NIRT: Nanomolecular Interactions of Novel Biological and Synthetic Polyelectrolyte Brushes

在这项研究计划中，一个跨学科的研究团队已经成立，其中包括代表3所大学5个不同学术部门的4名PI，他们在科学和工程领域的广泛互补方面拥有专业知识。本研究计划的总体目标是使用强大的新型纳米尺度实验和理论工具和方法，为新型技术重要的聚电解质（PE）电刷和类电刷系统的基础物理学奠定基础。这个提议的一个独特之处在于，它融合了历史上基本上是孤立的领域，即合成和生物PE。该建议包括3个具体目标，包括：1)结结组织聚电解质的纳米力学和纳米结构研究，II)合成聚乙烯电刷梯度和纳米尺度物体的合成和纳米尺度相互作用，以及III)多尺度理论方法，可以利用原子尺度和粗粒度模型的分子动力学（MD）模拟，弥合从原子到宏观可观察量的长度尺度差距，分子理论，和基于纳米尺度连续泊松-玻尔兹曼的EDL模拟。所研究的模型PE体系有软骨糖胺聚糖（生物）和聚丙烯酸（PAA）、聚二甲氨基乙基甲基酸酯（PDMAEMA）和聚n -异丙基丙烯酰胺（PNIPAAm）（合成）。聚电解质是技术上重要的聚合物类别，用于各种应用，包括：胶体分散稳定性和流变性，环境敏感和刺激反应膜，药物输送，以及用于控制润滑和润湿性的工程表面。尽管人们对带电聚合物的兴趣持续了50多年，但人们对其独特的性质仍然知之甚少，这主要是因为直到最近，在接近生理的环境条件下直接在纳米尺度上研究这种系统所需的实验和理论方法还不存在。本研究采用强大的新型纳米技术，将能够成像、测量和预测模型生物和合成聚电解质内部和之间的纳米级相互作用力，并结合一种新的多尺度理论方法，将为这些系统提供基本的理解。这些结果将对今后了解软骨、它的强度以及它的基本力学和化学性质具有重要意义。教育和推广活动包括与K-12教师协调开发示范模块，与K-12学生和教师互动，以及将本科生作为研究人员纳入项目。

In this research proposal, an interdisciplinary research team has been assembled that includes 4 PI's representing 5 different academic departments at 3 universities who have expertise in a broad complementary array of fields of science and engineering. The overall goal of this research prrposal is to use powerful new nanoscale experimental and theoretical tolls and methodologies to deleop a foundation for the fundamental physics of novel technologically important polyelectrolyte (PE) brush and brusk-like systems. One unique aspect of this proposal is the merging of what have historically been largely isolated fields, that of synthetic and biological PE's. The proposal includes 3 specific aims including: 1) nanomechanical and nanostructural investigations of connective tissue polyelectrolytes, II) synthesis and nanoscale interactions of synthetic PE brush gradients and nanoscale objects, and III) a multiscale theoretical approach that will enable bridging the gap of length scales from the atomistic to macroscopic observable quantities using molecular dynamics (MD) simulations both at the atomistic scale and using coarse grained models, molecular theory, and nanoscale continuum Poisson-Boltzmann-based EDL simulations. The model PE systems to be studied are cartilage glycosaminoglycans (Biological) and polyacrylic acid (PAA), poly(dimethylaminoethyl metharylate) (PDMAEMA), and poly(N-isopropyl acrylamide) (PNIPAAm) (synthetic). Polyelectrolytes are technologically important classes of polymers used in a wide variety of applications including: colloidal dispersion stabilization and rheology, environmentally sensitive and stimulus-responsive membranes, drug delivery, and engineered surfaces for control of lubrication and wettability. Despite more than 50 years of continuing interest, the unique properties of charged polymers are still poorly understood, mostly due to the fact that up until recently, experimental and theoretical methods needed to study such systems directly at the nanoscale in near-physiological environmental conditions did not exist. The proposed research using powerful new nanotechnological techniques will enable the imaging, measurement, and prediction of nanoscale interaction forces within and between model biological and synthetic polyelectrolytes and combined with a novel multiscale theoretical approach will provide fundamental understanding of such systems. The results will be important for future understanding of cartilage, its strength, and its fundamental mechanical and chemical properties. Educational and outreach activities include coordination with K-12 teachers in developing demonstration modules, interaction with K-12 students and teachers, and incorporation of undergraduate students as researchers in the project.