DMREF: Collaborative Research: Design of active ink for 3D printing: integrating modeling and experiments

该奖项支持一个由四名研究人员组成的多学科团队，他们使用建模、分析、计算机模拟和实验来研究使用活性颗粒悬浮液来增强3D打印应用中油墨的性能。以合成自推进颗粒悬浮液为代表的活性物质从其环境中获取能量，并改变周围流体的性质。它们具有新颖的材料性能和广阔的应用前景。本文介绍了一种新的3D打印油墨概念--“活性油墨”。即使是流体中的一小部分活性自推进颗粒，也会显著降低粘度，增强油墨通过喷嘴的传输，并提高印刷速度。该项目将促进新材料的设计和制造，大大缩短从原型到产品的路径。这项研究还将使学生和博士后能够进行高度多学科的培训和教育，他们将学习应用数学和计算的理论技术，以及化学和纳米制造中使用的实验技术。除了开发新的3D打印技术外，这项工作还将带来新的数学模型和高效的计算算法。研究人员将研究由于合成自推进颗粒的存在而大幅降低活性油墨的有效粘度和增加自扩散系数。有效粘度的降低将增强油墨通过喷嘴的传输。有效自扩散系数的增加将使聚合速度更快，从而提高分辨率和更准确的3D特征设计。此外，由于它们对外加剪切流的响应完全不同，活性颗粒的使用可能会导致设计出具有新的颗粒分布的复合材料。活性粒子的功能化也将允许调节硬化聚合物的性质。将开发新的数学模型，并对其进行数值和解析分析。他们的预测将得到实验验证。对基于动力学理论的连续介质偏微分方程模型进行了渐近分析和数值分析。这里的一个关键挑战是利用不动点理论和拓扑度理论的方法来寻找定常流解。在基于粒子的模型的模拟中，挑战是准确地捕捉到当活性棒移动时发生的反应的动力学。模拟连续介质模型的一个困难是将分子尺度的反应纳入到中尺度方法中。通过解决这些挑战，这些计算方法的实用性和适用性将显著扩大，使它们能够用于模拟范围广泛的多组分动态系统。

This award supports a multidisciplinary team of four investigators using modeling, analysis, computer simulations, and experiments to study using suspensions of active particles to enhance the properties of inks for applications in 3D printing. Active materials represented by suspensions of synthetic self-propelled particles harvest energy from their environment and alter the properties of the surrounding fluid. They have novel materials properties and promising applications. Here, a new concept of ink for 3D printing, termed "active ink", is introduced. Even a small fraction of active self-propelled particles in a fluid results in a dramatic reduction of viscosity, enhancing ink transport through the nozzle and increasing printing speed. This project will facilitate the design and manufacture of new materials, significantly shortening the path from prototype to product. This research will also enable a highly multidisciplinary training and education of students and postdocs who will learn theoretical techniques in applied mathematics and computations, as well as experimental techniques employed in chemistry and nanofabrication. Apart from the development of new 3D printing technology, the work will lead to novel mathematical models and efficient computational algorithms.A drastic reduction of effective viscosity and increase of self-diffusivity of the active ink due to the presence of synthetic self-propelled particles will be studied. The reduction of the effective viscosity will enhance ink transport through the nozzle. The increase of the effective self-diffusivity will enable faster polymerization resulting in resolution enhancement and more accurate 3D feature design. In addition, due to their fundamentally different response to applied shear flow, the use of active particles may lead to the design of composite materials with novel distributions of particles. The functionalization of active particles also will allow tuning the properties of the hardened polymer. New mathematical models will be developed and analyzed both numerically and analytically. Their predictions will be experimentally verified. The continuum partial differential equation model based on kinetic theory will be analyzed asymptotically and numerically. A key challenge here is to find stationary flow solutions by employing methods from fixed-point and topological degree theory. In simulations of particle-based models, the challenge is to accurately capture the dynamics of the reaction that occurs as the active rods move. A difficulty in simulations of the continuum model is incorporating the molecular-scale reactions into a mesoscale approach. By addressing these challenges, the utility and applicability of these computational methods will be significantly expanded, allowing them to be used for simulating a broad range of multi-component, dynamical systems.