Thiol-Ene polymerization is also known since the 50’s of the last century and has gained tremendously increasing interest during the last decade, thanks to the rediscovery by Hoyle [1] and recent efforts by Bowman [2]. Advantages such as low oxygen inhibition and shrinkage, uniform networks with significantly improved mechanical properties are accompanied by up to now unsolved disadvantages such as unpleasant odour and poor storage stability.

Very recently we were able to introduce a new concept in thiol-ene stabilization which gives excellent storage stability with nearly no increase in viscosity with several months up to one year [3].

Vinylesters and vinylcarbonates [4] are a promising class of new, low toxic monomers not only for biomedical applications [5] but also for classical coatings. The only limitation of moderate reactivity between those of methacrylates and acrylates has been circumvented by thiol-ene polymerization [6].

With newly designed two photon initiators we were also able to show the 3D printing of hydrogels based on vinylester-modified gelatin with free thiol-groups of bovine serum albumin, for potential tissue engineering application.

[1]  Hoyle, C. E.; Hensel, R. D.; Grubb, M. B. J Polym Sci, Polym Chem (1984), 22(8), 1865-73

[2] Cramer, Neil B.; Bowman, Christopher N. J Polym Sci, Polym Chem (2001), 39(19), 3311-3319.

[3] (a) Cherkaoui Z.; Esfandiari P.; Frantz R.; Lagref J.-J.; Liska R. WO2012126695  (A1)

      (b) P. Esfandiari, S. Ligon, J. Lagref, R. Frantz, Z. Cherkaoui, R. Liska:
"Efficient Stabilization of Thiol-ene Formulations in Radical Photopolymerization";
Journal of Polymer Science Part A: Polymer Chemistry, 51 (2013), S. 4261 - 4266.

[4] B. Husar, R. Liska:
"Vinyl carbonates, vinyl carbamates, and related monomers: synthesis, polymerization, and application";
Chemical Society Reviews, 41 (2012), S. 2395 - 2405.

[5] C. Heller, M. Schwentenwein, G. Russmüller, T. Koch, D. Moser, C. Schopper, F. Varga, J. Stampfl, R. Liska:
"Vinylcarbonates and Vinylcarbamates: Biocompatible Monomers for Radical Photopolymerization";
Journal of Polymer Science Part A: Polymer Chemistry, 49 (2011), 3; S. 650 - 661.

[6] A. Mautner, X.H. Qin, B. Kapeller, G. Russmüller, T. Koch, J. Stampfl, R. Liska:
"Efficient Curing of Vinyl Carbonates by Thiol-Ene Polymerization";
Macromolecular Rapid Communications, 33 (2012), 23; S. 2046 - 2052.