作者感谢德国科学基金会资助这项工作 (泽 230/24-1)。

1. 单驱动冰粒子的合成
<ol><li>
安装设备 注: 用于微流控装置的所有材料均为高效液相色谱供应和商用。<ol>
<li>配备玻璃水浴盘 [直径 (D): 190 毫米, 连接: 两个29/24 地面玻璃连接法兰安装] 与两个隔膜。拉刀两个隔膜与一个锥, 以适应一个管与外径 (OD) 的1/16 英寸通过开口孔。</li>
		<li>将1/16 英寸外径油管和相应的套圈接头连接到聚四氟乙烯管 (1.1 管) 的末端;外径: 1/16 英寸, 内径 (ID): 0.17 毫米, 长度 (L): 5 厘米), 贴上聚酰亚胺涂层二氧化硅毛细管 (ID: 100 µm, 外径: 165 µm, L: 7 厘米) 的尖端 (ca. 1 厘米)。</li>
		<li>将管子拧到聚醚醚酮 (PEEK) T 接合处的一个对立臂上, 用于1/16 英寸外径管, 安装在一个小金属桌上。现在, 毛细管应该突出一些 centemeters 出 T 连接。 注: 最好用管子切割机切割聚四氟乙烯管。对于毛细血管, 最好使用劈裂石。</li>
		<li>将合适的管件和套圈连接到第二聚四氟乙烯管的末端 (管 1.2;外径: 1/16 英寸, ID: 0.75 毫米), 足够长的时间到达水浴外的注射器泵, 并将其拧到 T 形接头的侧臂上。</li>
		<li>粘第三聚四氟乙烯管 (管 1.3;外径: 1/16 英寸, ID: 0.17 毫米) 通过其中一个隔膜。管1.3 应足够长, 以连接第二注射器泵与管1.1 内的水浴。分别在1.1 和1.3 管的备用端添加两个女性鲁尔锁, 用于1/16 英寸外径油管。</li>
		<li>准备第四聚四氟乙烯管 (聚合管 1.4;外径: 1/16 英寸, ID: 0.75 毫米), 配有合适的加箍, 并通过第二隔膜粘贴。管1.4 应该足够长的时间离开水浴和通过一个精密加热板。连接管 1.4通过其拟合到 T 形接头的剩余臂上, 并将玻璃毛细管的末端置于管内。</li>
		<li>将水浴放在装有温度计的热板上, 用胶带固定在精密加热板顶部的1.4 管, 并将5毫升玻璃瓶连接到管1.4 的末端。将管1.2 的末端连接到充满连续相的注射器 (硅油; 粘度: 1.000 米2/秒), 将管1.3 连接到装有液压油的注射器, 用于单体相 (硅油; 粘度: 100 米2/秒) 和插头注射器泵。 注: 为了将管子连接到注射器, 用3/32 英寸的 ID 管鲁尔的钩头到女性的锁连接器最好使用。</li>
		<li>安装一个显微镜, 其重点是在毛细管的尖端设置, 以使观察液滴形成和安装紫外线光源 (e. g, 500 W 汞蒸气灯) 与光锥聚焦在管1.4。</li>
	</ol>
</li>
	<li>
单体混合物的制备
	<ol>
<li>要准备单体混合物40, 添加200毫克 (4-acryloyloxybutyl)-25-二 (4-butyloxybenzoyloxy) 苯甲酸为50毫升梨形烧瓶。</li>
		<li>加入7.2 毫克的 16-hexanediol 甲基丙烯酸酯 (10 (摩尔)) 和6.2 毫克的乙基 (24, 6-trimethylbenzoyl) 苯膦酸 (光, 3 w%) 的烧瓶。将混合物溶解在大约1毫升的二氯甲烷中。 注意: 从步骤1.2.2 开始, 所有步骤都应在 UV 无光条件下执行 (例如, 在黄灯下)。</li>
		<li>将溶剂完全清除在真空下 313 k, 并在油浴中将剩余固体熔化 383 k。</li>
		<li>用3/32 英寸的 ID 油管和连接四氟管 (管 1.5) 的鲁尔锁连接器准备注射器;外径: 1/8 英寸, 编号: 1.65 毫米)通过连接管 (外径: 1/16 英寸, id: 0.75 毫米)。在注射器的帮助下, 将单体混合物绘制到管1.5 中。 注: 单体用量不应少于70毫克. 否则, 很难将足够的单体混合物绘制成管1.5。协议可以在这里暂停。如果是这样, 把管子放在冰箱里。</li>
	</ol>
</li>
	<li>
微粒的准备
	<ol>
<li>将男性鲁尔锁固定在1/8 英寸外径油管两端的管 1.5, 其中包含单体混合物。然后, 连接两端的管1.5 与女性鲁尔锁在1.1 和1.3 管的两端。 注: 在合成前应用注射器泵提供的液体冲洗管子。</li>
		<li>将水浴的温度设置为 363 k, 将精密加热板的温度设置为 338 k。</li>
		<li>确保毛细管的尖端是在聚合管的中心 1.5, 不接触墙壁。 注意: 这里给出的温度对这种单体混合物进行了优化。一般情况下, 水浴的温度应足够高, 以熔化单体混合物, 加热板的温度应在液晶相的温度范围内。</li>
		<li>在单体混合物融化后, 将连续相位 (Qc) 的流速设置为介于1.5 和2.0 毫升/小时之间的值, 并选择 qc/Qd (qd = 液压油/单体相的流速) 之间的流速比20和200。 注: 对于 qc = 1.75 毫升/小时和 qd = 0.35 毫升/小时的流速, 将观察到具有 d 270 µm 的良好驱动粒子。</li>
		<li>在液滴形成开始后, 等待, 直到水滴都是相同的大小, 然后再打开 UV 光。对于所描述的单体混合物, 将 UV 源的1厘米以上的聚合管1.4 在精密加热板的右端。收集5毫升玻璃瓶中聚合粒子的不同分数, 在1.4 管末端。在紫外光动时 , 水滴的颜色应该由透明变为白色。 注意: 佩戴防紫外线护目镜以保护眼睛。</li>
		<li>在光源和水浴之间放置一个盾牌 (例如,一个纸盒), 以防止毛细血管堵塞。 注: 如果一个堵塞的聚合管, 它可能有助于加热堵塞部分与热枪。</li>
		<li>在所有单体被消耗后, 通过将丙酮注入1.3 管来清洁安装。</li>
	</ol>
</li>
</ol>2. 核壳冰粒子的合成
<ol><li>
设备安装
	<ol>
<li>按照步骤1.1.1。但用190毫米的水浴盘代替。</li>
		<li>将管件和套圈连接到氟化乙烯丙烯 (FEP) 油管套筒的两端 (ID: 395 µm, 外径: 1/16 英寸, L: 1.55 英寸), 分别。首先, 粘附熔融二氧化硅毛细管 (ID: 280 µm, 外径: 360 µm, L: 8 厘米) 通过套筒, 在这样的方式, 它突出约3毫米出一侧。然后贴一个更薄的毛细管 (ID: 100 µm, OD: 165 µm, L:11 厘米) 通过较大的一个, 使它突出了几毫米的更长的一面。</li>
