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K. Cicha, Z. Li, K. Stadlmann, J. Torgersen, R. Markut-Kohl, R. Liska, J. Stampfl:
"Fabrication and evaluation of 3D-micro-structures produced using two-photon-induced photopolymerization (TPIP or 2PP) by means of optical assessment and FTIR-spectroscopy";
Talk: 16. Tagung Festkörperanalytik, Wien; 07-04-2011 - 07-06-2011.

Two-Photon Polymerization (2PP) has recently gained a lot of interest as additive manufacturing technology capable of fabricating complex 3D submicron structures. Parts produced with this technology can be used in various future applications e.g. mechanical, electronic and optical micro devices. This paper presents achievements in the fabrication of 3D-micrometer-structures as well as two methods and procedures for evaluating photopolymers in terms of their usability for 2PP.

For material research a reliable evaluation system is indispensable to compare different materials. Due to the small sample size and long fabrication-times (typical feedrates are between 100μm/s and 1mm/s) traditional material testing methods (e.g. tensile test, notch-bar impact test, etc.) cannot be used for 2PP-structures. Therefore more applicable methods had to be developed to provide a solid base for investigations on the 2PP process.
In this paper two different methods for evaluating 2PP-structures are described. One method works by optical assessment giving immediate response about the applicability of the material for 2PP. For the second method the double-bond conversion of fabricated 2PP-structures was measured giving quantifiable results about the efficiency of the photoinitiator. The method is based on locally measuring the double bond conversion of the photopolymer using a microscope in combination with infrared spectroscopy. The obtained double bond conversion is a measure for the efficiency of the photopolymer system (initiator in combination with monomer), and thus allows to compare different photopolymers in a quantitative way.
Beside this evaluation of 2PP-structures fabrication of complex 3D-structures was done to determine the limits of the 2PP technology for miscellaneous components.

Two-Photon Polymerization, Additive Manufacturing Technologies, 3D-Writing

http://publik.tuwien.ac.at/files/PubDat_201803.pdf

Project Head Jürgen Stampfl:
ISOTEC III - Integrated Organic Sensor and Optoelectronic Technologies (Phase 3)