In the last few years, biocide concentrations in fountain solutions have been steadily decreasing. This poses a potential risk of microbial contamination. The risk of so-called biofouling in the fountain solution circuits of presses is further increased by the reduction of antimicrobial isopropanol (IPA), which is typically added to fountain solutions due to its process-related advantages (e.g. more uniform film formation in the fountain unit).
These circumstances make it necessary to find new solutions to the problem of microbial contamination. For this reason, new substances, namely aggregation-induced emission (AIE) photosensitisers, are being used in fountain solutions as part of this research project. These should enable monitoring microbial contamination and offer the possibility of killing the micro-organisms.
Solution steps
The following steps are necessary to achieve the targeted results of the research project:
- Synthesising and characterising amphiphilic host monomers
- Development of a carrier matrix produced via 3D printing
- Optimisation of the release kinetics of the AIEs by computer simulation
- Laboratory tests to investigate the influence of fountain solution ingredients on the release behavior of the AIEs
- Checking the material compatibility of the AIEs with materials from printing presses
- Pilot tests in a printing press to verify the compatibility of the dosing system with printing processes
- Functionality and practical applicability tests in real-world operations as part of a field study
- Developing a concept for integrating the developed dosing systems into fountian solution circuits and maintenance instructions
Targeted results
The goal of this research project is to develop host-guest complexes that release AIE-active photosensitizers in a concentration-dependent manner, thereby ensuring their constant concentration in the fountain solution circuit. The host systems are ring-shaped structures within which the AIE-active photosensitizers are immobilized via reversible bonds (formation of host-guest complexes). Host-guest complexes are always in equilibrium with the free complex partners, whereby the rate at which guests are released from the host systems decreases as the binding strength of the host-guest complexes increases and as the concentration of free guests rises.
To achieve a needs-based release/dosage of the photosensitizers, the binding energies of the host-guest complexes formed by the photosensitizers with different host systems are calculated and simulations are performed to determine the release kinetics.
Through the on-demand dosing of photosensitizers, the method developed in the IGF preceding project 01IF22784N (AIE-active photosensitizers for monitoring and minimizing microbial contamination in the dampening solution circuit), it is possible to permanently minimize microbial contamination in the fountain solution circuit.