The Role of Grafting Mechanism on the Self-Assembly and Properties of Polymer Nanocomposites

接枝机制对聚合物纳米复合材料自组装和性能的作用

• 批准号: 1709061
• 负责人: Sanat Kumar
• 金额: $ 59.2万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1709061&HistoricalAwards=false
• 关键词: Role; Grafting; Mechanism; Self; Assembly

NON-TECHNICAL SUMMARY: The addition of inorganic nanoparticles (NPs) to a polymer (i.e. a plastic material) can result in hybrid materials with highly improved properties. A classic example is that, while rubber (as e.g. in an eraser) has extremely poor wear resistance, the addition of silica nanoparticles causes the wear resistance to go up so much that a car can drive with tires that last over 50,000 miles. While such property improvements are what drive developments in the field of polymer nanocomposites, the inherent problem is that the nanoparticles are chemically so different from the polymer (a hydrocarbon material) and thus have a strong tendency to separate from each other akin to a water-oil suspension. Thus, the desirable, favorable property improvements that can only be realized by the intimate mixing of the polymer and the NPs become hard to realize on a routine basis. The work here proposes to remedy this problem by chemically grafting polymer chains onto the NPs so that the inorganic particle surface can be "shielded" from the polymer, thus allowing miscibility to be obtained. In particular, the work focuses on two strategies for this grafting: either grafting fully formed chains to the surfaces, or growing the chains piece-by-piece from the surface. Which of these strategies allows better control over particle-polymer miscibility and therefore improve properties the most is the focus of this research. In addition to this technical emphasis, the proposed work will also stress the broad, interdisciplinary education of students and the recruitment and retention of women and minority students into STEM programs by attracting high-school and undergraduate students into engineering research activities in the PI's laboratory.TECHNICAL SUMMARY: The focus of this proposal is on the self-assembly of polymer-grafted nanoparticles (NPs) in a polymer matrix with the goal of impacting the behavior of the resulting hybrid (or composite) material. This physical situation has relevance to improved performance in, for example, rubber tires and epoxies (which are used in electronic packaging and computer chip applications). This underpinning question will be studied through the exploration of three test-beds by judiciously combining theory and experiments. In particular, emphasis will be placed on role of the mechanism by which chains are grafted onto NP surfaces on the final material properties, i.e., whether the chains are preformed and attached to the surface or if the chains are grown link-by-link from the surface. It is expected that the former mechanism will yield a more uniform polymer coverage on the NP surface. The consequence of these differences in surface coverage on the assemblies formed and the resulting properties is the ultimate focus of this work. These research activities are coupled to extensive education and outreach activities. A major focus will be to recruit underrepresented students (both women and minorities) at both the undergraduate and graduate levels. It is planned to grow both the current summer high-school research program, and also the research-experiences-for-undergraduates program during the schoolyear, with the goal of recruiting (and hopefully retaining) women and minorities into STEM efforts.

非技术摘要：将无机纳米颗粒 (NP) 添加到聚合物（即塑料材料）中可以产生具有高度改进性能的混合材料。一个典型的例子是，虽然橡胶（例如橡皮擦中的橡胶）的耐磨性极差，但添加二氧化硅纳米颗粒会导致耐磨性大幅提高，以至于汽车的轮胎可以行驶超过 50,000 英里。 虽然这种性能的改进推动了聚合物纳米复合材料领域的发展，但固有的问题是纳米颗粒在化学上与聚合物（碳氢化合物材料）非常不同，因此具有很强的相互分离的倾向，类似于水油悬浮液。因此，只能通过聚合物和纳米颗粒的紧密混合才能实现的理想的、有利的性能改进在常规基础上变得难以实现。这里的工作建议通过将聚合物链化学接枝到纳米颗粒上来解决这个问题，这样无机颗粒表面就可以“屏蔽”聚合物，从而获得混溶性。特别是，这项工作重点关注这种嫁接的两种策略：要么将完全形成的链嫁接到表面，要么从表面逐段生长链。这些策略中哪一种可以更好地控制颗粒-聚合物的混溶性，从而最大程度地改善性能是本研究的重点。 除了这一技术重点外，拟议的工作还将强调对学生进行广泛的跨学科教育，并通过吸引高中生和本科生参与 PI 实验室的工程研究活动，招募和保留女性和少数民族学生进入 STEM 项目。 技术摘要：该提案的重点是聚合物基体中聚合物接枝纳米颗粒 (NP) 的自组装，其目标是 影响所得混合（或复合）材料的行为。这种物理情况与橡胶轮胎和环氧树脂（用于电子封装和计算机芯片应用）等性能的提高有关。我们将通过明智地结合理论和实验，通过对三个试验台的探索来研究这个基础问题。特别是，重点将放在链接枝到纳米粒子表面的机制对最终材料性能的影响，即链是否预先形成并附着到表面，或者链是否从表面逐个链接地生长。预计前一种机制将在纳米颗粒表面产生更均匀的聚合物覆盖。形成的组件表面覆盖度的这些差异以及由此产生的性能是这项工作的最终焦点。这些研究活动与广泛的教育和推广活动相结合。主要重点是在本科生和研究生阶段招收代表性不足的学生（包括女性和少数民族）。 计划在学年期间发展当前的夏季高中研究计划以及本科生研究经验计划，目标是招募（并希望留住）女性和少数族裔参与 STEM 工作。

项目成果

Detecting bound polymer layers in attractive polymer–nanoparticle hybrids

检测有吸引力的聚合物与纳米颗粒混合物中的结合聚合物层

• DOI: 10.1039/d1nr02395k
• 发表时间: 2021
• 期刊: Nanoscale
• 影响因子: 6.7
• 作者: Emamy, Hamed;Starr, Francis W.;Kumar, Sanat K.
• 通讯作者: Kumar, Sanat K.

Assembly of Polymer-Grafted Nanoparticles in Polymer Matrices

• DOI: 10.1021/acsnano.0c05495
• 发表时间: 2020-10-27
• 期刊: ACS NANO
• 影响因子: 17.1
• 作者: Koh, Clement;Grest, Gary S.;Kumar, Sanat K.
• 通讯作者: Kumar, Sanat K.

Role of Grafting Mechanism on the Polymer Coverage and Self-Assembly of Hairy Nanoparticles

• DOI: 10.1021/acsnano.7b02657
• 发表时间: 2017-07-01
• 期刊: ACS NANO
• 影响因子: 17.1
• 作者: Asai, Makoto;Zhao, Dan;Kumar, Sanat K.
• 通讯作者: Kumar, Sanat K.

Impact of the Distributions of Core Size and Grafting Density on the Self-Assembly of Polymer Grafted Nanoparticles

• DOI: 10.1021/acs.macromol.7b01093
• 发表时间: 2017-10-10
• 期刊: MACROMOLECULES
• 影响因子: 5.5
• 作者: Bachhar, Nirmalya;Jiao, Yang;Kumar, Sanat K.
• 通讯作者: Kumar, Sanat K.

Morphologies of Polyisoprene-Grafted Silica Nanoparticles in Model Elastomers

模型弹性体中聚异戊二烯接枝二氧化硅纳米颗粒的形貌

• DOI: 10.1021/acs.macromol.9b01479
• 发表时间: 2019
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Bonnevide, Marine;Jimenez, Andrew M.;Dhara, Deboleena;Phan, Trang N.T.;Malicki, Nicolas;Abbas, Zaid M.;Benicewicz, Brian;Kumar, Sanat K.;Couty, Marc;Gigmes, Didier
• 通讯作者: Gigmes, Didier