Independent Control of Barrier Properties in Thiol-Yne Click Polymers

Abstract

Several preclinical, implantable technologies including transient health monitors, degradable orthopedic implants, and long-term implants are underserved by commercially-available barrier polymers with respect to degradation profile and biofluid barrier performance. In this work, we present thiol-Yne click chemistry as a synthetic platform for the preparation of new barrier materials fueled by previous observations that polymer crystallinity can be decoupled from degradation profile via the two separate routes of control over polymer properties: polymer composition and alkene stereochemistry. We independently varied the composition and alkene stereochemistry of several thiol-Yne materials to probe their effect separately on polymer crystallinity and water vapor barrier performance. Dynamic vapor sorption (DVS) analysis, a gravimetric method, and water vapor transmission rate (WVTR) measurements, sensitive to perpendicular permeation, were used to assess how the prepared materials performed as barrier films. Furthermore, testing a subset of these films in an in vitro system mimicking Mg-based transient health monitors indicated that the materials exhibit biofluid barrier properties relevant to extending the operational lifetime of these transient devices. Ultimately, these polymers represent a step towards addressing one of the bottlenecks in the clinical deployment of several emerging technologies.