resumo
The evidence for surface crystallization in ionic liquids is scarce. The existing reports seem to be contradictory as for its driving forces, since in the two compounds investigated in the literature, the contribution of coloumbic and van der Waals forces is very different. In this work 1-dodecyl-3-methylimidazolium tetrafluoroborate was studied and its surface crystallization characterized by surface tension, ellipsometry and optical microscopy. The results obtained seem to reconcile previous observations, and it was further shown, using the same techniques, that this phenomenon is prevalent in other ionic liquids. MD simulation results illustrate the different possibilities of organization, providing reasonable models to rationalize the experimental observations.
palavras-chave
TENSION; BEHAVIOR; PHASE; TRANSITION; RHEOLOGY; MEDIA
categoria
Chemistry; Physics
autores
Martins, MAR; Carvalho, PJ; Alves, D; Dariva, C; Costa, MC; Ferreira, RAS; Andre, PS; Morgado, P; Pinho, SP; Filipe, EJM; Coutinho, JAP
nossos autores
Maria Rute de Amorim e Sá Ferreira André
Professor Catedrático
Pedro J. Carvalho
Professor AuxiliarGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G4 - Materiais Renováveis e Economia Circular
Projectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)
Projeto de Investigação Exploratória: Pedro Carvalho (IF/00758/2015)
agradecimentos
This work was developed with the scope of the project CICECO - Aveiro Institute of Materials, UID/CTM/50011/2019, Associate Laboratory LSRE-LCM, UID/EQU/50020/2019, and of Instituto de Telecomunicacoes/IT (UID/EEA/50008/2013) - funded by national funds through FCT/MCTES (PIDDAC). M. A. R. M. acknowledges financial support from NORTE-01-0145-FEDER-000006 - funded by NORTE2020 through PT2020 and ERDF, and P. J. C. acknowledges the FCT for the contract IF/00758/2015. A. R. Bastos from UA is acknowledged for help in the ellipsometry measurements. M. C. C. aknowledges FAPESP (2012/05027-1) and CNPq (310272/2017-3) for financial support.