Collaborative research: Rates and Mechanisms of Biofouling and Mineral Scaling on Zwitterionic Amphiphilic Copolymer Surfaces

化学系环境化学科学项目的这一奖项支持塔夫茨大学的艾塞·阿萨特金教授以及休斯顿大学的胡燕迪和德博拉·罗德里格斯教授研究矿物结垢和生物结垢的机制，这些机制以前被证明具有很好的抗有机污染能力。污垢或不需要的材料在表面上的沉积在许多应用中是一个严重的问题，其中表面与海水接触，影响船体、热交换器和膜。因此，迫切需要开发当暴露于各种环境流时抗结垢的材料。结垢可由水中各种组分的沉积引起，包括有机化合物、微生物或无机矿物质。该项目的重点是一个新的家庭的材料具有特殊的抗有机污垢。这项研究的主要目的是确定这些材料是否也能抵抗生物污垢（即微生物的粘附）和矿物结垢（即无机盐或矿物的沉积），了解它们的化学结构如何影响这些不同类型的污垢过程，并最终开发出抵抗多种类型污垢的表面设计规则。这项研究是由一个多元化的研究生和本科生团队在实验室进行的，他们在招募和培训代表性不足的群体成员方面有着良好的记录，并被纳入了几个大学课程和针对女孩和代表性不足的少数民族的K-12外联活动。该项目研究了两性离子和疏水单体的两亲性共聚物（称为两性离子两亲性共聚物（ZAC））的生物污垢和矿物结垢过程，该共聚物可以对有机污垢表现出前所未有的抵抗力。该团队正在合成具有一系列单体化学，疏水性和表面电荷的ZAC。在涂覆到基材上时，筛选这些材料的有机污垢抗性。有前途的ZAC的石膏结垢和生物污垢的机制和速率方面进行了调查。缩放研究采用最先进的技术，在原位定量的石膏矿物表面上的异质成核，以及它们的聚集和沉积。该项目还开发了一种定量PCR阵列方法来识别ZAC涂层表面上生物污垢的微生物遗传途径。与此同时，先进的显微技术被用来识别ZAC的独特特性，并将它们与初始微生物细胞附着率和生物膜生长率联系起来。还考虑了生物污损和结垢的协同效应。这些结果与ZAC化学（两性离子和疏水基团），表面能，表面电荷和其他标准进行了编译和相关。这项工作预计将导致一个基本的了解机制和ZAC表面化学性质相关的有机污垢，生物污垢，结垢。该团队的多学科和互补的专业知识使新型先进材料的合理设计成为可能，从而在环境化学，化学和环境工程，环境微生物学和材料科学等学科中获得新的科学和变革性发现。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

This award from the Environmental Chemical Sciences Program in the Division of Chemistry supports Professors Ayse Asatekin from Tufts University, and Yandi Hu and Debora Rodrigues from University of Houston to investigate mechanisms of mineral scaling and biofouling on a new family of materials previously demonstrated to exhibit promising resistance to organic fouling. Fouling, or the deposition of unwanted materials on surfaces, is a severe problem in many applications where surfaces are in contact with seawater, affecting ship hulls, heat exchangers, and membranes. Therefore, there is an urgent need for developing materials that resist fouling when exposed to various environmental streams. Fouling can arise from the deposition of various components in water, including organic compounds, microorganisms, or inorganic minerals. This project focuses on a new family of materials having exceptional resistance to organic fouling. The main objective of this research is to determine if these materials also resist biofouling (i.e. adhesion of microorganisms) and mineral scaling (i.e. deposition of inorganic salts or minerals), understand how their chemical structure affects these different types of fouling processes, and eventually develop design rules for surfaces that resist multiple types of fouling. The research is conducted by a diverse team of graduate and undergraduate students in labs with a track record of recruiting and training members of underrepresented groups, and is incorporated into several university courses and K-12 outreach activities targeted at girls and underrepresented minorities. This project investigates processes of biofouling and mineral scaling on amphiphilic copolymers of zwitterionic and hydrophobic monomers, termed zwitterionic amphiphilic copolymers (ZACs), which can exhibit unprecedented resistance to organic fouling. The team is synthesizing ZACs with a range of monomer chemistries, hydrophobicities, and surface charges. Upon coating onto substrates, these materials are screened for organic fouling resistance. Promising ZACs are investigated in terms of the mechanisms and rates of gypsum scaling and biofouling. Scaling studies employ state-of-the-art techniques for in situ quantification of the heterogeneous nucleation of gypsum minerals onto surfaces as well as their aggregation and deposition. This project also develops a quantitative PCR array approach to identify the microbial genetic pathways of biofouling on ZAC coated surfaces. At the same time, advanced microscopic techniques are used to identify the unique properties of ZACs and connect them with initial microbial cell attachment rates and biofilm growth rates. Synergistic effects of biofouling and scaling are also considered. These results are compiled and correlated with ZAC chemistry (zwitterionic and hydrophobic groups), surface energy, surface charge, and other criteria. This work is expected to lead to a fundamental understanding of mechanisms and ZAC surface chemistry properties associated to organic fouling, biofouling, and scaling. The team's multidisciplinary and complementary expertise enables rational design of novel advanced materials to allow new scientific and transformative findings across disciplines of environmental chemistry, chemical and environmental engineering, environmental microbiology, and materials science.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.