		<li>将套筒拧到1/16 英寸外径管 (T 型接头 1) 的 PEEK T 形接头的一个对立臂上, 它安装在一个小金属桌上, 而更短的毛细管端伸到 T 形接合处。</li>
		<li>贴一聚四氟乙烯管 (管 2.1;外径: 1/16 英寸, ID: 0.17 毫米), 这是足够长的连接注射器泵与 T 连接1通过一个水浴的隔膜。将管件和套圈连接到水浴内的管端, 将其与 T 连接1的自由侧臂相连, 并将较薄的毛细管插在管内2.1 内。</li>
		<li>准备第二聚四氟乙烯管 (管 2.2;外径: 1/16 英寸, ID: 0.5 毫米), 配有管件和套圈, 并将其连接到 T 型接线1的备用臂上。粘另一聚四氟乙烯管 (管 2.3;外径: 1/16 寸, ID: 0.5 毫米) 通过第二个孔在间隔在管子2.1 旁边。管2.3 应该足够长, 以连接另一个注射器泵与管2.2。</li>
		<li>将两个女性鲁尔锁分别添加到水浴内2.2 和2.3 管的自由端1/16 英寸外径油管上。</li>
		<li>将套筒的自由端连接到第二个 PEEK t 形连接线 (t 连接 2) 的另一臂上, 它也安装在小金属桌上。准备第四聚四氟乙烯管 (管 2.4;外径: 1/16 英寸, ID: 0.75 毫米), 配有管件加箍。管2.4 是足够长的时间到达第三个注射器泵外的水浴, 并连接到侧臂的 T 连接2。</li>
		<li>准备第五聚四氟乙烯管 (聚合管 2.5;外径: 1/16 英寸, ID: 0.75 毫米), 配有合适的加箍, 并通过其他隔膜粘贴。管2.5 应该足够长的时间离开水浴和通过一个高精度的加热板。将管2.5 的管件与 T 形接头的剩余臂连接。现在, 玻璃毛细血管的小贴士应该位于管2.5 内。</li>
		<li>将水浴放在装有温度计的热板上, 用胶带固定在精密加热板顶部的2.5 管, 并将5毫升玻璃瓶连接到管端。将管2.1 的末端连接到用甘油 (内相) 填充的注射器上, 将管2.3 连接至装有液压油的注射器, 用于单体相 (硅油; 粘度: 100 米2/秒), 连接管2.4 到用连续相填充的注射器 (硅油;粘度: 1.000 米2/秒), 并将所有注射器插入注射器泵中。</li>
		<li>按照步骤 1.1.7, 但读管2.5 而不是管1.4。</li>
	</ol>
</li>
	<li>
单体混合物的制备
	<ol>
<li>执行所有步骤1.2。</li>
	</ol>
</li>
	<li>
核壳颗粒的制备
	<ol>
<li>将1/8 英寸外径管的雄性鲁尔锁分别连接在包含单体混合物的管两端。之后, 连接这管两端的女性鲁尔锁在管的两端2.2 和2.3。</li>
		<li>按照步骤 1.3. 2-1. 3.4。</li>
		<li>观察液滴形成通过立体显微镜。</li>
	</ol>
</li>
</ol>3、双面冰颗粒的合成
<ol><li>
设备安装
	<ol>
<li>按照步骤1.1.1。</li>
		<li>将管件和套圈连接到 FEP 油管套筒的两端 (ID: 395 µm, 外径: 1/16 英寸, L: 1.55 英寸), 分别。粘接两个平行排列的熔融二氧化硅毛细管 (ID: 100 µm, 外径: 165 µm, l1: 8 厘米, l2:11 厘米) 通过套筒。短毛细管凸出约3毫米从一侧的袖子。在袖子的另一侧, 两个毛细血管的长度相同。</li>
		<li>将一些胶水粘在袖子的一端, 然后等到固化后再用胶水把毛细血管粘起来。</li>
		<li>将两个 PEEK 的 T 形连接, 分别拧紧在一个对立的手臂上, 并安装在一个小的金属表上。</li>
		<li>按照步骤 2.1. 4-2. 1.7。</li>
		<li>准备第五聚四氟乙烯管 (管 3.5;外径: 1/16 英寸, ID: 0.75 毫米, L: 5 厘米), 配有管件加插箍, 并将其与 T 形结2的剩余臂连接。玻璃毛细血管的两个小贴士位于管3.5 内。</li>
		<li>粘另一聚四氟乙烯管 (管 3.6;外径: 1/16 英寸, ID: 0.5 毫米) 通过其他隔膜。管2.6 应该足够长的时间离开水浴和通过一个精密加热板。连接管3.5 和 3.6通过管件系统的1/16 英寸 OD 油管。</li>
		<li>将水浴放在装有温度计的热板上, 用胶带固定在精密加热板顶部的3.6 管, 并将5毫升玻璃瓶连接到管端。将管3.1 的末端连接到充满水单体混合物的注射器 (蒽醌. 单体相), 将管3.3 连接至装有液压油的注射器, 用于 LC 单体相 (硅油; 粘度: 100 米2/秒), 将管3.4 连接至填充的注射器与连续相 (硅油; 粘度: 1.000 米2/秒), 并将所有注射器插入注射器泵中。</li>
		<li>跟随步骤 1.1.8, 但读管3.6 而不是管1.4。</li>
	</ol>
</li>
	<li>
液晶 (LC) 单体混合物的制备
	<ol>
<li>执行所有步骤1.2。</li>
	</ol>
</li>
	<li>
水中单体混合物的制备
	<ol>
<li>在蒸馏水中制备 40 wt% 丙烯酰胺溶液。添加 10 (摩尔) 的交联剂 n、n '-methylenebis (丙烯酰胺) 和 2 wt% 的引发剂 2-羟基 2-methylpropiophenone 到溶液中。(这两种量都是关于丙烯酰胺的。 注: 为了提高水中单体混合物的粘度, 可以添加聚丙烯酰胺。</li>
		<li>在 RT 中搅拌24小时的混合物, 然后将其填充到1毫升注射器中。</li>
	</ol>
</li>
	<li>
双面粒子的制备
	<ol>
<li>分别在包含 LC 单体混合物的管两端上附加一个雄性鲁尔锁, 用于1/8 英寸外径管。然后, 连接这管两端的女性鲁尔锁在3.2 和3.3 管的两端。</li>
		<li>按照步骤 1.3. 2-1. 3.4。</li>
		<li>观察液滴形成通过立体显微镜。</li>
	</ol>
</li>
</ol>4. 对微粒的分析
<ol><li>将粒子放在一个热级的光学显微镜下, 用成像软件连接到计算机上。为了分析粒子的驱动, 在温度高于和低于其相变温度的情况下拍照, 并测量它们的 D。 注: 一滴硅油可以防止微粒粘在物体的滑动上。</li>
	<li>为了估计粒子的清除温度, 确定粒子在偏振光学显微镜 (POM) 下失去双折射的温度。</li>
</ol>

