Fabrication and Characterization of 2D and 3D Nanostructures via Lithography

: Exploring Paramagnetic Effects on Polymerization

Abstract

This thesis investigates the development of sustainable, vitamin-based photoinitiator systems supported by PEG for advanced 3D lithography. The motivation behind this work lies in the search for bio-inspired and environmentally friendly alternatives to conventional photoinitiators used in micro- and nano structuring. The study begins with a theoretical overview of polymerization mechanisms, photoinitiator chemistry, and the fundamental principles of single-photon (SPL) and multiphoton lithography (MPL). Building on this foundation, a series of vitamins were selected and characterized by UV-Vis spectroscopy to evaluate their optical properties and excitation suitability at 515 nm and 1030 nm. Experimentally, PEG-based matrices were prepared with different vitamins and, in some cases, supplemented with co-initiators such as MnCl₂. A standardized lithographic writing protocol—featuring defined power and speed gradients—was employed to ensure reproducible comparison across all systems. Microscopic analysis of the written structures provided insight into polymerization thresholds, working ranges, and line stability. The results revealed notable variations in initiation efficiency among the tested systems. While ascorbic acid showed limited activity, nicotinamide and folic acid (B9) demonstrated high sensitivity and wide operational windows. Vitamin B12 required higher powers for stable polymerization but exhibited substantial improvement when combined with MnCl₂. PEG alone displayed only weak autoinitiation under the given conditions. Overall, this work emphasizes the strong interplay between initiator chemistry, solvent environment, and excitation wavelength in determining lithographic performance. The findings identify folic acid and nicotinamide as particularly promising candidates for sustainable 3D lithography and highlight the potential of co-initiator strategies, such as B12 + MnCl₂, to enhance weaker systems. In doing so, the thesis contributes to the advancement of greener, bio-inspired photoinitiator systems for future applications in micro- and nanofabrication.

Date of Award	2025
Original language	English
Supervisor	Jaroslaw Jacak (Supervisor)