SBIR Phase I: Thermally Stable, Flexible Substrates for Flat Panel Displays

该小型企业创新研究第一阶段项目将确定生产柔性、高度透明的聚酰亚胺薄膜的可行性，该薄膜具有热稳定性、高玻璃化转变、近零双折射和低热膨胀系数（CTE）。该材料被设计用作柔性平板显示器基板。没有可用的材料显示所有这些属性。关键的技术问题将是设计一种分子结构，平衡低膜双折射，这通常需要一个灵活的聚合物，和CTE，这通常需要一个刚性的聚合物。这一明显的矛盾将通过制备包含正双折射单元和负双折射单元的刚性共聚物来解决。这些单位的比率将被改变以在材料的膜中获得零双折射。由于刚性共聚物的溶液浇铸将导致各向同性的面内链取向，因此这些共聚物膜应显示低CTE以及低双折射。 将开发聚合物结构和膜性质之间的结构性质关系。这将进一步科学地理解分子结构和材料特性之间的相互作用。该项目的更广泛/商业影响包括增强对这些新材料的科学和技术理解，这将使下一代显示技术成为可能，包括柔性液晶（LC）显示器。目前，仅LC显示器市场就是一个每年千亿美元的产业。柔性显示器将占据该市场的很大一部分，并为便携式柔性显示器开辟新市场。这些包括可以集成到衣服上的舒适显示器，柔性电子纸和电子书显示器，智能卡显示器以及许多其他新应用。这些新设备将通过降低成本、增加流媒体信息的可访问性和便携性，极大地影响日常生活。目前的柔性基板是不透明的，因此限于反射模式显示器，或者具有低处理温度，这显著限制了它们的性能以及显示器应用的数量和范围。如果成功，该项目下开发的基板有望首次实现柔性液晶显示器的高温加工，从而开启更高性能的新型显示设备的潜力。

This Small Business Innovation Research Phase I project will establish the feasibility of producing a flexible, highly transparent polyimide film that is thermally stable, has a high glass transition, displays near zero birefringence and a low coefficient of thermal expansion (CTE). This material is designed for use as a flexible flat panel display substrate. No available material displays all of these properties. The key technical problem will be the design of a molecular architecture that balances low film birefringence, which generally requires a flexible polymer, and CTE, which generally requires a rigid polymer. This apparent paradox will be addressed through the preparation of a rigid copolymer that contains both positive and negative birefringent units. The ratio of these units will be varied to obtain zero birefringence in a film of the material. Since solution casting of the rigid copolymer will result in isotropic, in-plane chain orientation, these copolymer films should display low CTEs as well as low birefringences. Structure property relationships between the polymer architecture and the film properties will be developed. This will further the scientific understanding of the interplay between molecular architecture and material properties. The broader/commercial impact of this project includes enhanced scientific and technological understanding of these new materials which will enable the next generation of display technologies which includes flexible liquid crystal (LC) displays. Currently the LC display market alone is a hundred-billion dollar a year industry. Flexible displays would consume a large fraction of that market as well as open-up new markets for portable flexible displays. These include conformable displays that can be integrated onto clothing, flexible e-paper and e-book displays, displays for smartcards, and a host of other new applications. These new devices would dramatically impact daily life, by decreasing the cost and increasing accessibility and portability of streaming information. Current flexible substrates are either non-transparent, and so are limited to reflection mode displays, or have low processing temperatures which dramatically restricts their performance as well as number and range of display applications. If successful, the substrates to be developed under this project is expected to enable, for the first time, high temperature processing of flexible LC displays, opening the potential of new display devices of higher performance.