[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 

