title: Immersion Calorimetry: Molecular Packing Effects in Micropores.
abstract: Repeated and controlled immersion calorimetry experiments were performed to determine the specific surface area and pore-size distribution (PSD) of a well-characterized, microporous poly(furfuryl alcohol)-based activated carbon. The PSD derived from nitrogen gas adsorption indicated a narrow distribution centered at 0.57±0.05 nm. Immersion into liquids of increasing molecular sizes ranging from 0.33 nm (dichloromethane) to 0.70 nm (α-pinene) showed a decreasing enthalpy of immersion at a critical probe size (0.43-0.48 nm), followed by an increase at 0.48-0.56 nm, and a second decrease at 0.56-0.60 nm. This maximum has not been reported previously. After consideration of possible reasons for this new observation, it is concluded that the effect arises from molecular packing inside the micropores, interpreted in terms of 2D packing. The immersion enthalpy PSD was consistent with that from quenched solid density functional theory (QSDFT) analysis of the nitrogen adsorption isotherm.
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia.
authors.forename: S Hadi
authors.initials: SH
authors.lastname: Madani
authors.affiliation: Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica, Universidad de Alicante, Apartado 99, E-03080, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Silvestre-Albero
authors.affiliation: School of Chemical Engineering, University of Adelaide, Adelaide, SA, 5005, Australia.|School of Science, Loughborough University, Leicestershire, LE11 3TU, UK).
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Biggs
authors.affiliation: Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica, Universidad de Alicante, Apartado 99, E-03080, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez-Reinoso
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia. Phillip.Pendleton@unisa.edu.au.|Sansom Institute, University of South Australia, Adelaide, SA, 5001, Australia. Phillip.Pendleton@unisa.edu.au.
authors.forename: Phillip
authors.identifier: http://orcid.org/0000-0003-1031-8170
authors.initials: P
authors.lastname: Pendleton
keywords: adsorption; immersion calorimetry; molecular packing; nitrogen; pore size distribution