Influence of Anion and Crosslink Density on the Ionic Conductivity of 1,2,3‐Triazolium‐Based Poly(ionic liquid) Polyester Networks

• Published in: Macromolecular chemistry and physics 2017-11, Vol.218 (21), p.n/a
• Main Authors: Nguyen, Anh, Rhoades, Taylor C., Johnson, R. Daniel, Miller, Kevin M.
• Format: Article
• Language: English
• Subjects: 1,2,3‐triazolium; Addition polymerization; Chain dynamics; Conductivity; Crosslinking; Density; Ion currents; ionic conductivity; Ionic liquids; Ions; Michael addition; poly(ionic liquid)
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201700337

Covalently crosslinked, 1,2,3‐triazolium‐containing poly(ionic liquid) networks are prepared using Michael addition polymerization. Crosslink density and counteranion are varied in order to decipher the relationships between poly(ionic liquid) (PIL) structure and their thermal, mechanical, and conductive properties. An increase in acrylate concentration leads to a higher crosslink density, as reflected by an increase in the differential scanning calorimetry Tg, dynamic mechanical analyzer E′, and a decrease in the ionic conductivity. Most notable with variable counteranion PILs is that analysis of the ionic conductivity curves reveals a common “crossover” point at ≈85 °C (same acrylate:acetoacetate ratio). Below this crossover temperature, the ionic conductivity appears to be more dependent upon network/polymer chain dynamics. Above 85 °C, the conductivity correlates best with the size of the counteranion. All of the PILs reported here exhibit good ionic conductivities (10−6 to 10−8 S cm−1@25 °C, 30% RH), supporting the notion that 1,2,3‐triazolium‐containing PILs represent a vastly underrated electroactive material platform. A series of 1,2,3‐triazolium‐containing poly(ionic liquid) networks with variable counteranion or crosslink density are prepared and their thermal, mechanical, and conductive properties are presented. A unique “crossover” temperature is observed in the ionic conductivity at ≈85 °C with variable counteranion. Below this temperature conductivity is driven primarily by Tg however, at higher temperatures, ion size appears to be the most important factor.