Carbonization of polymers of intrinsic microporosity to microporous heterocarbon: Capacitive pH measurements

Abstract

A nitrogen-containing polymer of intrinsic microporosity (PIM-EA-TB-H2 ; nitrogen adsorption surface area 846 m 2 g −1) is vacuum carbonized at 700 • C and thereby directly without post-treatment converted into a microporous heterocarbon (cPIM; N2 adsorption surface area 425 m 2 g −1). Nitrogen functional-ities in the polymer backbone are retained in the heterocarbon and appear responsible for unusual time-, electrolyte-, and pH-dependent properties. Electrochemical characterization suggests a high specific capacitance (typically 50 F g −1) but only after prolonged immersion in aqueous HClO4. The timedependent increase in capacitance during immersion is assigned to slow hydration and ingress of HClO4 into hydrophobic micropores (H2 SO4 or H3 PO4 are more hydrophilic and much less effective). Once hydrated, the microporous heterocarbon exhibits pH-dependent capacitance "switching" over a wide pH range and analytical applications as "capacitive" pH sensor are proposed. .

Thin film composite membranes based on a polymer of intrinsic microporosity derived from Tröger's base: A combined experimental and computational investigation of the role of residual casting solvent

“…In this work, thin film composite membranes were developed using PIM-EA(H2)-TB, a simple modification of the much studied polymer PIM-EA-TB, lacking two methyl groups on the EA unit [15]. The properties of PIMs-based membranes strongly depend on their preparation history (casting solvent, thermal treatment, ageing, etc.).…”

Polymers of Intrinsic Microporosity in Triphasic Electrochemistry: Perspectives

“…[60] It was shown that the careful carbonization of PIM-EA-TB produces a heterocarbon without loss of morphology or of cumulative pore volume. [61,62] The black product clearly exhibited Raman signatures for graphitic carbon, but the molecularly rigid backbone of the PIM (which is known to lead to high temperature tolerance or cross-linking for PIMs [63] ) must have remained intact with also nitrogen being retained (at least at lower carbonization temperatures). Also PIM-1 was reported to carbonize to novel microporous water filtration membranes.…”

One-step preparation of microporous Pd@cPIM composite catalyst film for triphasic electrocatalysis

“…In related studies, a nano-particulate heterocarbon material with slow ingress of aqueous electrolyte and with pH-dependent capacitance was obtained [14] and nano-platinum was formed embedded in the microporous heterocarbon [15]. Here, nano-palladium is embedded into carbonised PIM-EA-TB (or Pd@cPIM).…”