Inhibition of Water Crystallization by 3D Confinement in Supramolecular Hydrogels

1606685 PI：沃格特，布赖恩标题：水是维持生命的关键，但它仍然是一个谜，充分了解其性质。它的热力学是高度反常的多个固态相，包括几个非晶态。当被限制在小空间时，水表现出不同的热力学状态，包括结晶阻力。类似地，蛋白质的功能是通过调节水的水合作用和局部结构来驱动的，这可以抑制冰结晶，但合成类似物一直难以实现。该提案的主要思想是，通过疏水缔合交联的水凝胶是模拟自然系统的受限水的良好模型。拟议的研究将采用超分子水凝胶，通过疏水缔合交联，作为模型来研究限制下的水动力学，比多孔无机物更好地模拟自然系统。工作假设是，纳米疏水域，在足够的浓度，可以限制水产生过冷水与快速动态。该研究解决了过冷水物理学中的基本问题，这可能解决水凝胶低温使用中的问题（例如，具有动态交联的超分子水凝胶通过疏水纳米结构域在二甲基丙烯酰胺（一种水溶性单体）和2-N-乙基全氟辛烷磺酰胺乙基丙烯酸酯（一种疏水单体）的共聚物中的自组装形成，表现出具有小于15 nm的亲水区域分隔疏水纳米结构域的明确的纳米结构。 可以改变共聚物组成以定制水限制的长度尺度。该项目的重点是理解和控制水凝胶中过冷水的动力学。拟议的研究旨在1）了解水凝胶的结构如何与抑制冰形成相关，2）确定亲水聚合物对过冷效率的影响，3）开发结构-性能关系，以描述和预测超分子水凝胶中水状态的分布作为化学和组成的函数。将采用各种复杂的表征工具来研究水的冻结热力学和动力学。除了培养研究生外，PI还计划让本科生和高中生参与跨学科研究项目，并招募少数民族学生进入STEM职业。拟议的外展活动将包括与当地K-12学生进行水凝胶和水性质的实践演示和讨论，以及与阿克伦全球聚合物学院合作分发冰形成和水凝胶的视频。

1606685 PI: Vogt, Bryan Title: Inhibition of Water Crystallization by 3D Confinement in Supramolecular Hydrogels Water is critical for sustaining life, yet it still remains a puzzle with regard to full understanding of its properties. Its thermodynamics is highly anomalous with multiple solid-state phases including several amorphous states. When confined to small spaces, water exhibits different thermodynamic states, including a resistance to crystallization. Similarly, the function of proteins is driven by modulation of the hydration and structure of water locally, which can inhibit ice crystallization, but synthetic analogs have been challenging to achieve. The main idea of this proposal is that a hydrogel crosslinked by hydrophobic associations is a good model of water under confinement that mimics natural systems. The proposed research will employ a supramolecular hydrogel, crosslinked by hydrophobic associations, as a model to study the dynamics of water under confinement that better mimics natural systems than porous inorganics. The working hypothesis is that the nanoscale hydrophobic domains, at sufficient concentration, can confine water to yield supercooled water with fast dynamics. The research addresses fundamental questions in the physics of supercooled water, which may solve problems in the low temperature use of hydrogels (e.g., fracture when water expands upon freezing), an important commercial technology.Supramolecular hydrogels with dynamic crosslinks formed by self-assembly of hydrophobic nanodomains in copolymers of dimethyl acrylamide, a water soluble monomer, and 2-N-ethylperfluorooctane sulfonamidoethyl acrylate, a hydrophobic monomer, exhibit a well-defined nanostructure with smaller than 15 nm hydrophilic regions separating the hydrophobic nanodomains. The copolymer composition can be varied to tailor the length scale of water confinement. This proposed project focuses on understanding and controlling the dynamics of supercooled water in hydrogels. The proposed research seeks to 1) understand how the structure of hydrogels correlates with suppressed ice formation, 2) determine the effect of the hydrophilic polymer on supercooling efficacy, and 3) develop structure-property relationships to describe and predict the distribution of water states within supramolecular hydrogels as a function of chemistry and composition. A wide array of sophisticated characterization tools will be employed to study freezing thermodynamics and dynamics of water. In addition to training graduate students, the PIs plan to engage undergraduate and high school students in interdisciplinary research projects and recruit minority students into STEM careers. Proposed outreach activities will include hands-on demonstrations and discussions of hydrogels and water properties with local K-12 students and distribution of videos of ice formation and hydrogels in collaboration with the Akron Global Polymer Academy.