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

1262201Otanicar该项目旨在动态控制分散在流体中的纳米颗粒的光谱辐射特性。众所周知，纳米颗粒为热传输提供了各种好处，尤其是通过纳米颗粒的分散可以实现辐射特性的巨大变化。随着纳米粒子的出现，有可能控制分散体的辐射特性，而不是仅仅被动地观察这些特性。特别是，将创造一种核壳多功能纳米颗粒的分散体，能够动态改变它们的体积，从而改变它们的光谱辐射特性。初步实验表明，这些多功能纳米颗粒能够被合成来实现温度敏感的体积变化。到目前为止，大多数这些粒子都是用聚合物壳和无机核合成的，而本提案计划用聚合物核和无机和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变化。该提案通过一系列全面的实验和分析解决了这一问题。实验将主要集中在使用分光光度技术测量不同分散体在不同温度下的光谱辐射特性，从而测量不同体积的光谱辐射特性。然后，将这些测量结果与模拟结果相关联，以提高对作为核心材料、外壳材料、尺寸和可实现的体积移动的函数的辐射传输的动态控制的基本理解。。拟议项目的潜在变革性是具有激动人心的能力，能够动态(和可逆地)改变纳米颗粒分散体的辐射特性。基本问题将被解决，例如：核壳多功能纳米颗粒的单一分散体能否被控制，使其既可以作为能量的吸收者，也可以作为能量的发射者？这种控制能否以被动的方式实现呢？能否使用经济实惠、环保的材料来实现这一点？通过将辐射性能控制与多功能纳米颗粒提供的动态能力相结合，将研究创新的被动控制方法，以解决进一步的问题，例如：体积变化是否会随着温度的变化而影响？分散体可以经历多少次可逆的体积变化过程？在这些核壳材料中，导致吸光度变化的基本结构-性质关系是什么？这种关系如何调整？该项目的更广泛影响来自于可能通过在拟议的纳米颗粒分散体内开发动态可控的辐射特性而实现的技术机会。这种系统可能产生的一个潜在系统是一个两用的太阳能集热器和夜空辐射器。使用纳米颗粒作为直接吸收接收器已被证明比传统的基于表面的接收器提供了更高的效率。另一个耐人寻味的选择是制造热光开关的能力。这样的切换将允许创建一种液体过滤器，该过滤器有时是透明的，而有时可能是不透明的。另一个影响在于本科生研究的方向和招募代表不足的少数族裔。

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.