title: A new insight into the nanostructure of alkylammonium alkanoates based ionic liquids in water.
abstract: In this paper, small angle X-ray scattering has been used to study a series of ionic liquids, alkylammonium alkanoates ([N0 0 0 n][CmCO2]), with varying alkyl chain lengths in the cation and the anion. We investigate the behaviour and the structure of such ionic liquids in their neat state, and in binary mixtures with water. To the best of our knowledge, this is the first structural study dealing with the behaviour of propylammonium propanoate [N0 0 0 3][C2CO2], butylammonium propanoate [N0 0 0 4][C2CO2], propylammonium butanoate [N0 0 0 3][C3CO2] and butylammonium butanoate [N0 0 0 4][C3CO2] when mixed in water. Generally, in the ionic liquids containing alkyl chains on both the cation and the anion, the correlation distance and the resulting scattering peak, which signal intermediate range order, are affected equally by both of the chains. The interesting result obtained regarding these systems is that the shift of the pre- and principal peaks with the addition of water depends on the overall molar concentration of the chains and is generally cumulative. Although, for a given sum of cation and anion chain lengths, the shift is reliant on the cation-anion combination in the neat state, it is not the case in their mixtures with water. In some recent papers, it has been reported that with addition of water, the pre-peak position remains constant, but our results show a shift in both pre- and principal Q peaks.
authors.affiliation: Dipartimento di Chimica, Università di Roma, "La Sapienza", P. le Aldo Moro 5, I-00185 Roma, Italy. umme.salma@uniroma1.it.
authors.forename: Umme
authors.initials: U
authors.lastname: Salma
authors.affiliation: Dipartimento di Scienze della Terra, Università di Roma, "La Sapienza", P. le Aldo Moro 5, I-00185 Roma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ballirano
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche - Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8, I-09042 Monserrato, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Usula
authors.affiliation: Dipartimento di Chimica, Università di Roma, "La Sapienza", P. le Aldo Moro 5, I-00185 Roma, Italy. umme.salma@uniroma1.it.
authors.forename: Ruggero
authors.initials: R
authors.lastname: Caminiti
authors.affiliation: QUILL, The Queen's University of Belfast, Stranmillis Road, Belfast, Northern Ireland, UK BT9 5AG.
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Plechkova
authors.affiliation: QUILL, The Queen's University of Belfast, Stranmillis Road, Belfast, Northern Ireland, UK BT9 5AG.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Seddon
authors.affiliation: Dipartimento di Chimica, Università di Roma, "La Sapienza", P. le Aldo Moro 5, I-00185 Roma, Italy. umme.salma@uniroma1.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Gontrani