Collaborative Research: ISS: Microgravity enabled studies of particle adsorption dynamics at fluid interfaces

载粒液滴因其在乳化液、催化、传感、光学材料以及环境修复等方面的应用而备受关注。创建充满颗粒的流体界面的一个重要步骤是将颗粒输送和附着(吸附)到液滴。不幸的是，直接研究地球上的附着过程以及分散在流体主体中的颗粒的沉积(重力沉降)的竞争效应是具有挑战性的。换句话说，附着在流体界面上的颗粒和由于重力而沉降的颗粒之间存在竞争。为了减轻重力的影响，该奖项旨在研究国际空间站在微重力下颗粒与流体界面的吸附。该项目将阐明在没有沉淀的情况下颗粒如何附着到液滴上的关键步骤。这一奖项的发现将导致工程战略，以优化依赖于颗粒界面的材料设计。从技术的角度来看，所获得的知识将直接应用于添加剂制造和影响地球生命的光学材料的新兴技术。颗粒稳定乳状液的稳定性很大程度上依赖于界面处的颗粒覆盖率。颗粒吸附过程中的动力学限制限制了Pickering乳液充分发挥其技术潜力。该奖项旨在通过发展：1)流体界面结构-性质(表面压力-面积分数)关系的基本知识，2)理解流体界面从流体到玻璃(迟滞)动力学的转变，以及3)描述扩散限制吸附的经验证的模型，从而促进我们对界面颗粒吸附的理解。该奖项旨在通过在微重力下进行实验，了解限制颗粒吸附到流体界面的机制。微重力实验是必要的，可以在没有沉淀的情况下研究吸附动力学。到流体界面的渐变扩散的时间尺度可能是几个小时的量级，这使得抛物线飞行不是避免重力影响的现实选择。虽然关键实验将在微重力下进行，但这项工作的科学和技术影响将使地球上的生命受益。这一发现将有利于任何涉及颗粒吸附到流体界面的过程，包括制造、消费品、浮选、石油回收和环境修复。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。

Particle-laden droplets have received attention for their applications in emulsions, catalysis, sensing, optical materials, as well as environmental remediation. An important step in creating particle-laden fluid interfaces is the transport and attachment (adsorption) of the particles to a fluid droplet. Unfortunately, it is challenging to study directly the attachment process on Earth with the competing effects of sedimentation (gravitational settling) of the particles dispersed in the bulk of the fluid. In other words, there is competition between particles attaching to a fluid interface and settling because of gravity. To alleviate the effect of gravity, this award aims to study adsorption of particles to fluid interfaces under microgravity in the international space station. The project will elucidate the critical steps of how particles attach to droplets in the absence of sedimentation. Findings from this award will lead to engineering strategies to optimize the design of materials that rely on particle-laden interfaces. From a technological standpoint, the knowledge gained will be directly applicable to emerging technologies in additive manufacturing and optical materials to impact life on Earth. The stability of particle-stabilized emulsions strongly depends on the particle coverage at the interface. Kinetic limitations during particle adsorption limit Pickering emulsions from reaching their full technological potential. This award aims to advance our understanding of particle adsorption at interfaces by developing: 1) fundamental knowledge in structure-property (surface pressure-area fraction) relationships at fluid interfaces, 2) an understanding of the transition from fluid to glassy (sluggish) dynamics at fluid interfaces, and 3) a validated model describing diffusion-limited adsorption. This award aims at understanding the mechanisms limiting the adsorption of particles to fluid interface by conducting experiments in microgravity. Microgravity experiments are necessary and allow to investigate adsorption dynamic in the absence of sedimentation. The time scale for gradient diffusion to a fluid interface can be of order of hours, making parabolic flights not a realistic option to avoid gravitational effects. While key experiments will be conducted under microgravity, the scientific and technological impacts of the work will benefit life on Earth. Findings will benefit any processes involving particles adsorption to fluid interfaces including in manufacturing, consumer products, flotation, oil recovery, and environmental remediation.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.