GOALI - Fundamental Studies of Microstructure and Property Development in Novel Latex Coatings

知识价值：这项合作研究探索了由阿科玛公司开发的工程乳胶颗粒制成的涂料的微观结构和性能发展的基本原理。阿科玛是涂料行业专用化学品的领先供应商，并一直是新型乳胶颗粒合成路线开发的创新者。明尼苏达大学开发了先进的技术来监测干燥过程中的原位结构和性能发展，并通过时间切片方法将涂层在结构发展的不同阶段冷冻，然后通过低温扫描电子显微镜（cryoSEM）在冷冻状态下进行检查。该研究的总体目标是利用与工业相关且非常适合基础研究的模型系统，促进对乳胶漆薄膜形成和结构发展的理解。本研究将探索两种新型乳胶体系：(1)嵌段共聚物乳胶和(2)含氟聚合物丙烯酸乳胶。嵌段共聚物胶乳由微相分离纳米结构的硬、软嵌段结合的纳米结构粒子组成。这种纳米结构在薄膜形成中的作用尚不清楚。这部分研究的目的是将嵌段共聚物乳胶颗粒的纳米结构与成膜过程和涂层的最终结构联系起来。具有一系列化学和形态的嵌段共聚物乳胶模型将在阿科玛合成。低温扫描电镜将用于跟踪薄膜形成过程中结构的发展，以便与纳米结构建立连接。结构发展的各个阶段，从离散的颗粒通过压实和变形到最终的合并膜，将在冷冻标本中成像。原子力显微镜研究将补充研究。使用含氟聚合物-丙烯酸乳胶，主要目的是表征薄膜的形成，并将结构的发展与应力和开裂联系起来。了解和控制裂缝对乳胶材料的应用具有重要意义。阿科玛将提供带或不带聚结剂的模型材料。低温扫描研究将与重量损失和应力发展的测量以及开裂的观察同时进行，以确定引起开裂的应力的来源以及乳胶颗粒结构在这种现象中的作用。第二个目标是使用更广泛的颗粒集来探索颗粒和工艺参数之间的联系，并最终制定减轻裂缝的策略。更广泛的影响：这项研究将影响涂层加工、胶体科学、材料表征和颗粒力学等领域。该结果将广泛应用于其他乳胶材料，为工业上用水性乳胶涂料取代溶剂型聚合物涂料提供越来越多的努力。这项研究将有助于促进科学认识，以便公司能够在寻求改善环境时应对所面临的挑战。这项研究的影响将扩展到多个学生群体。首先，这项研究将有助于研究生和本科生研究人员的职业发展，他们将在夏季加入这项工作。这些学生不仅可以从研究中学习，还可以从与学术界和工业界科学家的互动中学习。其次，学术pi所在院系的研究生将有机会参加涉及阿科玛pi的工业圆桌会议。第三，为本科材料加工课程设计一个新的实验。学生们将设计涂料配方来制作一个凉爽的屋顶？采用含氟聚合物丙烯酸乳胶。最后，pi将开发一个学习模块，向K-12学生介绍工程概念，这是明尼苏达州最近科学标准变化的重要主题。该模块还将建立在电影形成的基本概念，并将包括一个凉爽的屋顶工程。一名高中科学老师将加入该团队，帮助研究和开发学习模块。阿科玛基金会将通过其暑期课程为科学教师提供学习模块。

Intellectual Merit: This collaborative research explores the fundamentals of microstructure and property development in coatings created from engineered latex particles developed at Arkema, Inc. Arkema is a leading supplier of specialty chemicals that are used in the coatings industry and has been an innovator in the development of synthetic routes to new latex particles. The University of Minnesota has developed advanced techniques to monitor structure and property development in situ during drying and via time sectioning methods in which the coating is frozen at different stages of structure development and then examined in the frozen state by cryogenic scanning electron microscopy (cryoSEM). The overall aim of the research is to advance the understanding of the film formation and structure development in latex coatings using model systems that are industrially relevant and well suited to fundamental research. Two novel latex systems will be explored in this research: (1) block copolymer latex and (2) fluoropolymer acrylic latex. The block copolymer latex consists of nanostructured particles with a combination of hard and soft blocks in a microphase separated nanostructure. The role of this nanostructure on film formation is not understood. The objective of this part of the research is to connect the nanostructure of block copolymer latex particles with the film formation process and the final structure of the coating. Model block copolymer latex with a range of chemistries and morphologies will be synthesized at Arkema. CryoSEM will be used to track the development of structure during film formation so that connections to nanostructure can be made. The stages in structure development, from discrete particles through compaction and deformation to the final coalesced film, will be imaged in frozen specimens. AFM studies will complement the research. With the fluoropolymer-acrylic latex, the main objective is to characterize film formation and relate the structure development to stress and cracking. Understanding and controlling cracking is important to the application of latex materials. Arkema will provide model materials formulated with and without a coalescing aid. CryoSEM studies will be carried out in parallel with measurements of weight loss and stress development and observations of cracking in order to determine the origin of the stress that causes cracking and the role of the latex particle structure on the phenomenon. The second objective is to use a broader set of particles to explore connections between particle and process parameters on cracking, and ultimately to develop strategies to mitigate cracks.Broader Impacts: This research will impact the fields of coating processing, colloidal science, materials characterization, and particle mechanics. The results will broadly apply to other latex materials, feeding a growing effort in industry to replace solvent based polymer coatings with water-based latex coatings. The research will help to advance the scientific understanding so that companies can meet the challenges they face as they seek to improve the environment. The impact of the research will extend to multiple groups of students. First, the research will help the career development of the graduate student as well as the undergraduate researchers, who will join the effort in the summers. These students will learn not only from the research itself but also from the interactions with academic and industrial scientists. Second, the graduate students in the home department of the academic PIs will have the opportunity to participate in an industrial roundtable that involves the Arkema PIs. Third, a new experiment will be designed for an undergraduate course in Materials Processing. The students will design coating formulations to make a Cool Roof? using the fluoropolymer acrylic latex. Lastly, the PIs will develop a learning module that introduces K-12 students to engineering concepts, an important topic in light of recent changes to the science standards in the State of Minnesota. The module will also be built on basic concepts in film formation and will include engineering of a Cool Roof. A high school science teacher will join the team to help with the research and the development of the learning module. The Arkema Foundation will make the learning module available through its summer program for science teachers.