<ol>
	<li>Ohm, C., Fleischmann, E. K., Kraus, I., Serra, C., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+the+properties+of+micrometer-sized+actuators+from+liquid+crystalline+elastomers+prepared+in+a+microfluidic+setup.">Control of the properties of micrometer-sized actuators from liquid crystalline elastomers prepared in a microfluidic setup.</a> Advanced Functional Materials. 20 (24), 4314-4322 (2010).</li><li>Urbanski, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+crystals+in+micron-scale+droplets,+shells+and+fibers.">Liquid crystals in micron-scale droplets, shells and fibers.</a> Journal of Physics: Condensed Matter. 29 (13), 133003 (2017).</li><li>Hessberger, T., Braun, L., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+actuating+microparticles+from+a+thiol-ene+based+main-chain+liquid+crystalline+elastomer.">Microfluidic synthesis of actuating microparticles from a thiol-ene based main-chain liquid crystalline elastomer.</a> Polymers (Basel). 8 (12), (2016).</li><li>Palagi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structured+light+enables+biomimetic+swimming+and+versatile+locomotion+of+photoresponsive+soft+microrobots.">Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots.</a> Nature Materials. , 1-8 (2016).</li><li>Ohm, C., Brehmer, M., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+crystalline+elastomers+as+actuators+and+sensors.">Liquid crystalline elastomers as actuators and sensors.</a> Advanced Materials. 22, 3366-3387 (2010).</li><li>White, T. J., Broer, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Programmable+and+adaptive+mechanics+with+liquid+crystal+polymer+networks+and+elastomers.">Programmable and adaptive mechanics with liquid crystal polymer networks and elastomers.</a> Nature Materials. 14 (11), 1087-1098 (2015).</li><li>Liu, D., Broer, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+crystal+polymer+networks:+preparation,+properties,+and+applications+of+films+with+patterned+molecular+alignment.">Liquid crystal polymer networks: preparation, properties, and applications of films with patterned molecular alignment.</a> Langmuir. 30 (45), 13499-13509 (2014).</li><li>Ube, T., Ikeda, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photomobile+polymer+materials+with+crosslinked+liquid-crystalline+structures:+molecular+design,+fabrication,+and+functions.">Photomobile polymer materials with crosslinked liquid-crystalline structures: molecular design, fabrication, and functions.</a> Angewandte Chemie International Edition in English. 53 (39), 10290-10299 (2014).</li><li>Zentel, R., Schmidt, G. F., Meyer, J., Benalia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+investigations+of+linear+and+cross-linked+liquid-crystalline+main+chain+and+combined+polymers.">X-ray investigations of linear and cross-linked liquid-crystalline main chain and combined polymers.</a> Liquid Crystals. 2 (5), 651-664 (1987).</li><li>Kapitza, H., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+liquid-crystalline+polymers+with+chiral+phases,+2+Lateral+substituents.">Combined liquid-crystalline polymers with chiral phases, 2 Lateral substituents.</a> Macromolecular Chemistry and Physics. 189, 1793 (1988).</li><li>Li, M. -. H., Keller, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Artificial+muscles+based+on+liquid+crystal+elastomers.">Artificial muscles based on liquid crystal elastomers.</a> Philosophical Transactions of the Royal Society A. Mathematical, Physical, and Engineering Sciences. 364 (1847), 2763-2777 (2006).</li><li>Wiesemann, A., Zentel, R., Pakula, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redox-active+liquid-crystalline+ionomers:+1.+Synthesis+and+rheology.">Redox-active liquid-crystalline ionomers: 1. Synthesis and rheology.</a> Polymer (Guildford). 33 (24), 5315-5320 (1992).</li><li>Pei, Z., Yang, Y., Chen, Q., Terentjev, E. M., Wei, Y., Ji, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouldable+liquid-crystalline+elastomer+actuators+with+exchangeable+covalent+bonds.">Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds.</a> Nature Materials. 13 (1), 36-41 (2014).</li><li>Wang, Z., Tian, H., He, Q., Cai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reprogrammable,+reprocessible,+and+self-healable+liquid+crystal+elastomer+with+exchangeable+disulfide+bonds.">Reprogrammable, reprocessible, and self-healable liquid crystal elastomer with exchangeable disulfide bonds.</a> ACS Applied Materials &amp; Interfaces. 9 (38), 33119-33128 (2017).</li><li>Chambers, M., Finkelmann, H., Rem&#353;kar, M., S&#225;nchez-Ferrer, A., Zalar, B., &#381;umer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+crystal+elastomer-nanoparticle+systems+for+actuation.">Liquid crystal elastomer-nanoparticle systems for actuation.</a> Journal of Materials Chemistry. 19 (11), 1524-1531 (2009).</li><li>Braun, L. B., Linder, T., Hessberger, T., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+a+crosslinker+containing+an+azo+group+on+the+actuation+properties+of+a+photoactuating+LCE+system.">Influence of a crosslinker containing an azo group on the actuation properties of a photoactuating LCE system.</a> Polymers.(Basel). 8 (12), 435 (2016).</li><li>Braun, L. B., Hessberger, T., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+micrometer-sized+photoresponsive+actuators+based+on+liquid+crystalline+elastomers.">Microfluidic synthesis of micrometer-sized photoresponsive actuators based on liquid crystalline elastomers.</a> Journal of Materials Chemistry C. 4, 8670-8678 (2016).</li><li>Ikeda, T., Mamiya, J. I., Yu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photomechanics+of+liquid-crystalline+elastomers+and+other+polymers.">Photomechanics of liquid-crystalline elastomers and other polymers.</a> Angewandte Chemie International Edition. 46, 506-528 (2007).</li><li>Zeng, H., Wani, O. M., Wasylczyk, P., Kaczmarek, R., Priimagi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-regulating+iris+based+on+light-actuated+liquid+crystal+elastomer.">Self-regulating iris based on light-actuated liquid crystal elastomer.</a> Advanced Materials. 29 (30), 1-7 (2017).</li><li>K&#252;pfer, J., Finkelrnann, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nematic+liquid+single+crystal+elastomers.">Nematic liquid single crystal elastomers.</a> Macromolecular Rapid Communications. 12, 717-726 (1991).</li><li>Bergmann, G. H. F., Finkelmann, H., Percec, V., Zhao, M. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid-crystalline+main-chain+elastomers.">Liquid-crystalline main-chain elastomers.</a> Macromolecular Rapid Communications. 