Co-flow microfluidic synthesis of liquid crystalline actuating Janus particles
Co-flow microfluidic synthesis of liquid crystalline actuating Janus particles
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DOI：
10.1039/c6tc03378d
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发表时间：
2016-10-07
影响因子：
6.4
通讯作者：
Zentel, R.
中科院分区：
文献类型：
--
作者：
Hessberger, T.;Braun, L. B.;Zentel, R.
在这篇文章中，微流控合成和表征的微米尺寸的驱动Janus粒子含有液晶弹性体（LCE）。在一侧，这些Janus颗粒由疏水性液晶部分组成，在热致相变期间具有强烈的形状变化，而另一侧包含亲水性聚丙烯酸网络。该合成是基于两种不混溶的单体混合物在连续流动的硅油中的分散，使用两个并排的玻璃毛细管形成不同形态的Janus微滴。此外，Janus颗粒的形态的系统调整以及致动特性的优化是通过精确控制和微流体参数的变化来进行的。通过偏光显微镜（POM）研究了颗粒的致动特性，其中在棒状Janus颗粒的相变过程中，LCE的相对长度变化高达52%。进一步的广角X射线散射（WAXS）测量验证了介晶在双极指向矢场中的取向，这对应于所观察到的Janus粒子形状变化的几何形状。
In this article the microfluidic synthesis and characterization of micrometer sized actuating Janus particles containing a liquid crystalline elastomer (LCE) is presented. On one side these Janus particles consist of a hydrophobic liquid crystalline part, featuring strong shape changes during the thermotropic phase transition, whereas the other side contains a hydrophilic potyacrytamide network. The synthesis is based upon the dispersion of two immiscible monomer mixtures in a continuously flowing silicone oil, using two glass capillaries side by side to form Janus microdroplets of different morphologies. Furthermore, the systematic adjustment of the morphology of the Janus particles as well as the optimization of the actuation properties is conducted by precise control and variation of the microfluidic parameters. The actuation properties of the particles are studied by polarized optical microscopy (POM), in which relative length changes up to 52% are investigated for the elongation of LCEs during the phase transition in rodlike Janus particles. Further wide-angle X-ray scattering (WAXS) measurements verify the mesogen's orientation in a bipolar director field, which corresponds to the observed geometry of the Janus particle's shape changes.