Polymer Science and Engineering Department, University of Massachusetts , 120 Governors Drive, Conte Center for Polymer Research, Amherst, Massachusetts 01003, United States.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
Langmuir. 2017 Aug 15;33(32):7994-8001. doi: 10.1021/acs.langmuir.7b01685. Epub 2017 Aug 1.
The controlled structuring of liquids into arbitrary shapes can be achieved in biphasic liquid media using the interfacial assemblies of nanoparticle surfactants (NP-surfactants), that consist of a polar nanoparticle "head group" bound to one or more hydrophobic polymer "tails". The nonequilibrium shapes of the suspended liquid phase can be rendered permanent by the jamming of the NP-surfactants formed and assembled at the interface between the liquids as the system attempts to minimize the interfacial area between the liquids. While critical to the structuring process, little is known of the dynamic mechanical properties of the NP-surfactant monolayer at the interface as it is dictated by the characteristics of the component, including NP size and concentration and the molecular weight and concentration of polymers bound to the NPs. Here we provide the first comprehensive understanding of the dynamic mechanical character of two-dimensional NP-surfactant assemblies at liquid/liquid interfaces. Our results indicate that the dynamics of NP-polymer interactions are self-regulated across multiple time scales and are associated with specific mesoscale interactions between self-similar and cross-complementary components. Furthermore, the mechanical properties of the NP-surfactant monolayer are tunable over a broad range and deterministic on the basis of those component inputs. This control is key to tailoring the functional attributes of the reconfigurable structured liquids to suit specific applications.
在双相液体介质中,可以使用由纳米颗粒表面活性剂(NP-表面活性剂)形成的界面组装体将液体控制成任意形状,NP-表面活性剂由极性纳米颗粒“头基团”与一个或多个疏水性聚合物“尾基团”结合而成。当系统试图最小化液体之间的界面面积时,悬浮液相的非平衡形状可以通过形成和组装在液体之间界面处的 NP-表面活性剂的堵塞而永久化。虽然 NP-表面活性剂单层在界面处的动态力学性质对于结构形成过程至关重要,但由于组件的特性(包括 NP 大小和浓度以及与 NPs 结合的聚合物的分子量和浓度)的影响,对其了解甚少。在这里,我们首次全面了解了液体/液体界面处二维 NP-表面活性剂组装体的动态力学特性。我们的结果表明,NP-聚合物相互作用的动力学在多个时间尺度上是自我调节的,并且与自相似和交叉互补组件之间的特定介观相互作用有关。此外,NP-表面活性剂单层的机械性能可以在宽范围内进行调节,并基于这些组件输入进行确定性调节。这种控制是根据特定应用需求调整可重构结构化液体的功能属性的关键。