Biodegradable Polycarbonate Iongels for Electrophysiology Measurements

Abstract

In recent years, gels based on ionic liquids incorporated into polymer matrices, namely iongels, have emerged as long-term contact media for cutaneous electrophysiology. Iongels possess high ionic conductivity and negligible vapor pressure and can be designed on demand. In spite of the extensive efforts devoted to the preparation of biodegradable ionic liquids, the investigations related to the preparation of iongels based on biodegradable polymers remain scarce. In this work, biodegradable polycarbonate-based iongels are prepared by ring-opening polymerization of N-substituted eight ring membered cyclic carbonate monomers in the presence of imidazolium lactate ionic liquid. Our iongels are able to take up 10–30 wt % of ionic liquid and become softer materials by increasing the amount of free ionic liquid. Rheological measurements showed that the cross-over point between the storage modulus G′ and loss modulus G″ occurs at lower angular frequencies when the loading of free ionic liquid increases. These gels are able to take up to 30 wt % of the ionic liquid and the ionic conductivity of these gels increased up to 5 × 10−4 S·cm−1 at 25 °C as the amount of free ionic liquid increased. Additionally, we assess the biodegradation studies of the iongels by immersing them in water. The iongels decrease the impedance with the human skin to levels that are similar to commercial Ag/AgCl electrodes, allowing an accurate physiologic signals recording. The low toxicity and biodegradability of polycarbonate-based iongels make these materials highly attractive for cutaneous electrophysiology applications.

3D Printable and Biocompatible Iongels for Body Sensor Applications

“…Interestingly, these values were much higher than those reported by Isik et al for [Ch] [Lac]-based iongels, using a covalently crosslinked polymer host (ionic conductivity values at 60 °C range from 1 × 10 -5 to 1 × 10 -3 S cm -1 ). [8] Others authors have also reported ionic conductivity values at 60°C of around 10 -3 S cm -1 for iongels based on polycarbonates, [34] gel composed by a fluorocarbon elastomer and a fluorine-rich ionic liquid [35] and poly vinylchloride. [36] Therefore, these results suggest that the dynamic nature of our supramolecular iongels can probably facilitate the ions mobility inside the polymer network, boosting the ionic conductivity.…”

Novel Chemical Cross-Linked Ionogel Based on Acrylate Terminated Hyperbranched Polymer with Superior Ionic Conductivity for High Performance Lithium-Ion Batteries

“…However, some disadvantages include low ionic conductivities and narrow electrochemical windows, especially, the flammability and toxicity of the volatile solvents limits its application [6,7,8]. Ionogels, based on ionic liquids with three-dimensional networks, are promising new GPE materials and have received considerable attention owing to their attractive properties such as high ion mobility, high thermal stability, safety, and nonflammability [9,10,11,12,13,14,15]. These characteristics of ionogels allow them to be considered as attractive candidates for many applications in energy storage devices, actuators, and flexible electronics [16,17,18,19,20].…”

Polycarbonate/Titania Hybrid Films with Localized Photo-Induced Magnetic-Phase Transition

“…The absorption bands at 1402–1450 cm −1 , 2857–2925 cm −1 , 1240 cm −1 , 1530 cm −1 , and 1740 cm −1 were assigned to the C–H bending, C–H stretching, C–O stretching, N–H bending, and C=O stretching of polycarbonates, respectively. The peak attributed to the main chain cannot be observed before and after UV irradiation [ 36 , 37 , 38 , 39 ]. This phenomenon is attributed to the absorption of the partial oxygen deficiency state of titania and not the coloration due to the modification of the polycarbonate matrix.…”