RUI: Stabilization of Gold Nanoparticles in Solution by Poly(Vinyl Alcohol) Adsorption

聚合物吸附到纳米颗粒上具有技术相关性和科学意义。 考虑到涉及金纳米颗粒（AuNPs）的广泛应用以及聚（乙烯醇）（PVOH）的无毒性和水溶性，令人惊讶的是，文献中尚未报道PVOH到AuNPs上的吸附研究。 选择PVOH的另一个理由是，它是可商购的，具有不同的分子量和水解程度，即不同量的残留聚（乙酸乙烯酯）（PVA）重复单元。 PVOH和PVA段的吸附到金纳米粒子上制备的普通柠檬酸盐还原法，预计将分别由氢键和疏水相互作用驱动。相互作用的主导模式将取决于给定系统中两个过程的相对能量。 聚合物组成为吸附提供了额外的控制参数，并增加了探测吸附机制的复杂性。了解PVOH/PVA吸附到AuNP上的变体，例如聚合物分子量、纳米颗粒的尺寸、聚合物组成、聚合物浓度和吸附时间，将使我们能够提出一种稳健的方法来赋予AuNP对溶液pH值、离子强度和温度变化的稳定性。对于我们的长期利益，制备自组装纳米粒子在聚合物薄膜，PVOH可能是太结晶的功能作为一个适当的聚合物基质的颗粒，形成有组织的阵列和PVA可能是重要的，在提供？柔软吗以允许粒子在自组装中移动。在AuNP-PVOH系统中开发的理解和方法可能扩展到其他纳米颗粒-亲水性聚合物缀合物。非技术概述纳米颗粒由于其高的表面积-体积比而具有在溶液中形成聚集体的趋势，导致其独特的纳米级特征的损失。将薄聚合物层吸附到纳米颗粒上是在其应用中提供颗粒稳定性的有效方法。在拟议的工作中，一种水溶性和无毒的聚合物，聚乙烯醇，将从水溶液中吸附到金纳米粒子表面上，以防止纳米粒子在pH值，离子强度和温度的环境扰动下聚集。本提案中要求的资金将支持PI？在接下来的三年里，她将与霍利奥克山学院的本科生和当地的女高中生进行研究合作。本科生和当地女高中生将参与本提案所述工作的各个方面，从设计和合成到使用常规和复杂仪器进行表征。在这个过程中，研究人员将被引入到聚合物化学的跨学科领域，并接触到纳米技术的至关重要的领域。本科生接触研究对教育和招聘都很重要。 拟议的外联活动？让当地的女高中生参与前沿研究，让当地的中学生参与有趣和有启发性的聚合物研讨会？将激励和培养更多的女性成为未来的科学家和工程师。

TECHNICAL SUMMARYPolymer adsorption onto nanoparticles has both technological relevance and scientific significance. Considering the broad range of applications involving gold nanoparticles (AuNPs) and the nontoxicity and water solubility of poly(vinyl alcohol) (PVOH), it is surprising that adsorption studies of PVOH onto AuNPs have not been reported in the literature. An additional rationale for selecting PVOH is that it is commercially available with different molecular weights and extents of hydrolysis, i.e. different amounts of residual poly(vinyl acetate) (PVA) repeat units. The adsorption of PVOH and PVA segments onto AuNPs prepared by the common citrate reduction method is expected to be driven by hydrogen bonding and hydrophobic interactions, respectively. The dominant mode of interaction will depend on the relative energetics of the two processes in a given system. Polymer composition provides an additional control parameter for adsorption and increases the complexity of probing of the adsorption mechanism(s). Understanding the variants of PVOH/PVA adsorption onto AuNPs, such as polymer molecular weight, size of nanoparticles, polymer composition, polymer concentration, and adsorption time, will allow us to propose a robust method to impart the stabilization of AuNPs against variations in solution pH, ionic strength, and temperature. For our long-term interest of preparing self-assembled NPs in polymer thin films, PVOH may be too crystalline to function as an appropriate polymer matrix for particles to form organized arrays and PVA could be important in providing ?softness? to allow particle mobility in self-assembly. The understanding and methodologies developed in the AuNP-PVOH system are potentially extendable to other nanoparticle-hydrophilic polymer conjugates.NON-TECHNICAL SUMMARYNanoparticles have the tendency to form aggregates in solution, due to their high surface area-to-volume ratio, resulting in the loss of their unique nanoscopic characteristics. Adsorption of a thin polymer layer onto nanoparticles is an effective approach to provide particle stabilization in their applications. In the proposed work, a water-soluble and nontoxic polymer, poly(vinyl alcohol), will be adsorbed onto gold nanoparticle surfaces from aqueous solutions, to prevent nanoparticles from aggregating in response to environmental perturbations in pH, ionic strength, and temperature. The funds requested in this proposal will support the PI?s efforts in research collaborations with undergraduate students at Mount Holyoke College and local female high school students over the next three years. The undergraduate and local female high school students will be involved in all aspects of the work described in this proposal, from design and synthesis to characterization using both routine and sophisticated instrumentation. In the process, researchers will be introduced to the interdisciplinary field of polymer chemistry and be exposed to the vitally important area of nanotechnology. Exposure of undergraduate students to research is important for both education and recruitment purposes. The outreach activities proposed ? having local female high school students involved in frontier research and local middle school students engaged in fun and enlightening polymer workshops ? will inspire and prepare more women to be future scientists and engineers.