Collaborative Research: Liquid Phase Atomic Layer Deposition of Thin Films on Nanoparticles Using Three-Dimensionally Printed Microfluidics

纳米粒子是尺寸在1到100纳米之间的粒子，由于其高表面积体积比而具有独特的尺寸依赖性质。功能性纳米颗粒在药物输送、磁共振成像、可再生能源、光电子学和催化等方面的应用具有造福社会的潜力。这些应用依赖于使用薄膜涂层精确定制纳米颗粒表面化学性质的能力。纳米颗粒薄膜涂层通常只有几层厚度，但必须均匀地涂在单个纳米颗粒上。该奖项支持对一种新的高精度薄膜纳米颗粒涂层策略的基础研究，该策略通过结合原子层沉积，三维打印和微流体原理，克服当前制造挑战，包括涂层不均匀性。改善纳米颗粒涂层的均匀性，使功能性纳米颗粒在卫生、能源和技术领域得到新的应用。该研究奖通过纳米粒子应用的实际教育示范，支持公众参与纳米技术，重点是促进历史上在制造业研究中代表性不足的群体，如妇女和少数民族的参与。纳米颗粒薄膜涂层目前面临的挑战包括颗粒聚集、涂层不均匀、厚度控制有限以及对颗粒尺寸和形貌的敏感性不佳。该研究奖项通过将传统原子层沉积的单层沉积原理与流体动力学纳米颗粒操作方法（称为确定性横向位移）相结合，实现了一种称为“液相原子层沉积”的新型纳米制造技术，从而应对了这些挑战。这种方法代表了从基于固气界面沉积的传统原子层沉积到基于固液界面连续吸附和沉积反应的新沉积物理的转变。该研究的重点是利用微流控通道内特殊定位的纳米柱，被动地将悬浮的纳米颗粒输送到连续的反应物和洗涤溶液的离散、相邻的流中。假设控制液相原子层沉积的固液界面现象可获得高精度和均匀性的纳米颗粒薄膜涂层。基于双光子直接激光书写的增材制造技术构建了平行三维微流控反应器，保证了该方法的高通量。研究小组通过基础实验研究、计算流体动力学模拟和多物理场有限元建模等方法研究了液相原子层沉积现象。该奖项反映了美国国家科学基金会的法定使命，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。

Nanoparticles are particles between 1 and 100 nanometer in size that possess unique, size-dependent properties due to their high surface area-to-volume ratios. Functional nanoparticles have the potential to benefit society through applications such as drug delivery, magnetic resonance imaging, renewable energy, optoelectronics, and catalysis. These applications rely on an ability to precisely customize the surface chemistry of nanoparticles using thin-film coatings. Nanoparticle thin-film coatings are typically on the order of a few monolayers in thickness, yet must be uniformly applied to individual nanoparticles. This award supports fundamental research into a new, high-precision thin-film nanoparticle coating strategy that overcomes current manufacturing challenges, including coating non-uniformity, by combining principles of atomic layer deposition, three-dimensional printing, and microfluidics. Improving the uniformity of nanoparticle coatings enables new applications of functional nanoparticles across health, energy, and technology sectors. This research award supports public engagement with nanotechnology through hands-on educational demonstrations of nanoparticle applications, with a focus on promoting inclusion for groups historically underrepresented in manufacturing research such as women and minorities. Current challenges in thin-film coating of nanoparticles include particle aggregation, non-uniform coating, limited thickness control, and undesired sensitivity to particle size and morphology. This research award meets these challenges by combining the monolayer-by-monolayer deposition principle of conventional atomic layer deposition with the hydrodynamic nanoparticle manipulation approach known as deterministic lateral displacement to achieve a new nanomanufacturing technology termed 'Liquid Phase Atomic Layer Deposition'. This approach represents a shift from conventional atomic layer deposition based on deposition at the solid-vapor interface to a new deposition physics based on successive adsorption and deposition reactions at the solid-liquid interface. The research studies center on utilizing specially positioned nanoposts within a microfluidic channel to passively transport suspended nanoparticles into discrete, adjacent flow streams of successive reactant and wash solutions. It is hypothesized that the controlled solid-liquid interface phenomena of Liquid Phase Atomic Layer Deposition yields a high degree of precision and uniformity for nanoparticle thin-film coating. The engineering of parallel three-dimensional microfluidic reactors, constructed by means of two-photon direct laser writing-based additive manufacturing, ensures that this method is also high throughput. The research team investigates the phenomenon of Liquid Phase Atomic Layer Deposition through fundamental experimental studies, computational fluid dynamics simulations, and multiphysics finite element modeling.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.