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

加州大学戴维斯分校的 Gang-Yu Liu 获得了高分子、超分子和纳米化学 (MSN) 项目的资助，该项目旨在开发用于纳米精度三维 (3D) 打印的先进化学方法。 3D 打印机可以通过定制设计生产物体。 尖端的 3D 制造技术已达到高空间精度，低至 0.3 微米。 该项目旨在进一步将该技术在所有三个维度（人类头发的 1/800-1/100,000）小型化至真正的纳米级（100 nm）。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，该技术可引导化学反应，例如沿着探针的扫描轨迹逐层在表面上进行聚合，从而通过设计产生 3D 纳米结构。 这项工作将当前的 3D 功能扩展到纳米区域。 3D纳米打印生产的材料为光学和电子设备、催化、生物传感器和生物设备等各个领域提供了新的机遇，其中活性成分的局部环境决定了后续工艺和设备性能。 刘和她的团队计划继续通过加州大学戴维斯分校的项目（如 ACS 项目 SEED 项目和青年学者项目）与高中生合作，并通过戴维斯科学中心的 Nanoexplore 项目与公众合作。该项目利用了刘在 2D、高强度无孔径近场扫描光学显微镜 (NSOM) 和表面化学方面的分子分辨率纳米加工和成像技术。 使用 NSOM 激活光敏剂并局部产生自由基，将逐层利用光诱导硫醇-烯点击化学，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 NSOM 的空间精度，将 3D 制造扩展到纳米区域。 目标是在 3D 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) 精密机械运动和特征跟踪； (b) 使用扫描探针显微镜技术（包括 AFM 和无孔径 NSOM）进行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）具有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.