Influence of PEG on the clustering of active Janus colloids
Influence of PEG on the clustering of active Janus colloids
复制标题
PEG对活性Janus胶体团聚的影响
DOI：
10.1016/j.colsurfa.2021.127191
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Wirth, Christopher L.
中科院分区：
文献类型：
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作者：
Kalil, Mohammed A.;Baumgartner, Nicky R.;Issa, Marola W.;Ryan, Shawn D.;Wirth, Christopher L.
微米尺度的“胶体”粒子以一种确定性的方式推进，以响应当地的环境线索，是自然界中发现的自我推进实体的有用类似物。无论是天然的还是合成的活性胶体系统，都经常靠近边界或位于拥挤的环境中。在这里，我们描述了实验，我们测量了过氧化氢浓度和分散的聚乙二醇（PEG）对5µm催化活性Janus颗粒在低浓度下聚类行为的影响。我们发现，在没有PEG的情况下，随着过氧化氢浓度的增加，活性Janus颗粒聚集的程度增加。一旦加入PEG，聚类在低PEG体积分数下略有增强，但在高PEG体积分数下则有所减弱。聚类在较高PEG体积分数下被缓解的区域对应于先前发现推进被淬灭的区域。基于互补代理的仿真表明，聚类以名义速度增长。这些数据支持了一个假设，即随着推进速度的增加，活晶体的生长得到了增强，但在这些条件下，由于推进速度的淬灭，PEG的加入往往会减轻簇的形成。
Micrometer scale “colloidal” particles that propel in a deterministic fashion in response to local environmental cues are useful analogs to self-propelling entities found in nature. Both natural and synthetic active colloidal systems are often near boundaries or are located in crowded environments. Herein, we describe experiments in which we measured the influence of hydrogen peroxide concentration and dispersed polyethylene glycol (PEG) on the clustering behavior of 5 µm catalytic active Janus particles at low concentration. We found the extent to which clustering occurred in ensembles of active Janus particles grew with hydrogen peroxide concentration in the absence of PEG. Once PEG was added, clustering was slightly enhanced at low PEG volume fractions, but was reduced at higher PEG volumes fractions. The region in which clustering was mitigated at higher PEG volume fractions corresponded to the region in which propulsion was previously found to be quenched. Complementary agent based simulations showed that clustering grew with nominal speed. These data support the hypothesis that growth of living crystals is enhanced with increases in propulsion speed, but the addition of PEG will tend to mitigate cluster formation as a consequence of quenched propulsion at these conditions.