Zeolitic imidazolate framework-methacrylate composite monolith characterization by inverse gas chromatography

• Preparation of zeolitic imidazolate framework-8-methacrylate monolith composite capillary columns for gas chromatographic applications.
• Evaluation of the thermodynamic parameters of the prepared monoliths using inverse gas chromatography technique (IGC) using non-polar probes.
• Evaluation of the acid-base characteristics of the prepared monoliths using polar probes.
• Estimation of the Flory-Huggins interaction parameters between probes and studied monoliths.

Thermodynamic characterization of butyl methacrylate-co-ethylene dimethacrylate neat monolith and zeolitic imidazolate framework-8 incorporated with butyl methacrylate-co-ethylene dimethacrylate composite monolith were studied using inverse gas chromatography at infinite dilution under 1 MPa column pressure and various column temperatures. The free energy of adsorption (ΔGA), enthalpy of adsorption (ΔHA) and entropy of adsorption (ΔSA) were determined using a series of n  -alkanes. The dispersive component of surface energy (γSD) was estimated by Dorris-Gray and Schultz et al. methods. The composite monolith showed a more energetic surface than the neat monolith. The acidic, KA, and basic, KD, parameters for both materials were estimated using a group of polar probes. A basic character was concluded with more basic behavior for the neat monolith. Flory-Huggins parameter, χ, was taken as a measure of miscibility between the probes with the low molecular weight and the high molecular weight monolith. Inverse gas chromatography provides a better understanding of the role of incorporated zeolitic imidazolate framework (ZIF-8) into the polymer matrix in its monolithic form.