S1 Supporting Information: Investigation of Confined Ionic Liquid in Nanostructured Materials by a Combination of SANS, Contrast-Matching SANS and Nitrogen Adsorption Konstantinos L. Stefanopoulos,* ,† George E. Romanos, † Olga C. Vangeli, † Konstantina Mergia, ‡ Nick K. Kanellopoulos, † Alexandros Koutsioubas § and Didier Lairez § † Institute of Physical Chemistry and ‡ Institute of Nuclear Technology and Radiation Protection, NCSR “Demokritos”, 15310 Ag. Paraskevi Attikis, Athens, Greece § Laboratoire Léon Brillouin, CEA/CNRS UMR 12, CEA-Saclay, 91191 Gif-sur-Yvette cedex, France * stefan@chem.demokritos.gr 1. Preparation of 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF 6 - ] a) Synthesis of 1-butyl-3-methylimidazolium chloride, [bmim][Cl - ] The synthesis procedure was based on published data with minor changes. 1-3 To (23.4 mmol) of 1-methyl-imidazole, (28.7 mmol, 1.2 eq) of 1-chlorobutane was added in a round bottomed flask fitted with a reflux condenser and the mixture was allowed under stirring to react in reflux conditions and N 2 atmosphere for 48 hr. The viscous yellow-orange liquid obtained was washed with EtOAc (2x30 ml) and dried under vacuum at 363 K to give 3.9 g (95% w/w) of 1-butyl-3-methylimidazolium chloride. b) Ion exchange step The ion exchange step was based on published data with slight changes. 3-5 (1.05 g, 6.04 mmol) of 1-butyl-3-methylimidazolium chloride were dissolved in 6 ml CH 2 Cl 2 and to the solution it was added (1.14 g, 6.78 mmol) of sodium hexafluorophoshate in 4 ml CH 3 CN.