Exploring thiol-based chemistry for photopolymerizable inkjet inks and for advanced surface functionalization

Florian Mostegel

Research output: ThesisDoctoral Thesis

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Abstract

Concerns over deleterious effects of acrylate monomers limit their applicability in promising fields like food packaging materials. The first part of this work covers the investigation of an alternative system to the commonly used acrylate system in UV curable inkjet inks. One interesting alternative system is based on vinyl carbonates. Several monomers based on vinyl carbonate building blocks were synthesized and evaluated regarding their application in UV curable digital inks. Although the physical properties of these monomers were appropriate for inkjet printing, the curing speed turned out to be too slow for industrial use. The addition of multifunctional thiols improved the curing behavior (e.g. curing speed and conversion) similar to those for acrylates. However, commercially available multifunctional thiols proved to be of too high viscosity for the use in pigmented ink formulations. Consequently, a multifunctional thiol providing a lower viscosity and low odor was synthesized. Its application enabled the formulation of a basic inkjet ink offering an excellent printing behavior. The ink was further evaluated for its use on PET-substrates. Moreover, the shelf life of thiol-vinyl carbonate inks was investigated to evaluate their applicability in an industrial context. The second part of this work covers the investigation of thiol-reactions beyond the thiol-ene reaction used in the first part. In particular the photochemical oxidation of immobilized thiol groups and its applicability were investigated. For this matter thiol groups were immobilized on silicon substrates facilitating the monitoring of the reactions through analytical methods. The photo-oxidation of the thiol groups yielded sulfonic acid groups. Using photolithography or interference lithography patterned samples with oxidized and non-oxidized areas were obtained. Remaining thiol groups were evaluated for a photo-induced polymerization reaction under ambient conditions for a facilitated polymer brush patterning. The generated sulfonic acid groups were evaluated for further derivatization with amino-functionalized molecules after activation with triphenylphosphine ditriflate. The combination of both reactions enabled the site-specific immobilization of green fluorescent protein in previously photo-oxidized regions, while the thiol groups in the non-photo-oxidized regions were exploited for the growth of non-specific adsorption inhibiting polymer brushes. The investigated thiol chemistry beyond the thiol-ene reaction, starting with the photo-oxidation and the subsequent derivatization steps, expand the known strategies for the fabrication of complex protein nanopatterns.
Translated title of the contributionDer Einsatz von Thiol-Chemie in photopolymerisierenden Druckertinten und zur Oberflächenfunktionalisierung
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Hofer, Ferdinand, Assessor B (external), External person
  • Griesser, Thomas, Assessor A (internal)
Publication statusPublished - 2015

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