Interfacial Structures of Trihexyltetradecylphosphonium-bis(mandelato)borate Ionic Liquid Confined between Gold Electrodes
Number of Authors: 5
2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 5, 4976-4987 p.Article in journal (Refereed) Published
Atomistic molecular dynamics simulations have been performed to study microscopic the interfacial ionic structures, molecular arrangements, and orientational preferences of trihexyltetradecylphosphonium-bis(mandelato)borate ([P-6,P-6,P-6,P-14][BM]) ionic liquid confined between neutral and charged gold electrodes. It was found that both [P-6,P-6,P-6,P-14] cations and [BMB] anions are coabsorbed onto neutral electrodes at different temperatures. The hexyl and tetradecyl chains in [P-6,P-6,P-6,P-14] cations lie preferentially flat on neutral electrodes. The oxalato and phenyl rings in [BMB] anions are characterized by alternative parallel perpendicular orientations in the mixed innermost ionic layer adjacent to neutral electrodes. An increase in temperature has a marginal effect on the interfacial ionic structures and molecular orientations of [P-6,P-6,P-6,P-14] [BMB] ionic species in a confined environment. Electrifying gold electrodes leads to peculiar changes in the interfacial ionic structures and molecular orientational arrangements of [p(6,6,414)] cations and [BMB] anions in negatively and positively charged gold electrodes, respectively. As surface charge density increases (but lower than 20 mu C/cm(2)), the layer thickness of the mixed innermost interfacial layer gradually increases due to a consecutive accumulation of [P6,6,614] cations and [BMB] anions at negatively and positively charged electrodes, respectively, before the formation of distinct cationic and anionic innermost layers. Meanwhile, the molecular orientations of two oxalato rings in the same [BMB] anions change gradually from a parallel perpendicular feature to being partially characterized by a tilted arrangement at an angle of 45 from the electrodes and finally to a dominant parallel coordination pattern along positively charged electrodes. Distinctive interfacial distribution patterns are also observed accordingly for phenyl rings that are directly connected to neighboring oxalato rings in [BMB] anions.
Place, publisher, year, edition, pages
2017. Vol. 9, no 5, 4976-4987 p.
trihexyltetradecylphosphonium-bis(mandelato)borate ionic liquid, gold electrodes, atomistic simulations, interfacial structures, molecular arrangements
Nano Technology Materials Engineering
IdentifiersURN: urn:nbn:se:su:diva-141426DOI: 10.1021/acsami.6b14429ISI: 000393848900080PubMedID: 28099800OAI: oai:DiVA.org:su-141426DiVA: diva2:1087009