Atmospheric Pressure Plasma Processing of Polymers: Plasma Dynamics and Nanoscale Plasma-Surface Interactions

项目摘要聚合物的大气压等离子体处理：等离子体动力学和纳米级等离子体表面相互作用这是一个计算研究程序，在聚合物的大气压等离子体(APP)加工的背景下，研究大气压等离子体(APP)传输和等离子体-表面相互作用的基本原理。该计划的目标是建立一个综合的、多尺度的建模体系，跨越纳米到厘米的尺度，并利用它来确定高价值材料的APP加工的极限等离子体传输过程和上行潜力。这些目标是通过开发能够研究复杂等离子体化学的大气压电晕和辉光放电的全面的三维等离子体动力学模型来实现的；开发能够解决聚合物中典型的纳米级空间结构的三维等离子体-表面相互作用算法；采用特征轮廓模型(最初是为半导体加工开发的)来解决聚合物表面上的等离子体引发的化学；并将这些模块集成到厘米到纳米的层次中。利用等离子体来产生所需的聚合物表面属性，如疏水性或亲水性，是当前科学研究和商业感兴趣的主题。实现这一功能化的途径有两条：沉积和改性。在等离子体沉积中，通过从等离子体中沉积材料来获得具有特定特性的聚合物表面。这些工艺通常在低压系统中进行，与用于微电子制造的系统没有什么不同。因此，这种加工通常仅限于高附加值材料，如生物相容性涂层。在等离子体改性中，用等离子体处理传统制造的廉价聚合物以改变其表面性质。这些过程通常是在大气压下使用电晕放电装置以“网”的形式进行的。与低压等离子体沉积不同，常压等离子体对聚合物的加工通常是一个低附加值的过程。对聚合物和塑料(如聚丙烯和聚乙烯)进行加工，以改善它们的附着力和润湿性。尽管APP用于处理聚合物的商业用途很少，但很少有一阶的、基于基础的模型来描述改性聚合物表面的等离子体-表面相互作用。因此，从所有实用目的来看，聚合物加工APP的开发和优化一直是一项经验性的承诺，因为Broader能够采用廉价和大容量的APP方法来改性聚合物以生产高价值薄膜，这对经济和社会效益的影响是惊人的。例如，用于治疗烧伤患者的生物相容性人造皮肤的生产成本为每平方米1,000美元，而美国食品和药物管理局批准的新产品的典型价格是每平方米1,000美元‘S’到10,000美元‘S。目前的知识库不足以取得这些进展，改进这一知识库将有助于确定实现这些目标的可行性。本项目中产生的计算技术和知识库的改进适用于各种APP应用，包括照明、有毒气体修复、表面消毒、生物修复和微排放。

Project SummaryAtmospheric Pressure Plasma Processing of Polymers: Plasma Dynamics and Nanoscale Plasma Surface InteractionsThis is a computational research program that investigates fundamentals of atmospheric-pressure plasma (APP) transport and plasma-surface interactions in the context of APP processing of polymers. The goals of this program are an integrated, multi-scale modeling hierarchy, spanning scales of nanometers to centimeters, and its use to determine the limiting plasma transport processes and upside potential of APP processing of high-value materials. These goals are met by developing a comprehensive, 3-dimensional plasma-dynamics model for atmospheric-pressure corona and glow discharges that is capable of investigating complex plasma chemistries; developing 3-d plasma-surface interaction algorithms capable of addressing the nanoscale spatial structures typically found on polymers; adapting feature-profile models (originally developed for semiconductor processing) to address plasma-initiated chemistry on polymer surfaces; and integrating these modules into a centimeter-to-nanometer hierarchy.The use of plasmas to produce desired surface properties of a polymer, such as hydrophobicity or hydrophilicity, is a topic both of current scientific investigation and of commercial interest. There are two pathways to achieve this functionalization: deposition and modification. In plasma deposition, polymeric surfaces with specific characteristics are obtained by depositing materials from a plasma. These processes are usually performed at low pressures in systems not unlike those used for microelectronics fabrication. As a consequence, such processing is usually limited to high-value-added materials, such as for biologically compatible coatings. In plasma modification, a conventionally manufactured inexpensive polymer is treated with a plasma to change its surface properties. These processes are typically conducted at atmospheric pressure using corona discharge devices in a "web" arrangement. Unlike low-pressure plasma deposition, APP (atmospheric pressure plasma) processing of polymers is usually a low-value-added process. Polymers and plastics such as polypropylene and polyethylene are processed to improve their adhesion and wettability. In spite of the commercial use of APPs for treating polymers, there are few first order, fundamentals-based models describing the plasma-surface interactions that modify polymer surfaces. As a consequence, the development and optimization of APPs for polymer processing has been, for all practical purposes, an empirical undertakingBroader Impacts The economic and societal benefits of being able to adapt inexpensive and high-volume APP methods for modifying polymers to produce high-value films is staggering. For example, biocompatible artificial skin for treatment of burn patients could be produced for $1/m2 as opposed to $1,000's to $10,000's per m2 which is typical of newly FDA-approved products. The current knowledge base is inadequate to make these advances and improving that knowledge base will help determine the practicality of achieving these goals. The computational techniques and improvements in the knowledge base produced in this project are applicable to a variety of APP applications, including lighting, toxic gas remediation, sterilization of surfaces, bioremediation, and microdischarges..