Super-Resolution Photochromic Switching for Bicontinuous Nanostructures

在这个由化学系大分子、超分子和纳米化学项目资助的项目中，伦斯勒理工学院的Chaitanya Ullal教授和Edmund F. Palermo教授正在利用可见光精确地指导大型纳米结构的合成。这种合成方法结合了几种不同的基于光的技术，让人想起经典摄影，除了它不需要使用光掩膜的投影图像。这种方法可以制造非常小的图案，小到几十纳米大小。它还提供了对物体形状和大小的精确控制。此外，图案可以经济有效地在整个表面上印刷。与该奖项相关的研究有可能实现超分辨率3D打印，而无需使用昂贵的先进设备。这些新技术可以推动生物医学设备的设计和其他先进制造应用。该研究小组正在继续致力于教育和社区外展，特别强调通过创新的基于家庭的学习活动和设计项目促进妇女和代表性不足的少数民族参与科学。更广泛的教育影响包括动手学习活动的创建，教育视频的开发以及K-12学生的指导，所有这些都激励和促进了代表性不足的学生参与STEM领域。本研究的核心目标是利用功能大分子化学和先进光学，特别是超分辨率光学和干涉光刻技术的结合，创造3D双连续纳米结构材料。在第一个目标中，开发了对实现超分辨率3D干涉光刻所需的潜在化学动力学的更深入的基本理解。合成了具有系统变化结构特征的螺iopyran衍生物库，以精确调整光开关和点击反应的动力学，从而产生交联聚合物凝胶或热固性聚合物。第二个目标侧重于开发一个自洽计算模型，该模型捕获三维变化的光和化学浓度场作为时间函数的耦合相互作用。微分方程的自洽解使得在化学浓度演化的每个时间步上都可以进行电磁模拟；这与传统的有限元（FEA）或时域有限差分（FDTD）技术（令人望而却步的长计算时间）不同。最后一个目标集中在双连续超分辨率纳米结构中，其中三维超分辨率干涉光刻的配置由均匀激发曝光和由多束相干光干涉获得的耗尽模式组成。利用非掩模光对纳米结构材料的形成进行控制，并在大范围内进行精确控制，有可能推动光子晶体、微桁架和生物医学设备的发展。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professors Chaitanya Ullal and Edmund F. Palermo at Rensselaer Polytechnic Institute are using visible light to precisely direct the synthesis of large nanostructures. The synthesis method utilizes a combination of several different light-based techniques and is reminiscent of classical photography, with the exception that it does not require a projected image using a photomask. The approach can create extremely small patterns, down to a few tens of nanometers in size. Precise control of the shape and size of the objects it creates is also provided. Additionally, patterns can be printed over an entire surface cost-effectively. Research associated with this award has the potential to enable super-resolution printing in 3D without the need to utilize expensive state-of-the art equipment. The new techniques could advance the design of biomedical devices and other advanced manufacturing applictions. The research team is continuing their commitment to education and community outreach, with a particular emphasis on promoting women and under-represented minorities in science through innovative family-based learning activities and design projects. The educational broader impacts include the creation of hands-on learning activities, the development of educational videos, and the mentorship of K-12 students, all of which inspire and promote participation of under-represented students in STEM fields. The central goal of this research is to create 3D bicontinuous nanostructured materials using a combination of functional macromolecular chemistries and advanced optics, especially super-resolution optics and interference lithography. In the first objective, a deeper fundamental understanding of the underlying chemical kinetics needed to enable super-resolution 3D interference lithography is developed. A library of spirothiopyran derivatives with systematically varied structural features is synthesized in order to precisely tune the kinetics of photo-switching and click reactions leading to a cross-linked polymer gel or thermoset. The second objective focuses on the development of a self-consistent computational model that captures the coupled interaction of the three dimensionally varying light and chemical concentration fields as a function of time. Self-consistent solution of differential equations results in an electromagnetic simulation at each time step of the chemical concentration evolution; This is a departure from conventional finite-element (FEA) or finite-difference time-domain (FDTD) techniques (prohibitively long computation times). The last objective concentrates on bicontinuous super-resolution nanostructures in which the configuration of 3D super-resolution interference lithography consists of a uniform excitation exposure and a depletion pattern that is obtained by the interference of multiple beams of coherent light. Control over the formation of nanostructured materials using unmasked light, with precision over large areas, has a potential to advance the development of photonic crystals, microtrusses and biomedical devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.