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

纳米颗粒是大小在1到100纳米之间的颗粒，由于其高比表面积与体积比，具有独特的、与尺寸相关的属性。功能纳米粒子通过药物输送、磁共振成像、可再生能源、光电子学和催化等应用，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的能力。纳米颗粒薄膜涂层通常只有几个单分子层的厚度，但必须均匀地涂覆在单个纳米颗粒上。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来克服当前的制造挑战，包括涂层不均匀。提高纳米粒子涂层的均匀性使功能纳米粒子能够在卫生、能源和技术部门得到新的应用。该研究奖通过纳米颗粒应用的实践教育演示，支持公众参与纳米技术，重点是促进制造业研究中历史上代表性不足的群体，如妇女和少数族裔。目前纳米粒子薄膜包覆面临的挑战包括粒子聚集、包覆不均匀、厚度控制受限以及对粒子大小和形态的不期望敏感性。该研究奖通过将传统原子层沉积的单层-单层沉积原理与被称为确定性横向位移的流体动力学纳米颗粒操纵方法相结合来应对这些挑战，从而实现了一种名为“液态原子层沉积”的新纳米制造技术。这种方法代表了从传统的基于固-气界面沉积的原子层沉积向基于固-液界面连续吸附和沉积反应的新的沉积物理的转变。研究的重点是利用微流控通道中特殊定位的纳米孔被动地将悬浮的纳米颗粒输送到连续反应物和洗涤液的离散、相邻的流动中。通过对液相原子层沉积过程中固-液界面控制现象的研究，提出了纳米粒子薄膜镀膜的高精度、高均匀性的设想。基于双光子直接激光写入的加法制造的平行三维微流控反应器的工程，确保了这种方法也是高产量的。该研究小组通过基础实验研究、计算流体力学模拟和多物理有限元建模来研究液态原子层沉积现象。这一奖项反映了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。

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.