Cloaking Anisotropic Capillary Interactions Through Tunable Nanoscale Surface Topography

通过可调纳米级表面形貌隐藏各向异性毛细管相互作用

• 批准号: 2232579
• 负责人: Peter Beltramo
• 金额: $ 38.19万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232579&HistoricalAwards=false
• 关键词: Cloaking; Anisotropic; Capillary; Interactions; Through

Novel materials, such as solar photovoltaics, antireflective coatings, synthetic membranes, and biosensors, may be engineered for improved performance through the nano- and micro-scale ordering of small particles. Next generation versions of these technologies require ordered two-dimensional structures that have direction-dependent organization. In this project, the research team will investigate a new approach to creating such ordered assemblies of particles using stretched polymer spheres, termed “ellipsoids”. Such particles irreversibly pin to air-water interfaces to conveniently create a two-dimensional layer; however, forces between the particles cause disorganized assemblies to form. This hurdle will be overcome in this project by engineering the interactions between the particles through novel particle synthesis techniques that give the particle surface a controlled degree of roughness. The project will focus on how particle roughness can be designed to dictate the forces between the particles and lead to their ultimate ordered assembly at the air-water interface. By doing this fundamental science, the foundational paradigm to develop two-dimensional materials applicable to a variety of fields, including plasmonics, solar photovoltaics, coatings, membranes, and biosensors, will be established. In addition, several educational and outreach activities are integrated into the project. Undergraduate students from local community colleges will be exposed to opportunities in STEM by recruitment for summer research experiences. The PI will also develop active learning workshops for middle and high school students aimed at increasing interest in STEM fields by exposing students to the exciting real-world applications of particles at interfaces. The project will investigate how nanoscale surface topography (roughness or porosity) dictates the capillary interactions and assembly of anisotropic polymer ellipsoidal particles at fluid interfaces. This work is motivated by the plethora of novel materials (e.g., antireflective coatings, synthetic membranes, hierarchical surfaces, biomimetic materials) enabled from the two-dimensional ordering of anisotropic colloids. However, strong capillary attraction between particles at fluid interfaces dooms anisotropic particle assembly. The central hypothesis is that the capillary forces can be tuned by altering the curvature of the fluid interface surrounding pinned microparticles through the rational design of particles with controlled porosity or roughness. The research team seeks to apply a novel synthetic approach to create polymer ellipsoids with tunable roughness and porosity, quantitatively characterize the capillary interactions between such particles, and ultimately control the microstructural organization of particles whose detrimental capillary interactions have effectively been “cloaked” via their surface topography. First, seeded emulsion polymerization will be used to create biphasic, chemically patchy polymer colloids which can be transformed into rough and porous ellipsoids. Second, the capillary interaction energy between particles will be determined via a combination of monitoring two-particle approach profiles and using Mirau interferometry to measure undulations in particle-liquid contact line with nanometer scale precision. Finally, ordered assemblies will be created using particles with promising interaction energies. By linking the nanoscale particle surface characteristics with interfacial interactions, we will be able to identify design principles for nanoscale surface topography that minimize (i.e., “cloak”) strong capillary interactions to unlock ordered 2D microstructures comprised of anisotropic particles. These well-defined and otherwise inaccessible monolayer assemblies are directly relevant to applications in the fields of energy harvesting, photonics, particle-stabilized emulsions, biological interfaces, membranes, and/or hierarchical materials. The project will include the development of active learning workshops focused on interfacial materials and self-assembly concepts for K-12 educators and school-aged children, as well as expanding access to engineering research opportunities for underrepresented groups through coordination with local community colleges.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.

新型材料，例如太阳能光伏，防反射涂层，合成机制和生物传感器，可以通过小颗粒的纳米和微尺度订购来改善性能。这些技术的下一代版本需要具有方向依赖组织的二维结构。在这个项目中，研究团队将使用拉伸聚合物球来研究一种新的方法来创建这种有序的粒子组合，称为“椭圆形”。这样的颗粒不可逆转地固定在空气水接口到方便地创建二维层。然而，颗粒之间的力会导致杂乱无章的组件形成。通过新型粒子合成技术，通过使粒子表面具有控制的粗糙度，该障碍将在该项目中克服该项目中的相互作用。该项目将重点介绍如何设计颗粒粗糙度来决定颗粒之间的力并导致其在空气水接口处的最终有序组装。通过做这项基本科学，将建立适用于各种领域的二维材料的基础范式，包括浆膜，太阳能光伏，涂料，膜和生物传感器。此外，该项目还将一些教育和外展活动纳入了项目。来自当地社区大学的本科生将通过招募夏季研究经验来接触STEM的机会。 PI还将为中学和高中生开展积极的学习研讨会，旨在通过使学生接触到界面上粒子的真实现实应用，以增加对STEM领域的兴趣。该项目将研究纳米级表面形貌（粗糙度或孔隙率）如何决定流体界面处各向异性聚合物椭圆形颗粒的毛细相互作用和组装。这项工作是由大量新型材料（例如，抗反射涂层，合成机制，分层表面，仿生材料）的造成的，这是由各向异性胶体的二维顺序实现的。然而，流体界面上颗粒之间的强毛细管吸引力注定各向异性颗粒组件。中心假设是，可以通过通过具有控制孔隙度或粗糙度的颗粒的合理设计来调整围绕微粒的流体界面的曲率来调节毛细作用力。研究团队试图采用一种新型的合成方法来创建具有可调粗糙度和孔隙率的聚合物椭球，从定量地表征了这种颗粒之间的毛细血管相互作用，并最终通过其表面地形来控制了颗粒的微观结构组织，这些颗粒的微观结构组织有效地“被粘在一起”。首先，种子乳液聚合将用于产生双相，化学斑点的聚合物胶体，可以转化为粗糙和多孔的椭圆形。其次，粒子之间的毛细管相互作用能将通过监测两粒子接近剖面和使用Mirau干扰来确定颗粒液体接触线中的起伏，并使用纳米尺度的精度来测量起伏。最后，将使用具有承诺相互作用能量的粒子创建有序的组件。通过将纳米级粒子表面特性与交互式相互作用联系起来，我们将能够识别纳米级表面形貌的设计原理，这些设计原理最小化（即“斗篷”）强毛细管相互作用以解锁有序的2D微结构，包括各向异性颗粒的2D微结构。这些定义明确的单层组件与其他明确的单层组件直接相关，与能量收集，光子学，颗粒稳定的乳液，生物学接口，膜和/或分层材料的应用直接相关。 The project will include the development of active learning workshops focused on interfacial materials and self-assembly concepts for K-12 educators and school-aged children, as well as expanding access to engineering research opportunities for underrepresented groups through coordination with local community colleges.This award reflects NSF's statutory mission and has been Deemed honestly of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

项目成果

Nanoscale Porosity in Microellipsoids Cloaks Interparticle Capillary Attraction at Fluid Interfaces

微椭球体中的纳米级孔隙掩盖了流体界面处的颗粒间毛细管吸引力

• DOI: 10.1021/acsnano.3c03301
• 发表时间: 2023
• 期刊: ACS Nano
• 影响因子: 17.1
• 作者: Trevenen, Samuel;Rahman, Md Anisur;Hamilton, Heather S. C.;Ribbe, Alexander E.;Bradley, Laura C.;Beltramo, Peter J.
• 通讯作者: Beltramo, Peter J.

Rough colloids at fluid interfaces: from fundamental science to applications

• DOI: 10.3389/fphy.2023.1248706
• 发表时间: 2023-10
• 期刊: Frontiers in Physics
• 影响因子: 3.1
• 作者: Md Anisur Rahman;P. Beltramo