Structural Control at Fluidic Interfaces with Nanoparticle Surfactant Assemblies

这个项目将使用合成、实验和数值模拟来研究不相容液滴的动力学，这些液滴被纳米颗粒(NP)包裹在液滴和周围液体之间的界面上。用纳米颗粒包裹液滴可以防止液滴彼此粘合，这使得这种特殊的乳状液备受关注。优先相互作用的NPs的混合物将被合成，以便它们在界面上经历相分离，产生在其界面上具有不同NPs的斑块区域的液滴。以这种方式定制界面结构将能够控制大量液滴在被迫紧密堆积在一起时所呈现的空间排列。该技术可用于制造在相邻液滴之间具有不同互联点和通道的物体。这种结构将提供用于将电荷、颗粒或化学品从一个隔室输送到另一个隔室的转导路径，并将形成具有受控光学、磁性和传输特性的材料的基础。研究小组将为初中和高中生在STEM极其重要的培训领域开展外联活动，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，并将有助于为所有参与者提供教育渠道。该项目的目标是设计在液滴界面上相分离的功能化纳米颗粒，以促进液滴的受控3D排列，并最终形成具有独特性质的宏观结构。分散在一种液体中的NP包覆有溶解在另一种不相容液体中的配体，是与界面具有高结合能的纳米粒子表面活性剂。该项目将探索使用功能化NP混合物的异质界面组装，这些混合物经过2D相分离，形成具有不同NP结构域的液滴，从中将产生分层的液滴组装。此外，在液-液界面上的NP重组可以产生液滴间通道，作为一个相互连接的、分隔的系统，具有由配体和2D相分离形态之间的相互作用决定的转导路径，用于传输、分离和流动介质。该项目将侧重于功能化纳米颗粒表面活性剂组件(NSA)的基本基础。实验将探索用于生成NSA的配体功能化NPs的合成，以及NSA在液滴上的结构和动力学的原位表征。它们将伴随着预测混合NSA的相行为的模拟和混合NSA的宏观3D阵列的研究。该项目的成果将在包括添加剂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的专业发展提供机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.