title: Liquid-Phase Exfoliation of Graphite into Single- and Few-Layer Graphene with α-Functionalized Alkanes.
abstract: Graphene has unique physical and chemical properties, making it appealing for a number of applications in optoelectronics, sensing, photonics, composites, and smart coatings, just to cite a few. These require the development of production processes that are inexpensive and up-scalable. These criteria are met in liquid-phase exfoliation (LPE), a technique that can be enhanced when specific organic molecules are used. Here we report the exfoliation of graphite in N-methyl-2-pyrrolidinone, in the presence of heneicosane linear alkanes terminated with different head groups. These molecules act as stabilizing agents during exfoliation. The efficiency of the exfoliation in terms of the concentration of exfoliated single- and few-layer graphene flakes depends on the functional head group determining the strength of the molecular dimerization through dipole-dipole interactions. A thermodynamic analysis is carried out to interpret the impact of the termination group of the alkyl chain on the exfoliation yield. This combines molecular dynamics and molecular mechanics to rationalize the role of functionalized alkanes in the dispersion and stabilization process, which is ultimately attributed to a synergistic effect of the interactions between the molecules, graphene, and the solvent.
authors.affiliation: Institut de Science et d'Ingeńierie Supramolećulaires (ISIS) and International Center for Frontier Research in Chemistry (icFRC), Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS) , 8 alleé Gaspard Monge, 67000 Strasbourg, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Haar
authors.affiliation: Cambridge Graphene Centre, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Matteo
authors.initials: M
authors.lastname: Bruna
authors.affiliation: Laboratory for Chemistry of Novel Materials, Center for Research in Molecular Electronics and Photonics, University of Mons , Place du Parc 20, 7000 Mons, Belgium.
authors.forename: Jian Xiang
authors.initials: JX
authors.lastname: Lian
authors.affiliation: Cambridge Graphene Centre, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Flavia
authors.initials: F
authors.lastname: Tomarchio
authors.affiliation: Laboratory for Chemistry of Novel Materials, Center for Research in Molecular Electronics and Photonics, University of Mons , Place du Parc 20, 7000 Mons, Belgium.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Olivier
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR), Istituto per la Microelettronica e i Microsistemi (IMM) Sede di Bologna , Via Gobetti 101, 40129 Bologna, Italy.|Dipartimento di Chimica "G. Ciamician", Università di Bologna , Via Selmi 2, 40126 Bologna, Italy.
authors.forename: Raffaello
authors.initials: R
authors.lastname: Mazzaro
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR), Istituto per la Microelettronica e i Microsistemi (IMM) Sede di Bologna , Via Gobetti 101, 40129 Bologna, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Morandi
authors.affiliation: Institut de Science et d'Ingeńierie Supramolećulaires (ISIS) and International Center for Frontier Research in Chemistry (icFRC), Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS) , 8 alleé Gaspard Monge, 67000 Strasbourg, France.
authors.forename: Joseph
authors.initials: J
authors.lastname: Moran
authors.affiliation: Cambridge Graphene Centre, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Ferrari
authors.affiliation: Laboratory for Chemistry of Novel Materials, Center for Research in Molecular Electronics and Photonics, University of Mons , Place du Parc 20, 7000 Mons, Belgium.
authors.forename: David
authors.initials: D
authors.lastname: Beljonne
authors.affiliation: Institut de Science et d'Ingeńierie Supramolećulaires (ISIS) and International Center for Frontier Research in Chemistry (icFRC), Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS) , 8 alleé Gaspard Monge, 67000 Strasbourg, France.
authors.forename: Artur
authors.initials: A
authors.lastname: Ciesielski
authors.affiliation: Institut de Science et d'Ingeńierie Supramolećulaires (ISIS) and International Center for Frontier Research in Chemistry (icFRC), Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS) , 8 alleé Gaspard Monge, 67000 Strasbourg, France.
authors.forename: Paolo
authors.initials: P
authors.lastname: Samorì