CAREER: Stereochemical Biomimicry for Sustainability

该学院早期职业发展（CAREER）奖解决了建筑材料技术中的一个紧迫问题，即设计具有低缺陷敏感性和高长期结构完整性的耐用胶凝材料。我们建筑环境的功能性和弹性在很大程度上取决于混凝土的性能，混凝土是一种在实际应用中广泛采用的材料。然而，混凝土中大量的微观结构缺陷和环境的催化因素降低了现有技术对抗裂缝成核和生长的有效性。因此，混凝土结构的耐久性和寿命不断受到挑战。该项目将使立体化学仿生途径，通过强大的有机-无机纳米添加剂和水泥基复合材料的创建。受自然界的启发，这项研究将短链有机分子与无机硅酸钙水合物（C-S-H）偶联，以减少混凝土的拉伸和压缩强度之间的差距，实现上级韧性，并降低固有的孔隙率和材料渗透性。该研究与化学，生物分子和计算材料科学家合作，采用最先进的实验方法，发现具有增强或新颖物理和化学性质的杂化材料的新合成工艺，并促进工程科学的进步。包容性的科学传播和循证推广活动将吸引所有年龄段的观众，从K-12学生和本科生到美国退伍军人，特别是属于历史上弱势群体的人，准备他们参加未来的STEM劳动力能够满足新兴的技术挑战。它是建立生物体使用有机分子和立体化学识别制造复杂的材料，其特征在于通过强大的物理化学和机械性能。受这一过程的启发，本研究的目标是揭示控制短链功能化有机分子与C-S-H之间相互作用的立体化学仿生原理。计算和实验相结合的方法将测试以下中心假设：界面的立体化学效应决定了纳米粒子的成核，生长和自组装路径在反应性胶体水泥系统。因此，该奖项解决了三个领域的知识差距：（a）C-S-H和有机分子之间的立体结构和能量结合基序的解析;（B）理解与有机改性剂的分子结构相关的调节C-S-H成核、生长和织构稳定的分子尺度机制、热力学和动力学控制变量;（c）发现了C-S-H自组装的立体化学途径。解决这些知识差距将允许合理设计与C-S-H有针对性的相互作用的改性剂，以及降低缺陷敏感性的工程仿生混凝土，从而提高韧性和长期结构完整性。该项目将使PI能够推进材料科学，胶体物理和化学的知识基础，并建立他在基础设施材料工程仿生方面的长期职业生涯。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，被认为值得支持。

This Faculty Early Career Development (CAREER) award addresses a pressing issue in construction materials technology, namely the design of durable cementitious materials with low defect sensitivity and high long-term structural integrity. The functionality and resiliency of our built environment heavily depend on the performance of concrete, a widely adopted material in practical applications. However, the high population of microstructural defects in concrete and the environment's catalytic factors diminish the effectiveness of existing technologies against crack nucleation and growth. Thus, concrete structures' durability and longevity are continuously challenged. This project will enable stereochemical biomimicry pathways through which robust organic-inorganic nano additives and cementitious composites are created. Inspired by nature, this research will couple short-chain organic molecules with an inorganic calcium-silicate-hydrate (C-S-H) to reduce the disparity between concrete's tensile and compressive strength, achieve superior toughness, and decrease inherent porosity and material permeability. In partnership with chemical, biomolecular and computational materials scientists, this research resorts to state-of-the-art experimental methods to discover new synthesis processes of hybrid materials with enhanced or novel physical and chemical properties and to promote progress in engineering science. Inclusive science communication and evidence-based outreach activities will engage an audience of all ages, from K-12 students and undergraduates to U.S. Veterans, especially belonging to historically disadvantaged groups, to prepare them to participate in a future STEM workforce capable of meeting emerging technological challenges.It is established that living organisms use organic molecules and stereochemical recognition to fabricate complex materials characterized by robust physicochemical and mechanical properties. Inspired by this process, the overreaching goal of this research is to unravel the stereochemical biomimicry principles that govern interactions between short-chain functionalized organic molecules and C-S-H. The combined computational and experimental approach will test the following central hypothesis: the interfacial stereochemical effects dictate the nanoparticle nucleation, growth, and self-assembly path in reactive colloidal cement systems. Thus, this award addresses knowledge gaps in three areas: (a) the resolution of stereostructural and energetic binding motifs between the C-S-H and organic molecules; (b) understanding the molecular-scale mechanism, thermodynamic, and kinetic control variables regulating C-S-H nucleation, growth, and texture stabilization in relation to the molecular architecture of the organic modifier; and (c) discovery of stereochemical pathways of C-S-H self-assembly in confined cement environment. Resolving these knowledge gaps will allow the rational design of modifiers for targeted interaction with C-S-H, and engineering biomimetics concrete with reduced defect sensitivity, thus enhancing toughness and long-term structural integrity. This project will enable the PI to advance the knowledge base in materials science, colloids physics and chemistry and to establish his long-term career in engineering biomimetic of infrastructure 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.