Novel Mixed Brushes with Tunable Internal Structures of Various Length Scales

具有各种长度尺度可调内部结构的新型混合刷

• 批准号: 0906567
• 负责人: You-Yeon Won
• 金额: $ 44.8万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906567&HistoricalAwards=false
• 关键词: Novel; Mixed; Brushes; Tunable; Internal

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY:Using a combined experimental and theoretical approach, the proposed research aims to provide fundamental understanding of the thermodynamics of novel mixed polymer brush systems, namely, the mixed brushes composed of laterally-mobile, weak polyelectrolyte and neutral polymer chains that are mutually incompatible. This novel mixed brush system offers previously unavailable opportunities (i) to produce mesoscopic surface patterns of various length scales by long-range-frustrated lateral phase separation between the two chain types and (ii) to create functional interfaces with surface properties switchable between charged and non-charged states. These properties, achievable only with this unique combination of ionizable and neutral polymers with laterally-mobile grafting points, have enormous potential to be used for advanced technological purposes in such areas as (i) functional surface patterning for advanced fabrication of two-dimensional nano/microstructures and (ii) biomedical delivery and detection. Understanding of the thermodynamics that governs the behavior of the mixed brushes is essential to furthering the development of these technological applications. The specific objectives of this research are to establish and understand the key thermodynamic properties, including (a) two-dimensional phase behavior, (b) phase-separated domain structures, (c) lateral brush compressibility and (d) chain conformations, of a model mixed brush system constructed using mixed diblock copolymers at the air-water interface. This mixed brush system will be studied using combined experimental techniques of fluorescence/AFM imaging, pressure-area isotherm and neutron/x-ray reflectivity measurements, to establish how the brush molecular characteristics (i.e., polymer molecular weights, brush composition, and chain grafting density) and the solution electrostatic environment (i.e., pH and ionic strength of the medium) influence the above-mentioned properties of the mixed brush system. These experimental investigations will be complemented by self-consistent field (SCF) theoretical studies to establish a consistent and theoretically sound understanding of the experimental results.NON-TECHNICAL SUMMARY:The intellectual merit of the proposed research is that, by using a unique combination of experiment and theory, this research will provide a useful understanding of the phase behavior and structures of this new class of mixed polyelectrolyte brush system. The knowledge gained from this research will also have great implications for developing a generalized understanding of the ?frustrated phase separation? phenomena widely observed in various materials ranging from biological cell membranes to two-dimensional electronic systems. The broader impacts of the proposed activities are far reaching. Formulating the surface of a material with a mixed polyelectrolyte and neutral polymer brush represents a new paradigm applicable, as a generic methodology, to a wide variety of advanced technologies, including nano/micro fabrication and biomedical technologies, and the proposed research will provide the fundamental materials science groundwork necessary for further technological development in these areas. The proposed research will provide integrated training for graduate and undergraduate students in a multidisciplinary, collaborative and intellectually stimulating environment to learn skills necessary for the future generation of polymer/soft materials scientists. Aspects of the proposed research will be used to enhance curricula in the areas of polymers and nanomedicine.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。技术摘要：采用实验和理论相结合的方法，拟议的研究旨在提供新的混合聚合物刷系统的热力学的基本理解，即，由横向移动的，弱极性和中性的聚合物链是相互不相容的混合刷。这种新型的混合刷系统提供了以前不可用的机会（i）产生各种长度尺度的介观表面图案的两种链类型之间的长程受阻的横向相分离和（ii）创建功能界面与带电和非带电状态之间的表面特性可切换。这些性能，可实现只有与这种独特的组合的电离和中性聚合物与横向移动的接枝点，具有巨大的潜力，用于先进的技术目的，在这些领域，如（i）功能表面图案化先进的制造二维纳米/微结构和（ii）生物医学的交付和检测。了解控制混合刷行为的热力学对于进一步发展这些技术应用是必不可少的。本研究的具体目标是建立和理解关键的热力学性质，包括（a）二维相行为，（B）相分离域结构，（c）侧刷压缩性和（d）链构象，在空气-水界面上的模型混合刷系统使用混合二嵌段共聚物。将使用荧光/AFM成像、压力面积等温线和中子/X射线反射率测量的组合实验技术来研究这种混合刷系统，以建立刷分子特性（即，聚合物分子量、刷组成和链接枝密度）和溶液静电环境（即，介质的pH和离子强度）影响混合刷体系的上述性质。这些实验研究将补充自洽场（SCF）的理论研究，以建立一个一致的和理论上合理的理解的实验结果。非技术摘要：拟议的研究的智力价值是，通过使用一个独特的实验和理论相结合，这项研究将提供一个有用的理解这一类新的混合电刷系统的相行为和结构。从这项研究中获得的知识也将有很大的影响，发展一个普遍的理解？受挫折的相分离？在从生物细胞膜到二维电子系统的各种材料中广泛观察到的现象。拟议活动的广泛影响是深远的。用混合的中性聚合物刷配制材料表面代表了一种新的范式，作为一种通用方法，适用于各种先进技术，包括纳米/微米制造和生物医学技术，拟议的研究将为这些领域的进一步技术发展提供必要的基本材料科学基础。拟议的研究将为研究生和本科生提供综合培训，在多学科，协作和智力刺激的环境中学习未来一代聚合物/软材料科学家所需的技能。拟议研究的各个方面将用于加强聚合物和纳米医学领域的课程。