Structural Control at Fluidic Interfaces with Nanoparticle Surfactant Assemblies

该项目将使用合成，实验和数值模拟来研究在液滴和周围液体之间的界面处被纳米颗粒（NP）包裹的不混溶液滴的动力学。 用NP包裹液滴防止液滴彼此聚结，这使得这种特殊类型的乳液引起了极大的兴趣。将合成优先彼此相互作用的NP的混合物，使得它们在界面处经历相分离，产生在其界面上具有不同NP的斑块区域的液滴。以这种方式调整界面的结构将能够控制大量液滴被迫紧密聚集在一起时所呈现的空间布置。该技术可用于生产在相邻液滴之间具有不同互连点和通道的物体。 这样的构建体将为电荷、颗粒或化学物质从一个隔室到另一个隔室的运输提供转导途径，并且将形成具有受控的光学、磁性和运输性质的材料的基础。 研究团队将在STEM培训的关键领域为初中和高中学生开展外展活动，并亲自参与实验室研究。在早期教育阶段加强STEM的基本原则将有助于解决来自代表性不足群体的学生的机会不平等问题，并将有助于建立一个有利于所有参与者的教育管道。该项目的目标是设计功能化纳米颗粒，这些纳米颗粒在液滴界面上相分离，以促进液滴的可控3D排列，最终，形成具有独特性质的宏观结构。 分散在一种液体中的纳米颗粒用溶解在第二不混溶液体中的配体涂覆，是具有高界面结合能的纳米颗粒表面活性剂。 该项目将探索使用官能化NP混合物的异质界面组装体，这些混合物经历2D相分离以形成具有不同NP域的界面的液滴，从该界面将产生液滴的分层组装体。 此外，在液-液界面处的NP重组可以产生液滴间通道，作为具有转导途径的互连的、区室化的系统，所述转导途径由配体和2D相分离的形态之间的相互作用决定，用于输送、分离和流通介质。该项目将侧重于功能化纳米粒子表面活性剂组件（NSA）的基本基础。 实验将探索用于生成NSA的配体官能化NP的合成以及对液滴上的NSA的结构和动力学的原位表征。他们将伴随着模拟预测混合NSA的相行为和混合NSA的宏观3D阵列的调查。 该项目的成果将在包括增材制造在内的重要技术领域开辟新的机会，同时为纳米工程交叉领域的研究人员提供专业发展机会。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will use synthesis, experiments, and numerical simulations to examine the dynamics of immiscible liquid drops that are encased by nanoparticles (NPs) at the interface between the drop and surrounding liquid. Encasing the drop with NPs prevents the drops from coalescing with each other, which makes this special kind of emulsion of great interest. A mixture of NPs that preferentially interact with each other will be synthesized so that they undergo a phase separation at the interface, producing drops that have patchy areas of different NPs on their interfaces. Tailoring the structure of the interface in this way will enable control over the spatial arrangement that a large collection of drops assumes when they are forced to pack closely together. This technique can be used to produce objects with distinct interconnection points and channels between adjacent drops. Such constructs would provide access to transduction pathways for the transport of charges, particulates, or chemicals from one compartment to another and would form the basis for materials with controlled optical, magnetic and transport properties. The research team will develop outreach activities for junior high and high school students in critically important areas of STEM training with hands-on participation in laboratory research. This reinforcement of foundational principles in STEM at early educational stages will help address opportunity inequities of students from underrepresented groups and will contribute to an educational pipeline for the benefit of all participants.The goal of this project is to design functionalized nanoparticles that phase separate on the interface of liquid drops in ways that promote controlled 3D arrangements of drops and, ultimately, the formation of macroscopic structures with unique properties. NPs dispersed in one liquid that are coated with ligands dissolved in a second immiscible liquid are nanoparticle surfactants with high binding energy to the interface. The project will explore using heterogeneous interfacial assemblies of functionalized NP mixtures that undergo 2D phase separation to form droplets with interfaces having distinct NP domains from which hierarchical assemblies of drops will be generated. Furthermore, NP reorganization at the liquid-liquid interface can generate inter-droplet channels as an interconnected, compartmentalized system having transduction pathways, dictated by the interactions between the ligands and the 2D phase separated morphologies, for transport, separations, and flow-through media. The project will focus on the fundamental underpinnings of functionalized nanoparticle surfactant assemblies (NSAs). Experiments will probe the synthesis of ligand-functionalized NPs for generating NSAs and the in situ characterization of the structure and dynamics of NSAs on liquid droplets. They will be accompanied by simulations that predict the phase behavior of mixed NSAs and investigation of macroscopic 3D arrays of mixed NSAs. Results from the project will open new opportunities in technologically important areas, including additive manufacturing, while providing opportunities for the professional development of researchers at the intersection of nanoscale engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.