Three Dimensional Nanolithography via Combined Scanning Near-Field Optical Microscopy and Photopolymerization

加州大学戴维斯分校的刘刚宇获得了大分子、超分子和纳米化学(MSN)计划的支持，该计划旨在为纳米精度的三维(3D)打印开发先进的化学方法。3D打印机可以通过定制设计来生产物品。尖端的3D制造技术已经达到了很高的空间精度，精度可以达到0.3微米。该项目旨在将这项技术进一步微型化到真正的纳米尺度，100纳米，在所有三个维度(人类头发的1/800-1/100,000)。这将通过使用近场扫描光学显微镜技术的非常小的光源来实现，该技术可以引导化学反应，例如在表面上逐层聚合，跟随探针的扫描轨迹，并因此通过设计产生3D纳米结构。这项工作将目前的3D能力扩展到纳米区域。3D纳米打印生产的材料在包括光学和电子器件、催化、生物传感器和生物设备在内的各个领域提供了新的机会，其中活性成分的本地环境决定了后续的工艺和设备性能。刘和她的团队计划继续通过加州大学戴维斯分校的种子计划和青年学者计划等项目与高中生合作，并通过戴维斯科学中心的纳米探索计划与普通公众合作。该项目利用了刘的分子分辨率纳米加工和2D成像技术、高强度无孔近场扫描光学显微镜(NSOM)和表面化学。使用NSOM来激活光敏剂并在局部产生自由基，光诱导的硫醇-烯点击化学将被逐层利用，按照设计的几何形状产生设计的3D结构。与目前使用的支持微光刻的3D打印机不同，这项研究利用了NSOM的空间精度，并将3D制造扩展到纳米区域。其目标是在三维纳米光刻中实现最高的空间精度和分辨率。学生培训包括：(A)精确的机械运动和特征跟踪；(B)使用包括原子力显微镜和无孔NSOM在内的扫描探针显微镜技术的高分辨率成像和结构表征；(C)计算机编程和3D打印方面的高级技能；(D)纳米环境中的表面化学，包括吸收、图案转移和解吸；以及(E)高空间分辨率的光聚合化学。

Gang-Yu Liu at the University of California-Davis is supported in an award from the Macromolecular, Supramolecular and Nanochemistry (MSN) Program that aims at developing advanced chemistry methodologies for three-dimensional (3D) printing with nanometer precision. 3D printers enable production of objects by custom-design. Cutting-edge 3D fabrication technology has reached high spatial accuracy, down to 0.3 micrometers. This project aims at further miniaturizing the technology down to genuine nanometer scale, 100 nm, in all three dimensions (1/800-1/100,000 of human hair). This will be achieved by a very small light source using near-field scanning optical microscopy technology that directs a chemical reaction, such as polymerization on a surface, layer-by-layer, following the scanning trajectory of the probe, and as such producing 3D nanostructures by design. The work extends current 3D capability into the nanometer region. The materials produced by 3D nanoprinting provide new opportunities in various fields including optical and electronic devices, catalysis, and biosensor and biodevices where the local environment of active ingredients dictate the subsequent processes and device performance. Liu and her team plan to continue their outreach effort in working with high school students via UC Davis programs such as the ACS Project SEED program and Young Scholars Program, and with the general public via the Davis Science Center, Nanoexplore program.The project takes advantage of the Liu's molecular resolution nanofabrication and imaging technology in 2D, high intensity apertureless near field scanning optical microscopy (NSOM), and surface chemistry. Using NSOM to activate a photosensitizer and produce radicals locally, photoinduced thiol-ene click chemistry will be utilized layer-by-layer, following the designed geometry to yield the designed 3D structures. Unlike currently used 3D printers that enable microlithography, this research takes advantage of NSOM's spatial precision and extends 3D fabrication to the nanometer region. The goal is to achieve the highest spatial precision and resolution in 3D nanolithography. Student training includes: (a) precision mechanic movement and feature tracking; (b) high resolution imaging and structure characterization using scanning probe microscopy technology including AFM and apertureless NSOM, (c) advanced skills in computer programing and 3D printing; (d) surface chemistry at nanoenvironment including absorption, pattern transfer, and desorption, and (e) photopolymerization chemistry with high spatial resolution.