強度之電場，觀測相列型液晶之電流變效果及不同粒徑大小聚苯乙烯微米球以不同比例摻入後對其電流變效果之影響。結果利用掃描式電子顯微鏡(SEM)及傅立葉轉換紅外線光譜儀(FTIR)可證實球型微米粒徑之聚苯乙烯確有成功合成且形狀大小均一，而改變穩定劑(Polyvinylpyrrolidone)比例亦可有效控制聚苯乙烯微米球之粒徑大小。相較於純的相列型液晶，首先摻入20wt%不同粒徑大小之聚苯乙烯微米球後發現其剪應力(shear stress)相對於純的向列型液晶並無改變，且電流變效果亦不明顯。當聚苯乙烯微米球摻混比例達30wt%後，電流變液之剪應力及黏度大幅上升，且電流變流體開始出現屈服應力(yield stress)，具明顯且穩定之電流變效果。隨摻入之聚苯乙烯微米球比例上升，其剪應力亦相對提高。而本篇另一探討重點為聚苯乙烯微米球之粒徑大小對電流變效果之影響。隨聚苯乙烯微米球之粒徑越小，發現其電流變效果相對越佳。表示聚苯乙烯微米球達到30wt%後能夠開始影響向列型液晶分子之排列，使其於電場作用下結構更加穩固。且粒徑越小之聚苯乙烯微米球與液晶分子間之作用力越強，從而提升電流變液之電流變效果。

關鍵字

向列型液晶；聚苯乙烯微米球；分散聚合；液晶電流變；電流變

並列摘要

This study is the production of micron diameter size spherical polystyrene by dispersion polymerization and the investigation of its electrorheological properties. we synthesis polystyrene with controled particle size by changing the stabilizer(Polyvinylpyrrolidone) ratio. We use polystyrene with different particle sizes and concentration as the solid phase particles, and blend it with nematic liquid crystal to manufacture a homogeneous electrorheological fluid. Results of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) confirm micron spherical particle of polystyrene does have successfully synthesized with uniform size and shape. Changing stabilizer ratio can control the particle size of polystyrene microspheres successfully. Compared to pure nematic liquid crystal, the more electric field applied the higher shear stress and viscosity were found in homogeneous electrorheological fluid.Shear stress were increased with concentration of polystyrene of homogeneous electrorheological fluid. The smaller particle perform more greater ER effect.

並列關鍵字

Nematic liquid crystal ； Polystyrene microspheres ； Dispersion polymerization ； Liquid crystal electrorheological ； Electrorheological

參考文獻

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國際替代計量

聚苯乙烯微米球摻混向列型液晶之電流變效果探討

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