Aug. 2, 2007  20  US 2007/0179263 A  1  [0148]  Thus the polymer can be liquefied and a viscosity  can be decreased.  [0149]  Also preferred as the structural unit Al ( or A2) are  those which do not lower characteristics derived from the  structural unit Ml (or M2), for example, oxidation resis› tance, heat resistance, liquidity and low viscosity.  [0150]  From that point of view, it is preferable that the  structural unit Al ( or A2) is a structural unit derived from a  fluorine-containing ethylenic monomer.  [0151]  Preferred as the structural unit derived from a  fluorine-containing ethylenic monomer are those selected  from structural units Al-1 ( or A2-1) derived from fluorine› containing ethylenic monomers having 2 or 3 carbon atoms  and at least one fluorine atom. Those structural units Al-1  ( or A2-1) are preferred because oxidation resistance and heat  resistance can be improved.  [0152]  Concretely there are CF$_{2}$=CF$_{2}$ ,  CF$_{2}$=CFC1,  CH$_{2}$=CF$_{2}$ ,  CFH=CH$_{2}$ ,  CFH=CF$_{2}$ ,  CF$_{2}$=CFCF$_{3}$ ,  CH$_{2}$=CFCF  3 ,  CH$_{2}$=CHCF  3  and the like. Among them,  preferred are tetrafluoroethylene (CF$_{2}$=CF$_{2}$ ) and chlorotri› fluoroethylene (CF $_{2}$=CFC1) because an effect of maintain› ing copolymerizability, oxidation resistance, heat resistance  and chemical resistance is high.  [0153]  The proportions of each structural unit in the  fluorine-containing polymers of the formulae (M-1) and  (M-2) are optionally selected depending on structures of the  structural units Ml and M2, intended functions and appli› cations. The structural units Ml ( or M2) and Al ( or A2) are  contained in amounts of preferably from 30 to 100% by  mole and from  O  to 70% by mole, respectively, more  preferably from 40 to 100% by mole and from  O  to 60% by  mole, especially preferably from 60 to 100% by mole and  from  O  to 40% by mole, further preferably from 70 to 100%  by mole and from  O  to 30% by mole.  [0154]  The number average molecular weight of the fluo› rine-containing polymers of the formulae (M-1) and (M-2)  is from 500 to 1,000,000, preferably from 1,000 to 100,000,  more preferably from 1,000 to 50,000, particularly prefer› ably from 2,000 to 20,000.  [0155]  If the molecular weight is too low, there is a case  where there arises a problem that heat resistance is lowered  or mechanical properties are lowered. Also a too high  molecular weight is not preferred because there is a possi› bility of increasing a viscosity.  [0156]  The aromatic compound of the formula (1) and the  fluorine-containing polymers of the formulae (M-1) and  (M-2) of the present invention have various properties and  functions as mentioned supra and can be used alone or in a  mixture with other components as the ionic liquid type  functional material. Embodiments thereof are optionally  selected depending on intended functions and applications.  [0157]  Examples of the ionic liquid type functional mate› rial are, for instance, ionic liquid, electrolyte for solar cell,  lubricant, acid-removing agent, actuator material and the  like.  [0158]  Other components which can be blended may be  optionally selected depending on intended functional mate› rial. For example, in the case of using as a lubricant and  actuator material, an organic acid or inorganic acid may be  blended, and in the case of an electrolyte of solar cell, an  organic solvent or inorganic acid may be blended. Also in  the case of using as an ionic liquid, an other ionic liquid or  organic solvent may be blended.  [0159]  The above-mentioned organic acid and inorganic  acid include both of Br0nsted acids releasing H+ and Lewis  acids not releasing H+.  [0160]  There may be used an optional acid as the above› mentioned acid. Examples of the Br0nsted acid releasing H+  are inorganic acids such as tetrafluoroboric acid, tungstic  acid, chromic acid, hexafluorophosphoric acid, perchloric  acid, hexafluoroarsenic acid, nitric acid, sulfuric acid, phos› phoric acid, hydrofluoric acid, hydrochloric acid, hydrobro› mic acid, hydriodic acid and thiocyanic acid; organic acids  such as trifluoromethanesulfonic acid, pentafluoroethane› sulfonic acid, heptafluoropropylsulfonic acid, bis(trifluo› romethanesulfonyl)-imide, acetic acid, trifluoroacetic acid,  propionic acid, benzenesulfonic acid, toluenesulfonic acid,  n-hexanesulfonic acid, n-octylsulfonic acid, cetylsulfonic  acid, p-chlorobenzenesulfonic acid, phenolsulfonic acid,  4-nitrotoluene-2-sulfonic  acid,  2-sulfobenzoic  acid,  nitrobenzenesulfonic acid, sulfosuccinic acid and sulfoseba› cic acid; and the like. Other examples are acrylic acid,  methacrylic acid, styrene having carboxylic acid in its side  chain, styrene having sulfonic acid in its side chain, solid  polymer acids such as a perfluorosulfonic acid polymer  having sulfonic acid in its side chain represented by  NAFFION (trademark of DuPont), perfluorocarboxylic acid  polymer having carboxylic acid in its side chain represented  by FLEMION (trademark of Asahi Glass Co., Ltd.), per› fluorophosphoric acid polymer having phosphoric acid in its  side chain and perfluoroimide polymer having sulfonyl  imide in its trunk chain or side chain.  [0161]  Examples of the Lewis acid not releasing H+ are  inorganic acids such as oxides or halides (fluorides, chlo› rides, bromides, iodides) of boron, aluminum, silica and  transition metals, for example, molybdenum, tungsten, anti› mony, chromium, titanium, cobalt, iron, manganese, nickel,  vanadium, tantalum, osmium, copper and zinc, and organic  acids such as m- or p-nitrotoluene, nitrobenzene, p-nitrof› luorobenzene,  p-nitrochlorobenzene,  2,4-dinitrotoluene,  2,4-dinitrofluorobenzene, 2,4,6-trinitrotoluene and 2,4,6- trichloro benzene.  [0162]  Those acids may be blended to the aromatic com› pounds of the formula (1) and the fluorine-containing poly› mers of the formulae (M-1) and (M-2). In the case of the  aromatic compounds of the formula (1), blending of the acid  is advantageous for uses as functional materials for lubricant  and ionic liquid, and in the case of the fluorine-containing  polymers of the formulae (M-1) and (M-2), a viscosity of the  polymer is decreased by blending of the acid, and the  obtained polymer of a salt having a low viscosity is suitable  as an ionic liquid polymer as well as an electrolyte for solar  cell.  [0163]  Also a composition containing a high molecular  weight organic or inorganic acid in the form of solid and the  compound or polymer of the present invention is a material  suitable for an actuator.  [0164]  The aromatic compound of the formula (1) or the  fluorine-containing polymer of the formula (M-1) or (M-2)  and an acid can be mixed at an optional ratio. It is preferable 