CAREER: Monolayer Templated Growth of Organic Crystals

职业：有机晶体的单层模板生长

• 批准号: 9703102
• 负责人: Guangzhao Mao
• 金额: $ 22.8万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-15 至 2002-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9703102&HistoricalAwards=false
• 关键词: CAREER; Monolayer; Templated; Growth; Organic

ABSTRACT CTS-9703102 This Career project investigates alternative interfacial chemical approach to crystal growth using monolayer templates. Morphological control is extremely important in the synthesis and processing of organic crystals, especially those with anisotropic electronic, optical, conductive, and electromagnetic properties. Molecular-level model compounds are largely lacking in current approaches to crystal growth. One class of polymethine dyes is well suited for such models, due to its (1) dichroic optical properties, (2) morphological sensitivity to interfacial forces, (3) J-aggregates and energy transfer within, and (4) functions in color photography and recording, as well as in ultra-fast lasers and strongly enhanced nonlinear optics. The structure and morphology of organic crystals are determined by a delicate force balance of van der Waals, Coulombic, hydrogen bonding, and electron orbital forces. Preliminary results have shown: (1) the polymethine crystal displays strong optical anisotropy; (2) its structure is sensitive to minor steric changes; and (3) its morphology is sensitive to substrate hydrophobicity. It is possible to control crystal morphology by changing the nuclei attachment energy using monolayer templates with varying affinities to different crystal faces. The goal of the proposed research is to grow organic crystals with uniform optical properties by controlling their microstructure and orientation at the substrate surface. The principle of monolayer templated crystal growth is that the interfacial energy and specific binding sites enhance the attachment of similar crystal faces and inhibit the others. In the following figure, crystal orientation can be achieved by using surface groups with different affinities to the faces of the crystal, and the crystal size can be limited by lattice mismatch and micro-domains in mixed monolayers. Solid-bound self-assembled and liquid-bound Langmuir monolayers are used as crystal growth templates. Self-assembly of silanes modifies the silica substrate by incorporating terminal groups of different critical surface tensions and degrees of electrophilicity. The charge resonance and electron donor/receptor interactions have been suggested to be the origin of the spectral red-shift in J-aggregates. Monolayers formed at the air/water interface of mixed custom-made chromophore-containing amphiphiles and regular amphiphiles are used to study comparatively the specific interaction between conjugated dye functional groups. A combined approach of spectroscopic and microscopic methods is used to characterize the monolayer/crystal complex at the molecular level and in situ. Real-time investigation of the microstructure and interfacial bonding development of dye crystals on monolayer templates will be carried out by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). In addition, the monolayer structure and surface energy are determined by a combination of contact angle, FTIR, AFM imaging and pull-off force measurements. The crystal structure and optical properties are determined by AFM, polarized optical microscopy, and UV-vis spectroscopy with the aid of computer-generated three dimensional models. Experimental results from the proposed research are expected to contribute to the field in the following ways: (1) functionalizing organic monolayers for crystal growth; (2) obtaining uniform optical properties by template-induced orientation of crystal faces; (3) understanding optoelectronic properties of dye crystals and J-aggregates based on microstructural study; (4) observing and understanding early stages of crystallization; and (5) assisting the development of photographic sensitizing dyes with versatile and new properties. In conclusion, this program proposes an alternative chemical approach to rational design and assembly of organic thin films and crystals based on molecular level interactions and characterization. It pursues the functionalization of organic thin films as templates for crystal growth of an important class of materials. It has the potential of understanding the molecular principles behind the self-organization of ordered materials. In the education plan, the PI plans to interface her research in interfacial materials engineering with the undergraduate education through the integrated Advanced and Materials Engineering Laboratory, and to bridge the gap between academia and industry by incorporating the latest development in automotive related research into the Graduate Certificate Program in Polymer Engineering.

摘要CTS-9703102该职业项目研究了使用单层模板研究替代的界面化学方法。形态控制在有机晶体的合成和加工中极为重要，尤其是那些具有各向异性电子，光学，导电和电磁特性的晶体。 分子级模型化合物在当前的晶体生长方法中基本上缺乏。 一类多肽染料非常适合此类模型，由于其（1）二分色光学特性，（2）对界面力的形态学敏感性，（3）J-Aggregaties和（4）在彩色摄影和记录中的功能以及（4）在Ultra-Mota-of to摄影和记录中的功能，以及在Ultra-Mota-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of-of to的激光器和强烈强烈的非细胞和强度良好。 有机晶体的结构和形态由范德华，库仑，氢键和电子轨道力的微妙力量平衡确定。 初步结果表明：（1）多叶氨酸晶体显示出强的光学各向异性； （2）它的结构对小空间变化敏感； （3）其形态对底物疏水性敏感。 可以通过使用单层模板改变对不同晶体面的单层模板来改变核形态，从而控制晶体形态。 拟议的研究的目的是通过控制其微结构和方向在底物表面来生长具有均匀光学特性的有机晶体。 单层模板晶体生长的原理是，界面能量和特定的结合位点增强了相似晶体面的附着，并抑制了其他晶体。 在下图中，可以通过使用与晶体面部不同亲和力的表面基团来实现晶体取向，并且在混合单层中的晶格不匹配和微型域可以限制晶体大小。实体结合的自组装和液体结合的Langmuir单层用作晶体生长模板。 硅烷的自组装通过结合不同临界表面张力和亲电度程度的末端组来修饰二氧化硅底物。 电荷共振和电子供体/受体相互作用已被认为是J种群中光谱红移的起源。 在混合定制发色团的两亲物和常规两亲物的空气/水界面形成的单层用于研究共轭染料官能团之间的特定相互作用。 光谱和微观方法的组合方法用于表征分子水平和原位的单层/晶体复合物。 对单层模板上染料晶体的显微结构和界面键合的实时研究将通过原子力显微镜（AFM）和傅立叶变换红外光谱（FTIR）进行。 另外，单层结构和表面能由接触角，FTIR，AFM成像和拉动力测量的组合确定。 晶体结构和光学性质由AFM，极化光学显微镜和UV-VIS光谱确定，借助计算机生成的三维模型。 拟议研究的实验结果预计将以以下方式为该领域做出贡献：（1）使有机单层功能化晶体生长； （2）通过模板引起的晶体面取向获得均匀的光学性能； （3）根据微观结构研究，了解染料晶体和J聚集物的光电特性； （4）观察和理解结晶的早期阶段； （5）协助使用多功能和新特性的染料染料的开发。 总之，该程序提出了一种基于分子水平相互作用和表征的有机薄膜和晶体的理性设计和组装的替代化学方法。 它追求有机薄膜作为重要材料晶体生长的模板的功能化。 它具有理解有序材料自组织背后的分子原理。 在《教育计划》中，PI计划通过综合的高级和材料工程实验室将其在界面材料工程中的研究与本科教育相连，并通过将自动性相关研究的最新发展纳入聚合物工程研究生证书计划中，以弥合学术界和行业之间的差距。