18 (5), 353-360 (1997).</li><li>Li, M. H., Keller, P., Yang, J., Albouy, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+artificial+muscle+with+lamellar+structure+based+on+a+nematic+triblock+copolymer.">An artificial muscle with lamellar structure based on a nematic triblock copolymer.</a> Advanced Materials. 16 (21), 1922-1925 (2004).</li><li>Brehmer, M., Zentel, R., Wagenblast, G., Siemensmeyer, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ferroelectric+liquid-crystalline+elastomers.">Ferroelectric liquid-crystalline elastomers.</a> Macromolecular Chemistry and Physics. 195 (6), 1891-1904 (1994).</li><li>Beyer, P., Terentjev, E. M., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monodomain+liquid+crystal+main+chain+elastomers+by+photocrosslinking.">Monodomain liquid crystal main chain elastomers by photocrosslinking.</a> Macromolecular Rapid Communications. 28 (14), 1485-1490 (2007).</li><li>Ditter, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MEMS+analogous+micro-patterning+of+thermotropic+nematic+liquid+crystalline+elastomer+films+using+a+fluorinated+photoresist+and+a+hard+mask+process.">MEMS analogous micro-patterning of thermotropic nematic liquid crystalline elastomer films using a fluorinated photoresist and a hard mask process.</a> Journal of Materials Chemistry C. 5, 12635-12644 (2017).</li><li>Lopez-Valdeolivas, M., Liu, D., Broer, D. J., S&#225;nchez-Somolinos, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=4D+printed+actuators+with+soft-robotic+functions.">4D printed actuators with soft-robotic functions.</a> Macromolecular Rapid Communications. 1700710, 3-9 (2017).</li><li>Ohm, C., Kapernaum, N., Nonnenmacher, D., Giesselmann, F., Serra, C., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+highly+shape-anisotropic+particles+from+liquid+crystalline+elastomers+with+defined+director+field+configurations.">Microfluidic synthesis of highly shape-anisotropic particles from liquid crystalline elastomers with defined director field configurations.</a> Journal of the American Chemical Society. 133 (14), 5305-5311 (2011).</li><li>Ohm, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+actuating+fibres+of+oriented+main-chain+liquid+crystalline+elastomers+by+a+wetspinning+process.">Preparation of actuating fibres of oriented main-chain liquid crystalline elastomers by a wetspinning process.</a> Soft Matter. 7, 3730 (2011).</li><li>Hessberger, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Co-flow+microfluidic+synthesis+of+liquid+crystalline+actuating+Janus+particles.">Co-flow microfluidic synthesis of liquid crystalline actuating Janus particles.</a> Journal of Materials Chemistry C. 4, 8778-8786 (2016).</li><li>Fleischmann, E. -. K., Liang, H. -. L., Kapernaum, N., Giesselmann, F., Lagerwall, J., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-piece+micropumps+from+liquid+crystalline+core-shell+particles.">One-piece micropumps from liquid crystalline core-shell particles.</a> Nature Communications. 3, 1178 (2012).</li><li>Khan, I. U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+conceived+drug+loaded+Janus+particles+in+side-by-side+capillaries+device.">Microfluidic conceived drug loaded Janus particles in side-by-side capillaries device.</a> International Journal of Pharmaceutics. 473 (1-2), 239-249 (2014).</li><li>Vennes, M., Martin, S., Gisler, T., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anisotropic+particles+from+LC+polymers+for+optical+manipulation.">Anisotropic particles from LC polymers for optical manipulation.</a> Macromolecules. 39 (24), 8326-8333 (2006).</li><li>Serra, C. a., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+polymer+microparticles+by+droplet+microfluidics.">Engineering polymer microparticles by droplet microfluidics.</a> Journal of Flow Chemistry. 3 (3), 66-75 (2013).</li><li>Seo, M., Nie, Z., Xu, S., Lewis, P. C., Kumacheva, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidics:+from+dynamic+lattices+to+periodic+arrays+of+polymer+disks.">Microfluidics: from dynamic lattices to periodic arrays of polymer disks.</a> Langmuir. 21 (11), 4773-4775 (2005).</li><li>Kim, K., Pack, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microspheres+for+drug+delivery.">Microspheres for drug delivery.</a> BioMEMS and Biomedical Nanotechnology. 2, 19-50 (2006).</li><li>Kim, J. -. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Titanium+dioxide/poly(methyl+methacrylate)+composite+microspheres+prepared+by+in+situ+suspension+polymerization+and+their+ability+to+protect+against+UV+rays.">Titanium dioxide/poly(methyl methacrylate) composite microspheres prepared by in situ suspension polymerization and their ability to protect against UV rays.</a> Colloid and Polymer Science. 280 (6), 584-588 (2002).</li><li>Serra, C., Berton, N., Bouquey, M., Prat, L., Hadziioannou, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+predictive+approach+of+the+influence+of+the+operating+parameters+on+the+size+of+polymer+particles+synthesized+in+a+simplified+microfluidic+system.">A predictive approach of the influence of the operating parameters on the size of polymer particles synthesized in a simplified microfluidic system.</a> Langmuir. 23 (14), 7745-7750 (2007).</li><li>Chang, Z., Serra, C. a., Bouquey, M., Prat, L., Hadziioannou, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Co-axial+capillaries+microfluidic+device+for+synthesizing+size-+and+morphology-controlled+polymer+core-polymer+shell+particles.">Co-axial capillaries microfluidic device for synthesizing size- and morphology-controlled polymer core-polymer shell particles.</a> Lab on a Chip. 9, 3007-3011 (2009).</li><li>Braun, L. B., Hessberger, T., Serra, C. A., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UV-free+microfluidic+particle+fabrication+at+low+temperature+using+ARGET-ATRP+as+the+initiator+system.">UV-free microfluidic particle fabrication at low temperature using ARGET-ATRP as the initiator system.</a> Macromolecular Reaction Engineering. 10 (6), 611-617 (2016).</li><li>Thomsen, D. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+crystal+elastomers+with+mechanical+properties+of+a+muscle.">Liquid crystal elastomers with mechanical properties of a muscle.</a> Macromolecules. 34, 5868-5875 (2001).</li><li>Ohm, C., Serra, C., Zentel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+continuous+flow+synthesis+of+micrometer-sized+actuators+from+liquid+crystalline+elastomers.">A continuous flow synthesis of micrometer-sized actuators from liquid crystalline elastomers.</a> Advanced Materials. 21 (47), 4859-4862 (2009).</li></ol>

