Aug. 2, 2007  5  US 2007/0179263 A 1  viscosity are those selected from the group consisting of  anions derived from inorganic acids and anions derived from  organic acids, and particularly preferred are anions derived  from inorganic acids.  [0056]  Further preferred are anions being capable of form› ing Lewis acid, for example, PF $_{6 }$ - ,  BF  4  - ,  SbF $_{6 }$ - and the like.  [0057]  In the ionic liquid type functional material of the  present invention, Ry is featured by having an aromatic ring  structure in addition to the above-mentioned basic functional  group Y 1  and the salt Y 2  of the basic functional group.  [0058]  The moiety of aromatic ring structure may be one  having an aromatic ring structure formed by using only  carbon atoms, one having an aromatic ring structure formed  by using carbon atoms and hetero atoms such as nitrogen  atom, sulfur atom or oxygen atom or one having a mono› cyclic structure or polycyclic structure (fused ring).  [0059]  Examples of the moiety of aromatic ring structure  are:  and the like.  [0060]  The presence of those aromatic ring structures is  preferred because enhancement of oxidation resistance and  improvement in a dielectric constant are given to the ionic  liquid type functional material of the present invention.  [0061]  In the ionic liquid type functional material of the  present invention, the presence of the fluorine-containing  ether unit -D- is usually disadvantageous from the viewpoint  of a dielectric constant, but by introducing the aromatic ring  structure, a dielectric constant can be improved.  [0062]  Concretely improvement of a dielectric constant is  particularly preferred in ionic liquid application and solar  cell electrolyte application.  [0063]  Also the presence of the aromatic ring structure is  preferred since interaction (affinity) with various inorganic  compounds, hydrocarbon compounds and polymer com› pounds is high and adsorption property can be improved. In  the ionic liquid type functional material of the present  invention, the presence of the fluorine-containing ether unit  -D- is usually disadvantageous from the viewpoint of  adsorption, but by introducing the aromatic ring structure,  adsorption with various inorganic and organic materials can  be improved. By this improvement of adsorption, the func› tional material can be a material suitable for lubricant  application and the like requiring adhesion to a substrate.  [0064]  The basic functional group Y$^{1 }$or the salt Y 2  of the  basic functional group (hereinafter Y 1  and Y 2  are collec› tively referred to as functional group Y) may be bonded to  the aromatic ring structure as a substituent outside the  aromatic ring structure, or the hetero atom forming the  functional group Y ( cation portion in the case of a salt) may  constitute the aromatic ring at the same time.  [0065]  In the case of the bonding of the functional group  Y to the aromatic ring structure as a substituent, the func› tional group Y may be bonded directly to the carbon atom of  the aromatic ring, or the functional group Y may be bonded  to the carbon atom of the aromatic ring via a bond (spacer)  of divalent organic group.  [0066]  It is preferable that the divalent organic group  which is the bond is selected from divalent hydrocarbon  groups having 1 to 10 carbon atoms, more preferably  divalent alkylene groups having 1 to 5 carbon atoms, par› ticularly preferably methylene or ethylene. Hydrocarbon  groups having a too long chain are not preferred because  oxidation resistance is lowered.  [0067]  Further the functional group Y may be contained as  -Y - in the substituent of the aromatic ring.  [0068]  In the case of forming an aromatic ring structure by  using carbon atom and hetero atom, the above-mentioned  -continued  o.  N  H  N--N  l  11’  ,..-N  N  H  CC N  h.  0.  N  H  O•  N  N  H  0.  N  CX N)  #,  N  oco  ,  #  ~  ~N~,  H  ~  H  N~NH,  lNAN)  S  O  S  0 