Tacticity Influence on the Electrochemical Reactivity of Group Transfer Polymerization-Synthesized PTMA

Abstract

Spectroscopic, thermal, and electrochemical characterization results are presented for the redox active polymer poly(2,2,6,6-tetramethyl-1-piperinidyloxy-4-yl methacrylate) or PTMA, synthesized by group transfer polymerization (GTP), and its precursors 4-hydroxy-tetramethylpiperidine-N-oxyl (HO-TEMPO) and 4-methacryloyloxy-tetramethylpiperidine-N-oxyl (MO-TEMPO). DSC analysis of synthesized PTMA showed that the glass transition temperature (T(g)) of the polymer structure occurs at 155 °C, corroborated by dynamic mechanical analysis (DMA), which is higher when compared with T(g) data for PTMA synthesized by other methods. Also, the amount of radical species present in PTMA synthesized by GTP reactions (100%) is higher than the values typically upon synthesizing PTMA by radical polymerization. Electrochemical and spectroelectrochemical-electron spin resonance studies in acetonitrile revealed two redox events in the PTMA polymer, one of which is reversible, accounting for ca. 80% of the spins in the polymer and giving rise to the battery behavior. The other redox event is irreversible, accounting for the remaining ca. 20% of spins, which has not previously been reported. These two redox events are linked to a structural property associated with the tacticity of the polymer, where the reversible feature (responsible for cathode behavior) is the dominant species. This corresponds to a number of isotactic domains of the polymer (determined by high temperature (1)H NMR). The second feature accounts for the three-line impurity observed in the ESR, which has been reported previously but poorly explained, associated to the number of heterotactic/syndiotactic triads.

On the Environmental and Electrical Bias Stability of Radical Polymer Conductors in the Solid State

“…On the other hand, only recently was it established that these types of reactions can also occur in a rather rapid manner in solid‐state organic electronic applications . Specifically, the model radical polymer, poly(2,2,6,6‐tetramethylpiperidinyloxy methacrylate) (PTMA), is an extraordinarily transparent material and can be easily synthesized in large batches . Furthermore, it has an electrical conductivity and a hole mobility in the solid‐state that are on par with common pristine (i.e., not doped) π ‐conjugated semiconductors (e.g., P3HT) .…”

“…[29][30][31][32][33][34] Specifi cally, the model radical polymer, poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA), is an extraordinarily transparent material and can be easily synthesized in large batches. [ 29,[35][36][37][38] Furthermore, it has an electrical conductivity and a hole mobility in the solid-state that are on par with common pristine (i.e., not doped) π -conjugated semiconductors (e.g., P3HT). [ 29,30 ] However, due to the nascent nature of the solid-state conducting radical polymer fi eld, the quantifi cation of the stability of the electrical performance of radical polymers, in particular PTMA, in the solid-state has not been established or even discussed in detail.…”

Nanopatterning of Stable Radical Containing Block Copolymers for Highly Ordered Functional Nanomeshes

“…Because of similar block ratios, spectra (both concerning peak occurrence and intensities) are almost identical. NMR measurements of the polymers after reduction with phenlyhydrazine (Figure SI-2in the Supporting Information) also shows the absence of impurities and successful polymerization due to peaks from both the PtBMA (OC(CH 3 ) 3 at 1.33 ppm) and PTMA (OCH(CH 2 ) 2 at 4.82 ppm) homopolymer blocks 31. Cyclic voltammetry (Figure SI-3in the Supporting Information) shows the redox peak at 0.465 V vs.Ag/AgNO 3 .…”

A Methoxyamine‐Protecting Group for Organic Radical Battery Materials—An Alternative Approach

“…Polymers with pendant nitroxide moieties have previously been synthesized by various polymerization techniques, including ring‐opening metathesis polymerization (ROMP), ring‐opening polymerization, anionic, group transfer, and radical polymerization . While radical polymerization is generally the most widely employed polymerization technique, owing to its ease of use and straight forward reaction conditions, nitroxide‐bearing monomers cannot be directly polymerized because of the nitroxide's radical scavenging nature and inhibition effect on free radical chain propagation.…”