Interfacial Polyelectrolyte–Surfactant Complexes Regulate Escape of Microdroplets Elastically Trapped in Thermotropic Liquid Crystals
Interfacial Polyelectrolyte–Surfactant Complexes Regulate Escape of Microdroplets Elastically Trapped in Thermotropic Liquid Crystals
复制标题
界面聚电解质-表面活性剂复合物调节热致液晶中弹性捕获的微滴的逃逸
DOI：
10.1021/acs.langmuir.1c02580
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发表时间：
2022
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：
Tsuei, Michael;Sun, Hao;Kim, Young-Ki;Wang, Xin;Gianneschi, Nathan C.;Abbott, Nicholas L.
吸附在软界面上的聚电解质用于材料合成、乳液稳定和流变控制等方面。在这里，我们探讨了如何吸附到热致液晶（LC）的水界面的表面活性剂的影响表面活性剂稳定的水微滴被弹性捕获的LC内。研究发现，聚二烯丙基二甲基氯化铵（PDDA）吸附在4-氰基-4 ′-戊基联苯（5CB）相界面上，引发了十二烷基硫酸钠（SDS）修饰的微滴的喷射，这与微滴与液晶界面之间的吸引双电层相互作用相一致.然而，触发微滴释放的PDDA浓度（毫摩尔）比使LC界面电荷饱和的浓度（微摩尔）高三个数量级。观察到的一个短暂的重新取向的LC在逃逸过程中的微滴导致我们得出结论，PDDA和SDS的复合物形成在LC界面，从而调节界面电荷和微滴逃逸。聚（4-苯乙烯磺酸钠）（PSS）也触发逃逸的十二烷基三甲基溴化铵（DTAB）装饰的水微滴从5CB与动力学一致的界面聚电解质-表面活性剂复合物的形成。然而，与PDDA-SDS相反，我们没有观察到使用PSS-DTAB时的LC的瞬时重取向，反映了DTAB和PSS的弱关联和PSS-DTAB复合物形成的缓慢动力学。我们的研究结果揭示了聚电解质-表面活性剂动力学在调节微滴逃逸中的核心作用，更广泛地说，LC提供了一种新的探针的基础，该探针的结构和性质的聚电解质-表面活性剂复合物在界面处。我们展示了这些新的见解的效用，通过触发喷射的微滴从LC使用肽聚合物两亲物，切换其净电荷后，被酶处理。总的来说，我们的研究结果提供了新的见解形成的聚电解质-表面活性剂复合物在水溶液-LC界面和新的原则，设计响应软物质。
Polyelectrolytes adsorbed at soft interfaces are used in contexts such as materials synthesis, stabilization of emulsions, and control of rheology. Here, we explore how polyelectrolyte adsorption to aqueous interfaces of thermotropic liquid crystals (LCs) influences surfactant-stabilized aqueous microdroplets that are elastically trapped within the LCs. We find that adsorption of poly(diallyldimethylammonium chloride) (PDDA) to the interface of a nematic phase of 4-cyano-4′-pentylbiphenyl (5CB) triggers the ejection of microdroplets decorated with sodium dodecylsulfate (SDS), consistent with an attractive electrical double layer interaction between the microdroplets and LC interface. The concentration of PDDA that triggers release of the microdroplets (millimolar), however, is three orders of magnitude higher than that which saturates the LC interfacial charge (micromolar). Observation of a transient reorientation of the LC during escape of microdroplets leads us to conclude that complexes of PDDA and SDS form at the LC interface and thereby regulate interfacial charge and microdroplet escape. Poly(sodium 4-styrenesulfonate) (PSS) also triggers escape of dodecyltrimethylammonium bromide (DTAB)-decorated aqueous microdroplets from 5CB with dynamics consistent with the formation of interfacial polyelectrolyte–surfactant complexes. In contrast to PDDA-SDS, however, we do not observe a transient reorientation of the LC when using PSS-DTAB, reflecting weak association of DTAB and PSS and slow kinetics of formation of PSS-DTAB complexes. Our results reveal the central role of polyelectrolyte–surfactant dynamics in regulating the escape of the microdroplets and, more broadly, that LCs offer the basis of a novel probe of the structure and properties of polyelectrolyte–surfactant complexes at interfaces. We demonstrate the utility of these new insights by triggering the ejection of microdroplets from LCs using peptide–polymer amphiphiles that switch their net charge upon being processed by enzymes. Overall, our results provide fresh insight into the formation of polyelectrolyte–surfactant complexes at aqueous-LC interfaces and new principles for the design of responsive soft matter.