作者没有什么可透露的。

我们描述了不同形貌的粒子的制造,通过微流控方法生产冰微执行器。为此, 建立了毛细管微流控装置, 允许液滴形成, 然后在规定的温度下聚合。
在这里, 成功合成的一个关键方面是安装的正确安装。必须正确修复单个部件之间的所有连接, 以防止液体泄漏, 并且在每次合成前必须清洁设备以防止堵塞。同样重要的是, 实验是在无紫外线条件下进行的, 因为, 否则, 单体混合物过早聚合, 从而再次堵塞的设置将是结果。
到今天, 这里描述的微流控方法是唯一能够产生驱动的冰粒子的方法。在此, 微流控过程同时满足两个要求。除了制造大量的同样大小的微型物体, 液晶控制器的方向在这些粒子中被诱导。此外, 这是一个相当简单的程序, 因为大量的执行器可以合成一个单一的步骤。应用其他方法, 液晶聚的方向通常需要一个额外的步骤, 如拉伸的样本或应用的照片对准层。此外, 这些过程是手动的, 这意味着许多执行器的生产是非常耗时的。此外, 冰形态是-在大多数情况下, 仅限于聚合物薄膜。微流控方法的缺点是颗粒尺寸的限制 (因为直径限制在200和400µm 之间的值), 堵塞毛细管的脆弱性, 以及在粒子制备过程中无紫外线条件的必要性。安装程序。
芯片上的系统经常被用于微流控粒子的制造, 因为它们可以很容易地产生, 只由一个片断组成。然而, 这些设置, 不仅缺乏必要的调节, 在流动的不同温度, 但也不够灵活, 以方便地交换堵塞或损坏的部分微反应器。因此, 我们使用的毛细管型设置更适合于冰执行器的合成, 因为它们满足了关键的要求。
除了我们所提出的驱动微型泵粒子和核壳的结果, 更复杂的驱动粒子具有新的性能, 可以在未来合成, 并打开新的可能性, 软执行器的应用。在对多响应粒子进行进一步的修饰时, 已经在进行中。因此, 我们的目标是引进第二温度反应聚合物除了驱动冰。进一步可能性为新的微粒设计也可能出现从使用液晶偶氮单体, 导致冰微粒的轻驱动的驱动力17,18。在这种情况下, 我们可以想到的是既包含温度响应, 也包括光驱动部分的两面粒子。光驱动的核壳颗粒或类似管道结构的合成提供了另一种可能的粒子设计, 这将导致光响应微型泵。我们上面提出的微流控原理的修正应该允许各种新的执行器。

微流控合成已成为最近几年制造液晶弹性体 (冰) 驱动器的著名方法1,2,3。这种方法不仅使生产大量的良好的驱动粒子, 而且还允许制造的形状和形貌, 这是不可用的其他方法。因为在微型机器人中, 冰执行器是一个应用人造肌肉的候选者, 所以合成这种粒子的新方法对于未来的技术4是非常重要的。
在 LCEs 中, 液晶 (LC) 的液晶聚连接到弹性体网络的聚合物链 5, 6, 7, 8.液晶聚与聚合物链的联系可以以侧链、主链或联合 LC 聚合物9、10、11的形式出现.交联点之间的距离应该足够远, 允许在中间的聚合物链的自由重新定向 (事实上, 这是真实的任何弹性体, 区分他们从 "热固性")。因此, 交联可以是永久性的或可逆的, 因为强的非共价键相互作用12,13,14。这种材料结合了两种特性, 即液晶的各向异性行为与弹性体的熵弹性。在液晶相的温度范围内, 聚合物链采用了由液晶相的各向异性引起的 (或多或少) 拉伸构象, 这是由向列序参量量化的。当样品被带到正向向各向同性相变温度以上时, 各向异性消失, 网络松弛到大力偏爱的随机线圈构象。这导致一个宏观变形, 从而驱动5,15。除了加热的样品, 这种相变也可能诱发其他刺激, 如光或溶剂扩散在 LCEs16,17,18,19。
为了获得强烈的变形, 在交联步骤20期间, 样本必须形成一个 monodomain 或特征至少是单个域控制器的首选方向。对于冰膜的生产, 这通常是通过拉伸预聚合样品,通过在电场或磁场中的域方向, 借助照片对齐层或通过3 d 打印21 ,22,23,24,25,26。
另一种方法是用毛细管微流控液滴发生器连续制备冰微粒。液晶单体水滴分散在高度粘性的连续相, 流动在水滴周围, 并在水滴表面应用剪切速率。因此, 在单体液滴内循环观察, 导致液晶相的整体对准27。因此, 在水滴上作用的剪切速率的大小对液滴的形状和大小, 以及液晶控制器的方向有很大的影响。这些良好的液滴可以在微流控装置的下游进一步聚合。因此, 使用不同形状 (例如、粒子和纤维) 和更复杂的形貌 (如核壳和双面粒子) 的驱动器的制备是可能的28,29,30,31。它甚至可以制备扁颗粒, 沿其对称轴和高度扁, 纤维状粒子, 在相变收缩。这两种粒子都可以用同一种微流控装置进行, 只需改变剪切速率27。在此, 我们提出了如何在自制毛细管微流控装置上生产不同形貌的冰执行器的协议。
除了基团对冰液的影响, 以及不同形状的聚合物的可达性, 微流控方法还有进一步的优势。比其他微粒制造方法象降雨雪在非溶剂或悬浮聚合32 (导致微粒以宽广的大小分布), 单分散微粒 (微粒大小的变动系数是 < 5%) 可以使用微流体 33, 34 来合成.另外, 通过流动可以很容易地打破水滴的球体对称性。因此, 具有圆柱对称性的大粒子是可访问的, 这是执行器所需要的。这与悬浮聚合32所做的 LC 粒子不同。此外, 粒子的大小是很好的可调的微流体在一个范围从几微米到上百个微米, 和添加剂可以很容易地被带入颗粒或在其表面。这就是为什么微流控微粒制剂经常用于诸如药物传递35或化妆品36的制造等主题。
本文中使用的微流控装置由塞拉et介绍。33,37,38.这些都是自制的, 由高效液相色谱 (HPLC) 聚四氟乙烯 (PTFE) 管和 T 连接, 以及提供单相的熔融二氧化硅毛细血管组成。因此, 设置可以很容易地修改, 单件可以简单地交换, 因为它们是商业可用。在单体混合物中加入一个光, 使适当的光源能够在它们离开毛细管后, 在飞行中诱导液滴的聚合。除毛细血管外的照射是必要的, 以防止堵塞的设置。其他类型的聚合仅在液滴离开毛细管 (例如, 与基于氧化还原过程的启动器)39之后才开始聚合。然而, 由于光诱导交联聚合的速度和远程控制能力, 引发是最有利的一种。
由于冰的单体混合物在室温下是结晶的, 因此需要对整个微流控装置进行仔细的温度控制。因此, 产生液滴形成的部分设置放在水浴中。在这里, 水滴是在高温下形成的混合物的各向同性熔融。对于定向, 水滴必须冷却成液晶相。因此, 聚合管放置在热板上, 设置为 LC 阶段的较低温度范围 (图 1)。
在这里, 我们描述了一个灵活和直接的方法, 制造的冰执行器在一个流动。该协议提供了在几分钟内为合成单个粒子以及双面和核壳粒子建立微流控装置所需的步骤。接下来, 我们描述了如何运行一个综合, 并显示了典型的结果, 以及驱动粒子的性质。最后, 我们讨论了这种方法的优点, 以及为什么我们认为它可能会给冰执行器领域带来进展。

