The polymerization of silyl ether containing thiols and alkenes results in tunable, degradable thermosets with potential in implantable electronics.

Multifunctional thiols were synthesized by the selective reaction of chlorosilanes with mercaptoalcohols. Reaction of the mercaptoalcohols through the thiol group was not observed. Utilizing this method, thiols of varying structural diversity were prepared.

Two new trifunctional alkene monomers based on the highly modular perfluoropyridine scaffold were synthesized with an aliphatic and an aromatic moiety, 4penten-1-ol and eugenol, respectively. The monomers were the basis for thiol-ene thermoset materials, formulated against a difunctional or trifunctional thiol. Systems based on these novel monomers have a wide range of thermal properties, with glass transition temperatures spanning from -42 °C to 21 °C. Mixed systems obey the Fox equation, and T g s of the mixtures can be tuned to specific values in that range. Thermal degradation temperatures follow a similar trend, with decomposition temperatures ranging from 274 °C to 348 °C in nitrogen with varying compositions having tailorability therein. This new class of semifluorinated thermoset materials with tunable thermal properties has several potential applications within the aerospace industry, such as sealants and coatings, where stability and survivability at high temperatures in harsh environmental conditions are imperative.

Hybrid systems in which poly(ether sulfone) (PESU) chains are grafted to semifluorinated polyhedral oligomeric silsesquioxane (POSS) cores are expected to integrate the advantages of both fluoropolymers and POSS into the polymer system to yield excellent surface properties. For that purpose, we synthesized a novel octa-functional perfluorocyclopentenyl-POSS (PFCP-POSS), which was used as a "core" grafting point. Commercial PESU was successfully grafted to PFCP-POSS via the nucleophilic addition-elimination reaction between the phenolic chain ends and reactive PFCP moieties to yield a hybrid branched polymer possessing a semifluorinated POSS core. X-ray photoelectron spectroscopy, neutron reflectivity, and atomic force microscopy indicated that the preparation of nanostructured polymer surfaces occurs by migration of the low surface energy components (PFCP-POSS molecules), while POSS aggregation is suppressed by covalent attachment to the long PESU chains. The resulting PFCP-POSS modified PESU films were highly transparent and yielded hydrophobic surfaces with low surface energy and high modulus for potential applications in high performance coatings and composites.

High-temperature linear fluoropyridyl silicone-based oils and network elastomers were prepared via hydrosilylation with multifunctional perfluoropyridine (PFP)-based monomers possessing terminally reactive alkenes. Monomers with varying degrees of functionalization were prepared in a scalable manner and in high purity via the facile, regio-selective, nucleophilic aromatic substitution (SNAr) of PFP in good isolated yields. These multi-reactive monomers were polymerized via Pt-catalyzed hydrosilylation with hydride-terminated polydimethylsiloxanes (H-PDMSs) possessing varying degrees of polymerization and cross-linked with the highly functionalized octadimethylhydrosilyl cubic siloxane. These resulting polymers of varying architecture possessed exceptional thermal stability with no onset of degradation up to 430 °C and char yields as high as 62%, under inert pyrolysis conditions when modified with cubic siloxane. Furthermore, by nature of the aliphatic or aromatic content, programmable glass transition temperatures were achieved from these elastomeric materials. Finally, the linear 3,5,6-fluoropyridine PDMS systems demonstrated the ability to undergo regio-controlled post-functionalization via SNAr with 4-bromophenol, allowing access to silicone oils with potentially tailorable properties for desired applications.