Thermal Evaporation around Optically-Excited Functionalized Nanoparticles

光学蒸发器辅助的热蒸发可以实现各种创新的可再生能源应用，从水净化到化学分馏。其中许多应用可以催化新的行业，从而推动全球经济增长。例如，利用太阳能生产淡水的能力将解决水-能源关系中的许多挑战。本项目的动机是最近观察到的液体蒸发使用功能化的光吸收纳米粒子的高度局部化的加热效应。在这样的演示中，在本体温度保持在约30摄氏度的同时产生水蒸气。其基础物理学尚未被理解，其机制与复杂的多相（液体-蒸汽-固体）传热和传质有关，需要这种多学科研究来解开。从该项目中获得的基本热传输科学预计将指导开发利用太阳能的新技术，从而对应用产生更广泛的影响。该项目将使来自大学中代表性不足群体的研究生和本科生能够接受教育和培训，该项目的驱动假设是，增强的界面热传输和自组装单层缺陷辅助成核联合收割机结合起来，以增强气泡的产生，并改善总体蒸发效果。为了验证这一假设，本提案的目标是（1）通过分子模拟和介观流体动力学建模的组合来理解气泡动力学中表面功能化、热传输和随后的质量传输之间的基本关系;以及（2）通过光激发功能化纳米颗粒周围的蒸汽生成实验来验证这种关系。该项目将采用分子模拟，中尺度建模和实验验证相结合，以前所未有的分辨率实现对这一基本问题的多尺度理解。

Optical absorber-assisted thermal evaporation can enable a variety of innovative renewable energy applications, ranging from water purification to chemical fractionation. Many of these applications can catalyze new industries and hence drive global economic growth. For example, the ability to use solar energy for fresh water production will tackle many challenges in the water-energy nexus. The present project is motivated by a recently observed liquid evaporation using highly localized heating effect from functionalized light absorbing nanoparticles. In such a demonstration, water vapor was generated while the bulk temperature remained at about 30 degrees C. The underlying physics is not yet understood, and the mechanism is related to the convoluted multi-phase (liquid-vapor-solid) thermal and mass transport, which needs this multi-disciplinary study to unlock. The fundamental thermal transport science to be gained from this project is expected to guide the development of new technologies to utilize solar energy, resulting in significant broader impacts on applications. This project will enable the education and training of graduate students and undergraduate students from under-represented groups in the universities.This project is driven by the hypothesis that enhanced interfacial thermal transport and the self-assembled monolayer defect-assisted nucleation combine to enhance bubble generation and improve the overall evaporation effect. To test this hypothesis, the objectives of this proposal are to (1) understand the fundamental relationship between the surface functionalization, thermal transport and the subsequently mass transport in bubble dynamics through a combination of molecular simulations and mesoscale hydrodynamics modeling; and (2) validate such a relationship through experiments on vapor generation around photo-excited functionalized nanoparticles. This project will employ a combination of molecular simulation, mesoscale modeling and experimental validation to achieve a multi-scale understanding of this fundamental problem with unprecedented resolution.