<table border="0" cellpadding="0" cellspacing="0" style="width:877px;" width="877">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">NanoTight fitting for 1/16&#39;&#39; OD tubings</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">F-333N</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">NanoTight ferrule for 1/16&#39;&#39; OD tubings</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">F-142N</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">PEEK Tee for 1/16&#8221; OD Tubing</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">P-728</td>
			<td>T-junction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Female Fitting for 1/16&#8221; OD Tubing</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">P-835</td>
			<td>female luer-lock</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Male Fitting for 1/8&#8221; OD Tubing</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">P-831</td>
			<td>male luer-lock</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:363px;">Female Luer Connectors for use with 3/32&#8221; ID tubings</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">P-858</td>
			<td>for the syrringe&#39;s tip</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">NanoTight FEP tubing sleeve ID: 395 &#181;m OD: 1/16&#39;&#39;</td>
			<td style="width:220px;">Postnova_IDEX</td>
			<td style="width:128px;">F-185</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Fused Silica Capillary Tubing ID: 100 &#181;m OD: 165 &#181;m</td>
			<td style="width:220px;">Postnova</td>
			<td style="width:128px;">Z-FSS-100165</td>
			<td>glass capillary</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Fused Silica Capillary Tubing ID: 280 &#181;m OD: 360 &#181;m</td>
			<td style="width:220px;">Postnova</td>
			<td style="width:128px;">Z-FSS-280360</td>
			<td>glass capillary</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">&#8216;&#8216;Pump 33&#8217;&#8217; DDS</td>
			<td style="width:220px;">Harvard Apparatus</td>
			<td>70-3333</td>
			<td>syringe pump</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Precision hot plate</td>
			<td style="width:220px;">Harry Gestigkeit GmbH</td>
			<td style="width:128px;">PZ 28-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Stereomicroscope stemi 2000-C</td>
			<td style="width:220px;">Carl Zeiss Microscopy GmbH</td>
			<td style="width:128px;">455106-9010-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Mercury vapor lamp Oriel LSH302</td>
			<td style="width:220px;">LOT</td>
			<td style="width:128px;"></td>
			<td>Intensity: 500 W</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Teflon Kapillare, 1/16&#39;&#39; x 0,75mm</td>
			<td style="width:220px;">WICOM</td>
			<td style="width:128px;">WIC 33104</td>
			<td>teflon tube</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Teflon Kapillare, 1/16&#39;&#39; x 0,50mm</td>
			<td style="width:220px;">WICOM</td>
			<td style="width:128px;">WIC 33102</td>
			<td>teflon tube</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Teflon Kapillare, 1/16&#39;&#39; x 0,17mm</td>
			<td style="width:220px;">WICOM</td>
			<td style="width:128px;">WIC 33101</td>
			<td>teflon tube</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Silicion oil 1.000 cSt</td>
			<td style="width:220px;">Sigma Aldrich</td>
			<td align="right">378399</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Silicion oil 100 cSt</td>
			<td style="width:220px;">Sigma Aldrich</td>
			<td align="right" style="width:128px;">378364</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">1,6-hexanediol dimethacrylate</td>
			<td style="width:220px;">Sigma Aldrich</td>
			<td align="right" style="width:128px;">246816</td>
			<td>Crosslinker</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Lucirin TPO</td>
			<td style="width:220px;">Sigma Aldrich</td>
			<td align="right" style="width:128px;">415952</td>
			<td>Initiator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Polarized optical microscope BX51</td>
			<td style="width:220px;">Olympus</td>
			<td style="width:128px;"></td>
			<td>For analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Hotstage TMS 94</td>
			<td style="width:220px;">Linkam</td>
			<td style="width:128px;"></td>
			<td>For analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">Imaging software Cell^D</td>
			<td style="width:220px;">Olympus</td>
			<td style="width:128px;"></td>
			<td>For analysis</td>
		</tr>
	</tbody>
</table>

microfluidic preparation of liquid crystalline elastomer actuators

本文重点研究了微流控过程 (及其参数), 从液晶弹性体中制备驱动粒子。制备通常包括在高温下形成含有低摩尔质量液晶的水滴。随后, 这些粒子前体在毛细管的流场中定向, 通过交联聚合固化, 产生最终的驱动粒子。该工艺的优化是为了获得驱动粒子和工艺参数 (温度和流速) 的适当变化, 并允许大小和形状的变化 (从扁球形到强扁形貌), 以及驱动的大小。此外, 也有可能改变驱动从伸长到收缩的类型, 这取决于在毛细管中流体中诱导的液滴的导演剖面, 这又取决于微流控过程及其参数。此外, 还可以通过调整设置来制备更复杂形状的粒子, 如核壳结构或双面粒子。通过液晶弹性体的化学结构和交联 (凝固) 方式的变化, 也可以制备由热或紫外辐照引发的驱动粒子。

