Fabrication of mesoporous nanoparticle structures via co-solvent evaporation

过渡金属介孔材料在催化、传感、锂离子电池等领域具有广阔的应用前景。通常，这些介孔结构通过两亲性表面活性剂和过渡金属纳米颗粒（NP）的溶剂蒸发诱导自组装（EISA）获得。由于NP在溶液中的高反应性，NP-NP和NP-表面活性剂之间的相互作用强烈地依赖于溶剂浓度。由于这些依赖于浓度的相互作用在蒸发过程中发生变化，结构形成的动力学变得依赖于过程。在这个项目的延续中，我们将设计一个新的模拟方案来捕捉这些依赖于过程的特征，并研究TM介孔薄膜的形成动力学。采用连续介质模型研究了共溶剂的蒸发过程，其中两种溶剂的浓度通过数值求解具有移动边界条件的扩散方程得到。随后，这些随时间变化的溶剂浓度将被用来表征粒子模拟中的NP-NP和NP-单体相互作用，粒子模拟使用计算效率高的软粗粒度模型。NP-NP和NP-表面活性剂之间的强相互作用在小溶剂浓度下发生，引起不可逆的聚集，其由交联表示。这种计算效率的连续介质模型和粒子模拟相结合，将使我们能够探索，理解和优化的工艺条件，制造有序的TM介观结构。

Transition metal mesoporous materials have promising applications in catalysis, sensing, and lithium-ion batteries. Typically these mesoporous structures are obtained by solvent evaporation induced self-assembly (EISA) of amphiphilic surfactants and transition metal nanoparticles (NP). Due to the high reactivity of NPs in solution, the interactions between NP-NP and NP-surfactants strongly depend on the solvent concentrations. Since these concentration-dependent interactions vary in the course of evaporation, the kinetics of structure formation becomes process-dependent.In this continuation of project, we will devise a new simulation scheme to capture these process-dependent features and study the formation kinetics of TM mesoporous thin films. The co-solvent evaporation is investigated by continuum models, where the two solvent concentrations are obtained by numerically solving diffusion equations with a moving boundary condition. Subsequently, these time-dependent solvent concentrations will be employed to characterize the NP-NP and NP-monomer interactions in particle simulations, which use a computationally efficient, soft, coarse-grained models. Strong interactions between NP-NP and NP-surfactants, which occur at small solvent concentrations, give rise to an irreversible aggregation, which is represented by crosslinks. This computationally efficient combination of continuum model and particle simulation will allow us to explore, understand, and optimize the process conditions for the fabrication of well-ordered TM mesostructures.