Nanoprägen in Polymerfolien als Fertigungsverfahren für fluidische Mikro Nano Systeme Nanoembossing in Polymer Foils as a Fabrication Technique for fluidic Micro Nano Systems

Um die Funktionalität der Mikrosystemtechnik durch die Integration von Submikrometer und Nanometerstrukturen in sogenannte Mikro Nano Systeme erweitern zu können, müssen industriekompatible Produktionstechnologien entwickelt werden, die eine Strukturierung im Mikro und Nanometerbereich für ein breites Nutzerspektrum ermöglichen und für eine Fertigung von mikro und nanostrukturierten Komponenten auch im industriellen Einsatz in Frage kommen. Die Intention der vorliegenden Arbeit ist es, für diese technologische Aufgabenstellung einen möglichen Lösungsansatz durch Untersuchungen zum Nanoprägen als ein für die Nanostrukturierung von Kunststoffen adaptiertes Heissprägeverfahren weiterzuentwickeln und den enormen Nutzen des Verfahrens für die Fertigung fluidischer Mikro Nano Systeme durch Applikationsbeispiele aus dem Bereich der Life Sciences zu veranschauliche

Replication of high aspect ratio pillar array structures in biocompatible polymers for tissue engineering applications

We developed a simple two-step replication method to transfer arrays of high aspect ratio nanopillars into films of poly(L-D,L-lactic acid) (PLLA). Such structures are promising model surfaces for tissue engineering applications. From arrays of 1 mu m high and 200 nm wide pillars produced with e-beam lithography and reactive ion etching negative replicas were first formed by polydimethylsiloxane (PDMS) casting. The final replicates were produced by solvent casting from 1% to 4% solutions of PLLA in chlorinated solvents on the PDMS templates. The silicon masters provide excellent stability and reusability, whereas the flexibility and low surface energy of the PDMS are necessary for the separation of the casts made with PLLA, a brittle material which is difficult to handle. AFM and SEM characterizations confirmed a high fidelity reproduction of the structures with aspect ratios of 1:5. In vitro tests using mouse neural stem cells seeded on nanopillars showed that the cells sense the nano-sized topography and respond accordingly by orienting themselves

Thermal nanoimprint resist for the fabrication of high-aspect-ratio patterns

We report a newly developed thermal nanoimprint (T-NIL) resist specifically engineered for the implementation in a bilayer system rendering the fabrication of high-aspect-ratio patterns. The synthesis of the T-NIL resist was accomplished by applying a free radical copolymerization of adequate comonomers. Due to the modular architecture of the terpolymer, the rather different material properties are directly adjusted by varying the amount of the comonomers and also by tuning the polymerization conditions like temperature and the amount of initiator. Following this synthetic strategy, the Si content for a sufficient oxygen plasma resistance as well as an excellent flowability behavior for a significant reduction of the overall processing cycle time could be easily achieved. Moreover, the already good mould release properties of the pure T-NIL resist can be further improved by the addition of a small amount of a fluorinated additive leading to a very low defect rate of the imprinted structures