在本协议中, 我们提出了用微流控法对不同形貌的冰粒子进行合成的方法 (通过)。用于制造单核壳和双面粒子的微流控装置, 如图 129、38、41所示。连续流动生产的一个好处是对微粒的大小和形状的非常好控制。图 2a说明了单滴设置的优点: 一个非常窄的大小分布, 所有粒子具有相同的形状41。因此, 通过改变不同相的流速比, 可以很容易地调整球体的大小。按照该协议, 在200和400µm 之间的粒子直径可以通过选择流量比率来进行控制, 如图 2b1所示。对于1.5 至2.0 毫升/小时之间的连续相位 (Qc) 的流速和 qc/Qd (qd = 单体相的流速) 在20和200之间的流速比率, 获得最佳结果。例如, 对于 qc = 1.75 毫升/小时和 qd = 0.35 毫升/小时的流速, 有270µm 直径的良好驱动粒子被观察到。如果选择较高的比值 Qc/Qd , 则雾滴的形成受到较少的控制, 颗粒的尺寸分布变得更加广阔。对于较低的比值, 粒子不再是球形的。除流量调整外, UV 灯与聚合管的距离以及精密热板的左、右端之间的位置可以改变冰粒的驱动特性, 如聚合动力学变化的原因选择单体混合物的成分或应用聚合温度不同于这里描述的价值。
图 3a显示在加热超过其相变温度时拉长70% 的驱动粒子, 这证明了在聚合之前诱导液晶控制器定向的要求。液晶聚的这种对准是由于高粘性连续相和单体水滴表面之间的剪切而产生的。如果使用较低粘度的硅油, 则减少了粒子的驱动。
此外, 微流控装置允许对不同类型的驱动模式进行控制, 例如在相变过程中的伸长或收缩, 通过改变聚合过程中水滴作用的剪切速率。采用不同的聚合管内径, 可以很容易地在连续相的恒定流速下处理。图 3a显示一个扁形状的粒子, 它沿其旋转轴拉长, 在更宽的聚合管中以较低的剪切速率合成 (ID: 0.75 毫米)。在这种情况下, 液晶分子 (液晶聚) 沿同心控制器场对齐。在另一侧, 杆状粒子 (如图 3b中所示) 的特点是在相变过程中收缩, 液晶聚 "控制器" 字段的双极对准。该粒子是在更薄的聚合管中以较高的剪切速率产生的 (ID: 0.5 毫米)。
该协议描述了微流控过程的另一个优点。除单一粒子外, 还可以合成更复杂形貌的样品。图 3c显示一个驱动内核 shell 粒子和图 3d , 这两个粒子都是在协议29、30的2和3部分之后产生的。
如果协议的所有步骤都正确完成, 则应获得图 4中显示的属性的粒子341。在图 4a中, 绘制了在不同流速下合成的单个粒子的加热和冷却曲线。通过加热粒子的室温, 液晶的顺序是-在第一次减少一点点, 导致小变形的粒子。然而, 接近相变温度, 所有方向突然消失, 粒子显示一个强大的伸长只是通过加热它的几个程度。通过冷却颗粒向下, 可以观察到滞后现象, 并获得原始形状。此过程在许多驱动周期中是可逆的, 如图 4b所示。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57715/57715fig1.jpg"> 图 1: 微流控设置.(a) 一般设置包括三注射器, 其中包含液压硅油 (1)、水单体混合物 (3) 和连续相硅油 (4)。液晶单体混合物 (2) 放在水浴 (5) 在 363 K, 加热液晶到各向同性状态。该液滴的聚合是在热板 (6) 上开始的, 在 338 K 的液晶的向列状态的紫外线照射 (7)。(单一粒子设置等于一般设置, 但缺少第二毛细管, 注射器 (3) 和第二 T 连接)。(b) 此面板显示一个安装程序, 其中包含两个毛细血管并排, 从而允许双面熔滴形成。(c) 核心外壳设置由毛细管组成, 缩短为更宽的第二毛细管。<a href="/files/ftp_upload/57715/57715fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57715/57715fig2.jpg"> 图 2:微流控单粒子设置中获得的代表性粒子。(a) 此面板显示了微流控单粒子设置中制备的分散的冰粒子的显微图像。刻度条 = 200 µm. (b) 此面板显示了粒子直径与油的流速 (qc) 与单体混合物的流速 (qd) 的比值的依赖性。得到的粒子的大小只取决于两个阶段的速度比, 而不是它们的绝对值。(此数字已从欧姆、弗莱希曼天文、克劳斯、塞拉和 Zentel 1 和欧姆、塞拉和 Zentel 41 中进行了修改. <a href="/files/ftp_upload/57715/57715fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57715/57715fig3.jpg"> 图 3: 四种不同粒子形貌的光学显微图像 (在 353 k) 和在各向同性状态下的相变 (413 k)。这些面板显示 (a) 一个扁形的冰粒子 (同心控制器场) 的伸长, (b) 一个棒状的冰-粒子 (双极控制器场) 的收缩, (c) 扁形核壳的伸长率粒子和 (d) 收缩的扁形的双面粒子 (左部分: 冰, 右部分: 丙烯酰胺水凝胶)。刻度条 = 100 µm.<a href="/files/ftp_upload/57715/57715fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57715/57715fig4.jpg"> 图 4: 具有代表性的单个粒子的驱动属性。(a) 此面板显示了在连续相的不同流速下, 在单粒子微流控装置中制备的冰粒子的加热和冷却曲线。在最高流速下制备的粒子表现出最强的驱动 (约 70%), 两条曲线分别形成迟滞。(b) 这是一个图10个驱动循环的冰粒子显示没有减少其驱动的周期数。这证明了粒子是交联的, 驱动是完全可逆的。注: 此图是为一个由主链冰系统制成的粒子绘制的, 但与本文使用的冰系统看起来是一样的。(此数字已从欧姆、塞拉和 Zentel41中进行了修改。<a href="/files/ftp_upload/57715/57715fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Microfluidic Preparation of Liquid Crystalline Elastomer Actuators at JoVE.com

Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

液晶弹性体致动器的微流控制备

本文介绍了微流控工艺和参数, 以准备从液晶弹性体的驱动粒子。这一过程允许制备的驱动粒子和其大小和形状的变化 (从扁球形到强扁, 核壳, 和双面形貌) 以及驱动的大小。

This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation ...

microfluidic-preparation-of-liquid-crystalline-elastomer-actuators

Nanyang Technological University

Research

JoVE Journal

Chemistry

8.9K 次观看.  Johannes Gutenberg University. 本文介绍了微流控工艺和参数, 以准备从液晶弹性体的驱动粒子。这一过程允许制备的驱动粒子和其大小和形状的变化 (从扁球形到强扁, 核壳, 和双面形貌) 以及驱动的大小。

视频: Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the face of turgor pressures several atmospheres in magnitude. Across the diverse shapes and sizes of the bacterial kingdom, the cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by short peptides. Peptidoglycan&#8217;s central importance to bacterial physiology underlies its use as an antibiotic target and has motivated genetic, structural, and cell biological studies of how it is robustly assembled during growth and division. Nonetheless, extensive investigations are still required to fully characterize the key enzymatic activities in peptidoglycan synthesis and the chemical composition of bacterial cell walls. High Performance Liquid Chromatography (HPLC) is a powerful analytical method for quantifying differences in the chemical composition of the walls of bacteria grown under a variety of environmental and genetic conditions, but its throughput is often limited. Here, we present a straightforward procedure for the isolation and preparation of bacterial cell walls for biological analyses of peptidoglycan via HPLC and Ultra Performance Liquid Chromatography (UPLC), an extension of HPLC that utilizes pumps to deliver ultra-high pressures of up to 15,000 psi, compared with 6,000 psi for HPLC. In combination with the preparation of bacterial cell walls presented here, the low-volume sample injectors, detectors with high sampling rates, smaller sample volumes, and shorter run times of UPLC will enable high resolution and throughput for novel discoveries of peptidoglycan composition and fundamental bacterial cell biology in most biological laboratories with access to an ultracentrifuge and UPLC.

The bacterial cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by peptides. Ultra Performance Liquid Chromatography provides high resolution and throughput for novel discoveries of peptidoglycan composition. We present a procedure for the isolation of cell walls (sacculi) and their subsequent preparation for analysis via UPLC.

通过超性能液相色谱对细菌细胞壁进行隔离和制备，进行组成分析

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the ...

科研

化学

Manufacturing of Three-dimensionally Microstructured Nanocomposites through Microfluidic Infiltration

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite in&#64257;ltration of 3D interconnected microfluidic networks. The manufacturing of the reinforced beams begins with the fabrication of microfluidic networks, which involves layer-by-layer deposition of fugitive ink filaments using a dispensing robot, filling the empty space between filaments using a low viscosity resin, curing the resin and finally removing the ink.&#160;Self-supported 3D structures with other geometries and many layers (e.g.&#160;a few hundreds layers) could be built using this method. The resulting tubular micro&#64258;uidic networks are then infiltrated with thermosetting nanocomposite suspensions containing nanofillers (e.g.&#160;single-walled carbon nanotubes), and subsequently cured. The infiltration is done by applying a pressure gradient between two ends of the empty network (either by applying a vacuum or vacuum-assisted microinjection). Prior to the infiltration, the nanocomposite suspensions are prepared by dispersing nanofillers into polymer matrices using ultrasonication and three-roll mixing methods. The nanocomposites (i.e.&#160;materials infiltrated) are then solidified under UV exposure/heat cure, resulting in a 3D-reinforced composite structure. The technique presented here enables the design of functional nanocomposite macroscopic products for microengineering applications such as actuators and sensors.

Three-dimensional (3D) microstructured composite beams are fabricated through the directed and localized infiltration of nanocomposites into 3D porous microfluidic networks. The flexibility of this manufacturing method enables the utilization of different thermosetting materials and nanofillers in order to achieve a variety of functional 3D reinforced nanocomposite macroscopic products.

