Characterization of Adsorbate-Induced Ordering Transitions of Liquid Crystals within Monodisperse Droplets
Characterization of Adsorbate-Induced Ordering Transitions of Liquid Crystals within Monodisperse Droplets
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DOI：
10.1021/la900786b
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发表时间：
2009-08-18
期刊：
影响因子：
3.9
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
--
作者：
Gupta, Jugal K.;Zimmerman, Jacob S.;Abbott, Nicholas L.
众所周知，微米级液滴内液晶（lc）的有序程度很大程度上取决于界面吸附物的存在，尽管伴随着界面锚定从切向垂直变化的有序平衡状态的确切顺序尚未确定。在本文中，我们报告了一种允许在水相中制备运动分散的LC液滴的方法，以研究LC液滴在水-LC液滴界面上随两亲体吸附而发生的有序转变。通过使用所有在水-LC界面进行可逆吸附的两亲体（十二烷基硫酸钠，SDS），我们确定了LC液滴的六种不同拓扑有序状态，作为SDS浓度增加的函数。我们利用SDS在直径为8.0 +/- 0.2 μ m的LC液滴上的可逆吸附来证实这些拓扑状态是平衡状态。我们还将LC液滴暴露在连续梯度的SDS浓度中，以记录拓扑状态之间的连续转换，并证实LC液滴在水分散体中没有额外的中间拓扑状态形成，这也使得所有由生物分子相互作用驱动的LC液滴的有序转换的研究成为可能。磷脂酶A(2)在LC液滴界面处对磷脂l -双棕榈酰磷脂酰胆碱（L-DLPC）进行酶解，可以触发LC的拓扑有序态的进展，与SDS观察到的相同。总的来说，本文提出的结果通过提供关于LC液滴中遇到的拓扑有序态的一组明确的观察结果，解决了文献中先前的冲突数据。本文提供了一个数据集，可以对未来的LCs理论和模拟进行比较，以发展对液滴中体积效应和界面效应之间竞争的基本理解。结果还表明，可以利用LC液滴的拓扑有序转变来报告界面酶促反应。
The ordering of liquid crystals (LCs) within micrometer-sized droplets is known to depend strongly oil the presence of interfacial adsorbates, although the exact sequence of ordered equilibrium states that accompany a change in interfacial anchoring from tangential to perpendicular has not been established. In this paper, we report use of a methodology that permits the preparation of motiodisperse LC droplets in aqueous phases to investigate ordering transitions ill the LC droplets that accompany the adsorption of amphiphiles at the aqueous-LC droplet interface. By using all amphiphile that undergoes reversible adsorption at the aqueous-LC interface (sodium dodecylsulfate, SDS), we identified six distinct topologically ordered states of the LC droplets as a function of increasing concentration of SDS. We exploited the reversible adsorption of the SDS to LC droplets with diameters of 8.0 +/- 0.2 mu m to confirm that these topological states are equilibrium ones. We also exposed LC droplets to a continuous gradient in concentration of SDS to document the continuous transitions between topological states and to confirm the absence of additional, intermediate topological states formation of the LC droplets as aqueous dispersions also enabled all investigation of ordering transitions in The C LC droplets driven by biomolecular interactions, Surprisingly, enzymatic hydrolysis of the phospholipid L-dipalmitoyl phosphalidylcholine (L-DLPC) by phospholipase A(2) at the interfaces of the LC droplets was observed to trigger the same progression of topologically ordered states of the LC as was observed with SDS. Overall, the results presented ill this paper resolve prior conflicting data in the literature by providing an unambiguous set of observations regarding topologically ordered states encountered in LC droplets. This paper provides a data set against which future theories and simulations of LCs can be compared to develop a fundamental understanding of the competition between volumetric and interfacial effects in droplets. The results also suggest that topological ordering transitions ill LC droplets call be exploited to report interfacial enzymatic reactions.