  Ionic liquids (ILs) feature a tailorable and wide range of structural,
chemical and electronic properties that make this class of materials suitable
to a broad variety of forefront applications in next-generation electronics.
Yet, their intrinsic complexity call for special attention and experimental
probes have still limitations in unraveling the interactions occurring both in
the bulk IL and at the interface with the solid substrates used to build the
devices. This works provides an atomistic insight into these fundamental
interactions by molecular modeling to complement the information still not
accessible to experiments. In particular, we shed some light on the nature of
the chemical bonding, structure, charge distribution and dipolar properties of
a series of alkyl-imidazolium-based ILs by a synergy of classical and
first-principles molecular dynamics simulations. Special emphasis is given to
the crucial issue of the hydrogen bond network formation ability depending
either on the nature of the anion or on the length of the alkyl chain of the
cation. The hydrogen bond strength is a fundamental indicator of the cohesive
and ordering features of the ILs and, in this respect, might be exploited to
foster a different behaviour of the IL used a bulk medium or when used in
electronic devices.