通过微流体渗透制备三维微结构纳米复合材料的制造

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

合成与盘状磷酸盐锆剥落获取胶体液晶

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

A novel methodology is presented to synthesize and program main-chain liquid-crystalline elastomers using commercially available starting monomers. A wide range of thermomechanical properties was tailored by adjusting the amount of crosslinker, while the actuation performance was dependent on the amount of applied strain during programming.

的可编程主链液晶性弹性体用双级硫醇丙烯酸酯反应合成

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline ...

CN-GELFrEE - Clear Native Gel-eluted Liquid Fraction Entrapment Electrophoresis

Protein complexes perform an array of crucial cellular functions. Elucidating their non-covalent interactions and dynamics is paramount for understanding the role of complexes in biological systems. While the direct characterization of biomolecular assemblies has become increasingly important in recent years, native fractionation techniques that are compatible with downstream analysis techniques, including mass spectrometry, are necessary to further expand these studies. Nevertheless, the field lacks a high-throughput, wide-range, high-recovery separation method for native protein assemblies. Here, we present clear native gel-eluted liquid fraction entrapment electrophoresis (CN-GELFrEE), which is a novel separation modality for non-covalent protein assemblies. CN-GELFrEE separation performance was demonstrated by fractionating complexes extracted from mouse heart. Fractions were collected over 2 hr and displayed discrete bands ranging from ~30 to 500 kDa. A consistent pattern of increasing molecular weight bandwidths was observed, each ranging ~100 kDa. Further, subsequent reanalysis of native fractions via SDS-PAGE showed molecular-weight shifts consistent with the denaturation of protein complexes. Therefore, CN-GELFrEE was proved to offer the ability to perform high-resolution and high-recovery native separations on protein complexes from a large molecular weight range, providing fractions that are compatible with downstream protein analyses.

This protocol describes how to prepare and perform clear native gel-eluted liquid fraction entrapment electrophoresis (CN-GELFrEE), a native separation technique for non-covalent biomolecular assemblies and proteins from heterogeneous samples that is compatible with various downstream protein analysis techniques.

CN-GELFrEE  - 透明天然凝胶洗脱液体馏分偷天陷阱电泳

Protein complexes perform an array of crucial cellular functions. Elucidating their non-covalent interactions and dynamics is paramount for understanding ...

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface (SALVI) and Scanning Electron Microscopy (SEM). This paper describes the method and key steps in integrating the vacuum compatible SAVLI to SEM and obtaining secondary electron (SE) images of particles in liquid in high vacuum. Energy dispersive x-ray spectroscopy (EDX) is used to obtain elemental analysis of particles in liquid and control samples including deionized (DI) water only and an empty channel as well. Synthesized boehmite (AlOOH) particles suspended in liquid are used as a model in the liquid SEM illustration. The results demonstrate that the particles can be imaged in the SE mode with good resolution (i.e., 400 nm). The AlOOH EDX spectrum shows significant signal from the aluminum (Al) when compared with the DI water and the empty channel control. In situ liquid SEM is a powerful technique to study particles in liquid with many exciting applications. This procedure aims to provide technical know-how in order to conduct liquid SEM imaging and EDX analysis using SALVI and to reduce potential pitfalls when using this approach.

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM

We present a procedure for real-time imaging and elemental composition analysis of boehmite particles in deionized water by in situ liquid Scanning Electron Microscopy.

原位水中石粒子的液体扫描电镜表征

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables the silk proteins to be compact and ordered by shearing and elongation forces. Here, a biomimetic microfluidic channel was designed to mimic the specific geometry of the spinning duct of the silkworm. Regenerated silk fibroin (RSF) spinning doped with high concentration, was extruded through the microchannel to dry-spin fibers at ambient temperature and pressure. In the post-treated process, the as-spun fibers were drawn and stored in ethanol aqueous solution. Synchrotron radiation wide-angle X-ray diffraction (SR-WAXD) technology was used to investigate the microstructure of single RSF fibers, which were fixed to a sample holder with the RSF fiber axis normal to the microbeam of the X-ray. The crystallinity, crystallite size, and crystalline orientation of the fiber were calculated from the WAXD data. The diffraction arcs near the equator of the two-dimensional WAXD pattern indicate that the post-treated RSF fiber has a high orientation degree.

A protocol for the microfluidic spinning and microstructure characterization of regenerated silk fibroin monofilament is presented.

微流控干纺及再生丝素纤维的表征

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully understood. We have traced the trajectories of individual nanoparticles using liquid-cell transmission electron microscopy (TEM) to investigate the mechanism of the assembly process. Herein, we present the protocols used for liquid-cell TEM studies of the self-assembly mechanism. First, we introduce the detailed synthetic protocols used to produce uniformly sized platinum and lead selenide nanoparticles. Next, we present the microfabrication processes used to produce liquid cells with silicon nitride or silicon windows and then describe the loading and imaging procedures of the liquid-cell TEM technique. Several notes are included to provide helpful tips for the entire process, including how to manage the fragile cell windows. The individual motions of nanoparticles tracked by liquid-cell TEM revealed that changes in the solvent boundaries caused by evaporation affected the self-assembly process of nanoparticles. The solvent boundaries drove nanoparticles to primarily form amorphous aggregates, followed by flattening of the aggregates to produce a 2-dimensional (2D) self-assembled structure. These behaviors are also observed for different nanoparticle types and different liquid-cell compositions.

Here we introduce experimental protocols for the real-time observation of a self-assembly process using liquid-cell transmission electron microscopy.

用于跟踪纳米粒子自组装的液体细胞透射电子显微镜

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully ...

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

观测 Photoresponsive 液晶结构动力学的新方法

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation

We demonstrate a method for fabricating a prototype reflective display device that contains cholesteric liquid crystal (LC) as an active component. The cholesteric LC is composed of a nematic LC 4&#39;-pentyloxy-4-cyanobiphenyl (5OCB), redox-responsive chiral dopant (FcD), and a supporting electrolyte 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIm-OTf). The most important component is FcD. This molecule changes its helical twisting power (HTP) value in response to redox reactions. Therefore, in situ electrochemical redox reactions in the LC mixture allow for the device to change its reflection color in response to electrical stimuli. The LC mixture was introduced, by a capillary action, into a sandwich-type ITO glass cell comprising two glass slides with patterned indium tin oxide (ITO) electrodes, one of which was coated with poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) doped with perchlorate (PEDOT+). Upon application of +1.5 V, the reflection color of the device changed from blue (467 nm) to green (485 nm) in 0.4 s. Subsequent application of 0 V made the device recover the original blue color in 2.7 s. This device is characterized by its fastest electrical response and lowest operating voltage among any previously reported cholesteric LC device. This device could pave the way for the development of next generation reflective displays with low energy consumption rates.

A protocol for the fabrication of a reflective cholesteric liquid crystalline display device containing a redox-responsive chiral dopant allowing quick and low-voltage operation is presented.

一种用于快速和低压彩色调制的电化学胆固醇液晶器件

We demonstrate a method for fabricating a prototype reflective display device that contains cholesteric liquid crystal (LC) as an active component. The ...