EAGER: Dynamic Modification of the Spectral Radiative Properties of a Fluid via Core-Shell Multifunctional Nanoparticles

该项目旨在动态控制分散在流体中的纳米粒子的光谱辐射特性。已知纳米颗粒为热传输提供各种益处，并且在此特别相关的是，可以通过纳米颗粒的分散实现对辐射性质的巨大改变。随着纳米颗粒的出现，可以控制分散体的辐射特性，而不仅仅是被动地观察这些特性。特别地，将产生核-壳多功能纳米颗粒的分散体，其能够动态地改变它们的体积并因此改变它们的光谱辐射性质。初步实验表明，这些多功能纳米粒子能够合成，以实现温度敏感的体积变化。迄今为止，这些颗粒中的大多数已经用聚合物壳和无机核合成，而该提案计划用聚合物核和无机及金属壳来逆转这一点，以实现可见光-红外波长的大辐射性质转变。该提案通过一系列全面的实验和分析来解决这一问题。实验将主要集中在测量光谱辐射特性的不同分散体在不同的温度，从而不同的体积使用分光光度技术。然后将这些测量结果与建模结果相关联，以提高对辐射传输的动态控制的基本理解，作为核材料、壳材料、尺寸和可实现的体积偏移的函数。.拟议项目的潜在变革性质是动态（和可逆）改变纳米颗粒分散体的辐射特性的令人兴奋的能力。基本问题将得到解决，如：可以控制核壳多功能纳米粒子的单一分散体，使其可以作为吸收剂，或作为能量的发射体？能否以被动的方式实现这种控制？这是否可以使用成本效益高、环境友好的材料来实现？通过耦合多功能纳米粒子提供的动态能力的辐射特性控制创新的被动控制方法将被调查解决进一步的问题，如：体积变化是否会受到温度变化的影响？ 分散体可以经历多少次可逆的体积变化过程？这些核壳材料中引起吸光度变化的基本结构-性质关系是什么？如何调整这种关系？该项目更广泛的影响来自于通过在拟议的纳米颗粒分散体中开发动态可控的辐射特性而可能带来的技术机会。这种系统可能产生的一个潜在系统是两用太阳能集热器和夜空散热器。使用纳米颗粒作为直接吸收接收器已经显示出提供比传统的基于表面的接收器更高的效率。另一个有趣的选择是创造热光开关的能力。这样的开关将允许创建有时透明而在其他时间可以是不透明的液体过滤器。另一个影响在于本科生研究的方向和招收代表性不足的少数民族。

Abstract1262201OtanicarThe project aims to dynamically control the spectral radiative properties of nanoparticles dispersed in a fluid. Nanoparticles are known to offer a variety of benefits for thermal transport, and of particular relevance here the vast changes to the radiative properties that can be achieved through the dispersion of nanoparticles. With the advent of nanoparticles it is possible to control the radiative properties of dispersions as opposed to just passively observing such properties. In particular, a dispersion of core-shell multifunctional nanoparticles will be created that are capable of dynamically changing their volume and thus their spectral radiative properties. Preliminary experiments have shown that these multifunctional nanoparticles are capable of being synthesized to achieve temperature sensitive volumetric changes. To date most of these particles have been synthesized with polymer shells and inorganic cores while this proposal plans to reverse this with polymer cores and inorganic and metallic shells to achieve large radiative property shifts in the visible-infrared wavelengths. This proposal addresses this question through a comprehensive set of experiments and analyses. The experiments will largely focus on measuring the spectral radiative properties of different dispersions at different temperatures and thus different volumes using spectrophotometric techniques. These measurements will then be correlated with modeling results to improve fundamental understanding of the dynamic control of radiative transport as a function of the core material, shell material, size and volumetric shift achievable. . The potentially transformative nature of the proposed project is the exciting capability to dynamically (and reversibly) change the radiative properties of a dispersion of nanoparticles. Fundamental questions will be addressed such as: can a single dispersion of core-shell multifunctional nanoparticles be controlled so that it can serve as either an absorber, or as an emitter of energy? Can this control be achieved in a passive manner? Can this be done using cost effective, environmentally benign materials? By coupling radiative property control with the dynamic capabilities offered by multifunctional nanoparticles innovative passive control methods will be investigated addressing further questions such as: Can volumetric changes be effected with changes in temperature? How many times can the dispersion go through the reversible volume change process? What are the fundamental structure-property relationships in these core-shell materials that give rise to changes in absorbance and how can this relationship be tuned? The broader impacts of this project come from the technological opportunities that may be enabled by developing dynamically controllable radiative properties within the proposed nanoparticle dispersions. One potential system that may result from such a system is a dual-use solar thermal collector and night-sky radiator. The use of nanoparticles acting as direct absorption receivers has been shown to offer improved efficiencies over conventional surface-based receivers. Another intriguing option is the ability to create a thermo-optical switch. Such a switch would allow for creating a liquid filter that at times is transparent while at other times could be opaque. Another impact lies in the direction of undergraduate research and the recruitment of under-represented minority.