Laird, Mathilde

► Research

Thermo-reversible bond formation as a motif for alkoxysilane precursors: applications in drug delivery, self-healing and optoelectronics materials

Hybrid silica-based compounds have emerged as versatile precursors for the synthesis of organic-inorganic hybrid materials due to their higher chemical, mechanical and thermal stability compared to the more commonly used polymeric counterparts. Here, we will develop a new class of thermo-reversible poly-triethoxysilylated compounds based on linear and starburst molecules such as dendrimers and polyhedral oligomeric silsesquioxanes (POSS), and explore their use as a new synthetic platform for applications such as:

• Organic-inorganic hybrid nanoparticles for drug delivery, which can be degraded in a controlled manner via a remote trigger. Superparamagnetic cores will be integrated into the nanoparticles to generate heat and degrade the nanoparticles when a magnetic field is applied. The system will enable a variety of payloads to be released under controlled conditions and avoid the undesired accumulation of nanoparticles in organs.
• Self-healing “melting gels”. Conventional melting gels display a reversible softening with increasing temperature followed by irreversible consolidation of the material above a critical temperature. Herein, the softening will rely on the nature of the thermo-reversible bridging group and no consolidation temperature is anticipated. The reduced viscosity of the materials in the molten state is expected to improve the healing of cracks larger than those rehabilitated with conventional self-healing material. Using this strategy, self-healing ceramic- or glass-like materials with low healing temperatures (50 to 250 °C) will be developed.
• Functional porous materials templated by starburst precursors for optoelectronic applications. Starburst poly trialkoxysilanes will be integrated into a hybrid matrix, then removed by controlled cleavage. Their removal will lead to the creation of functionalised pores whose properties will depend on the pendant groups released by the removal of the dendrimer/POSS. After the grafting of optically-active dyes on the pendant groups, the quantum efficacy in confined environments with controlled dimensions will be studied.