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Physical Vapor Deposition of [EMIM][Tf 2 N]: A New Approach to the Modification of Surface Properties with Ultrathin Ionic Liquid Films
Author(s) -
Cremer Till,
Killian Manuela,
Gottfried J. Michael,
Paape Natalia,
Wasserscheid Peter,
Maier Florian,
Steinrück HansPeter
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800300
Subject(s) - ionic liquid , x ray photoelectron spectroscopy , physical vapor deposition , evaporation , vacuum deposition , bilayer , layer (electronics) , condensation , thermal stability , contact angle , materials science , ultra high vacuum , vacuum evaporation , substrate (aquarium) , chemical engineering , analytical chemistry (journal) , deposition (geology) , chemical vapor deposition , thin film , chemistry , nanotechnology , organic chemistry , membrane , oceanography , engineering , biology , paleontology , biochemistry , thermodynamics , catalysis , physics , sediment , geology , composite material
Ultrathin films of the ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][Tf 2 N], are prepared on a glass substrate by means of an in situ thermal‐evaporation/condensation process under ultrahigh‐vacuum conditions. By using X‐ray photoelectron spectroscopy (XPS), it is demonstrated that the first layer of the IL film grows two dimensionally, followed by the three‐dimensional growth of successive layers. The first molecular layer consists of a bilayer, with the [EMIM] + cations in contact to the surface and the [Tf 2 N] − anions at the vacuum side. The ultrathin IL films are found to be stable under ambient conditions.