Microfabrication of 3D-hydrogels via two-photon polymerization of poly(2-ethyl-2-oxazoline) diacrylates

Wloka, Thomas; Czich, Steffen; Kleinsteuber, Maximilian; Moek, Elisabeth; Weber, Christine; Gottschaldt, Michael; Liefeith, Klaus; Schubert, Ulrich S.

Abstract:

Bis(acrylate) functionalized poly(2-ethyl-2-oxazoline)s (PEtOx-DA) served as macromonomers as well as crosslinkers for the structured two-photon polymerization (2PP) using a novel water soluble photoinitiator (PI). The telechelics were obtained via end capping of the trans-1,4-dibromo-but-2-ene (DBB) initiated cationic ring-opening polymerization (CROP) of 2-ethyl-2-oxazoline. Analysis of the PEtOx-DA by means of mass spectrometry, nuclear magnetic resonance spectroscopy and size exclusion chromatography revealed that the CROP in refluxing acetonitrile was successfully scaled-up from 10 g to 200 g for degrees of polymerization of 10 and 18, respectively. The PI based on a cyclopentanone dibenzylidene based donor-acceptor-donor π system coupled to an acrylate functionalized triaryl amine proved suitable to produce structured hydrogels. Fabricated voxel arrays with different shot times and laser intensities revealed voxel widths below 20 µm showing a similar structuring capability with high resolution of PEtOx-DA as well as for poly(ethylene glycol) diacrylate (PEG-DA) via 2PP. The properties of obtained structures were characterized by a series of line arrays as well as designed Spider-Web-patterns. PEtOx-DA revealed enhanced suitability in comparison to the used PEG-DA.

Year:

2020

Type of Publication:

Article

Journal:

European Polymer Journal

Volume:

122

Number:

109295