Rational design of polymer networks
Soft materials are highly versatile and tuneable materials, thus interesting for a large area of applications. Engineering the network topology and molecular interactions between constitutive components enable precise tuning of the emergent macroscale properties. However, to target specific applications, we need to understand how the (macro)molecular structure of the material controls the resulting macroscopic properties. A central focus of our laboratory is to synthesize and characterize a range of polymer networks, probing different chemical strategies to obtain materials with a variety of properties.
Materials characterization
To obtain insights into material structure and its macroscopic properties, we perform a broad range of characterization techniques. We use spectroscopic techniques (NMR, FTIR, UV-Vis) to analyse molecular structures and probe molecular interactions with isothermal titration calorimetry (ITC). To characterize macroscopic properties of our materials, we perform extensive rheological and photorheological analyses and tensile testings. Combining these techniques allows us to relate the observed macroscopic material properties to the molecular structure of the network, enabling us to tailor properties of our materials to targeted applications.
Polymers with high durability and on-demand degradability
Plastic materials often show a mismatch between degradability and durability. While on-demand degradability is achievable through the incorporation of labile bonds, these bonds are disadvantageous when incorporated into high-performance plastics leading to their premature aging and loss of the material’s properties over time. Maintaining the properties of high-performance plastics throughout their lifetime is as important as degrading them at the end of their life. To potentially bridge degradability and durability, in this project, we design a new class of polymeric materials based on thioimidates. The thioimidates provide durability through a self-healing and self-reinforcement mechanism, while on-demand degradation is achieved in acidic environments. By changing the chemical structure of the monomers, we can tune the properties of the final polymers.
People involved: Carolina Söll, Dr. Stefan Mommer
Photoreversible materials for digitally printed temporary films
Temporary masks are used for protection during mechanical and chemical processing and have a broad range of applications, especially in fields such as the watch industry, where complex surface finishing is required. To enable digital printing of these masks, we are developing a printable ink based on a reversible photopolymer. The ink is cured (hardened) with light and removed tracelessly on demand via irradiation with a second wavelength of light. Our approaches are based on different chemistries that build upon the photocleavage capabilities of ortho-nitrobenzyl (oNB) moieties. We synthesize new photocleavable molecules and adjust formulations for both printability and compatibility with industrial masking processes on various substrate materials.
People involved: Morris Wolf
Integration of supramolecular host–guest complexes in polymer networks for controlled drug delivery
Polymer networks have been increasingly explored as drug delivery systems. One strategy to ensure controlled release of drugs or therapeutics is by introducing drug–polymer interactions. Those can be of covalent or physical nature with varying binding affinities, typically slowing down the cargo diffusion and thus prolonging its release. We are developing polymer networks with threaded host macrocycles that can be loaded with a small drug/cargo molecules. Due to the binding affinity between the cargo molecule and the host, the cargo diffusion will be slowed down. Additionally, we are exploring the correlation between the binding strength of cargo molecules and the kinetics profile of the release.
People involved: Nika Petelinsek, Dr. Stefan Mommer