CAREER: Enabling the Design of Versatile Hybrid Materials using Polymerization-Induced Nanostructural Transitions

第1部分：非技术总结同时最大化对比材料的性能，如韧性和弹性系数，这对单组分材料来说是一项艰巨的挑战。生物学能够通过层次化地组织具有不同物理性质的多个组分(生物聚合物和矿物)来偏离单一组分材料的固有限制。生物材料的静态结构和等级顺序只是故事的一部分；生物和生命系统通过非平衡过程创造复杂的材料。该职业计划的目标是研究非平衡化学功能化和自组装方法，以创建多功能聚合物/无机杂化材料。将探索两种聚合物/纳米颗粒材料系统：1)柔性和导电的共连续网络；2)表现出特殊应变强化机械性能的纳米结构材料。将非平衡化学过程建立和集成到材料设计中，可能会导致新材料在基础设施、交通、医疗保健和信息处理方面的应用。该提案的研究目标将通过以下方式整合到教学方法中：1)为宾夕法尼亚州非博士授予机构的教授开发聚合物/材料科学模块和实验室，以补充本科课程；2)为所有感兴趣的研究人员创建开放访问的视频标准操作程序(VSOP)，以学习聚合物合成、样品制备和表征的详细方法。第二部分：技术综述聚合物/无机材料杂化领域一直在假设平衡概念将导致自然界中看到的复杂材料，但生物学利用非平衡过程来创造生物材料。该提案的总体目标是确定设计标准，使用非平衡化学官能化和自组装方法，通过聚合诱导的纳米结构转变来创建多功能杂化聚合物/无机材料。在这项研究中，由附着在纳米颗粒表面的聚合物原位接枝和原位嵌段合成聚合物的方法将被用来创建柔性和导电的共连续网络和表现出应变硬化特性的纳米结构材料。这里使用的合成方法将促进复杂的聚合物结构的原位形成，并将生成具有层次化有序的材料，其中聚合物和纳米粒子的结构域从纳米到微米级组织。利用X射线和中子散射、振荡剪切动态力学谱和介电弛豫谱等表征方法将揭示聚合过程中的自组装机制，并为设计层次化有序材料提供基本的见解。将原位聚合和结构表征相结合来研究结构-性质关系，将在非平衡加工中建立基础科学，模拟自然系统并利用同时性质组合，这是目前在聚合物/无机杂化材料中不可能实现的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Part 1: NON-TECHNICAL SUMMARYAchieving simultaneous maximization of contrasting materials properties such as toughness and modulus is a daunting challenge for single-component materials. Biology is able to diverge from the inherent limitations of single-component materials by hierarchically organizing multiple components (biopolymers and minerals) with disparate physical properties. The static structure and hierarchical order of biomaterials is only part of the story; biology and living systems create complex materials through nonequilibrium processes. The goal of the CAREER proposal is to investigate nonequilibrium chemical functionalization and self-assembly methods to create multifunctional hybrid polymeric/inorganic materials. Two polymer/nanoparticle material systems will be explored: 1) flexible and electrically conductive co-continuous networks and 2) nanostructured materials exhibiting exceptional strain-stiffening mechanical properties. Establishing and integrating nonequilibrium chemical processes into materials design will potentially lead to new materials with applications in infrastructure, transportation, health care, and information processing. The research aims of the proposal will be integrated into teaching methods by: 1) developing polymer/materials science modules and labs for professors at nondoctorate-granting institutions within Pennsylvania to augment the undergraduate curriculum and 2) creating open-access video-standard operating procedures (VSOP) for all interested researchers to learn detailed methods for polymer synthesis, sample preparation, and characterization.Part 2: TECHNICAL SUMMARYThe hybrid polymer/inorganic materials field has been working under the premise that equilibrium concepts will lead to the complex materials seen in nature, yet biology utilizes nonequilibrium processes to create biomaterials. The overarching aim of the proposal is to identify design criteria using nonequilibrium chemical functionalization and self-assembly methods to create multifunctional hybrid polymeric/inorganic materials via polymerization-induced nanostructural transitions. In this research, in-situ polymer grafting and in-situ block polymer synthetic methods from polymers attached to nanoparticle surfaces will be used to create flexible and electrically conductive co-continuous networks and nanostructured materials exhibiting strain-stiffening properties. The synthetic approach used here will facilitate complex polymer architecture formation in situ and will generate hierarchically ordered materials in which polymer and nanoparticle domains are organized from the nanometer to the micrometer scale. Characterization methods using X-ray and neutron scattering, oscillatory shear dynamic mechanical spectroscopy, and dielectric relaxation spectroscopy during polymerization will reveal the self-assembly mechanism, and lead to fundamental insight for designing hierarchically-ordered materials. Merging in-situ polymerization and structural characterization to investigate structure-property relationships will establish foundational science in nonequilibrium processing that mimics natural systems and harnesses simultaneous property combinations, which are not currently possible in hybrid polymer/inorganic materials.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.