substrate, in order to enhance adhesion, there is employed a method of introducing a functional group such as hydroxyl or carboxyl, or converting to a salt of carboxylic acid. For example, with respect to a lubricant to be used as a magnetic recording medium, there are a report that an ester compound of perfluoro polyether having hydroxyl or carboxyl is used as a lubricant (JP5-l 94970A) and a report that an amine salt compound of perfluoro polyether having carboxylic acid group at an end or both ends thereof is used as a lubricant (JP5-143975A, JP2001-216625A). However acidity of car› boxylic acid at an end of perfluoro polyether is higher than that of usual hydrocarbon carboxylic acid. Therefore in the case of ester, hydrolysis easily occurs and there is a problem with long-term stability. Also even in the case of using an amine salt compound of perfluoro polyether having carboxy› lic acid at an end thereof, since acidity of the carboxylic acid at an end of perfluoro polyether is strong, free carboxylic acid influences a substrate. Therefore an excessive amount of aromatic amine must be contained in the presence of the salt, and there is a problem with long-term stability due to dropping out and vaporization of the low molecular weight aromatic amine from a substrate. 

[0177] When the aromatic compound of the present inven› tion is used as a lubricant, the lubricant must be in the form of a composition containing the aromatic compound and an acid because the compound itself has basicity and has an adverse effect on a substrate. However since the fluorine› containing ether chain of the compound of the present invention has basicity, the compound can be used as a lubricant component in the form of a composition containing a weak acid having less effect on a substrate, and there are such effects that long-term stability is high and further adhesion to a substrate is excellent since the compound contains an aromatic ring structure. 

[0178] Among the compounds of the present invention, those containing basic functional group is easily liquefied by mixing with a liquid acid, and is liquefied even if the liquid acid is not more than a neutral point. Thus the composition containing a liquid acid and the aromatic compound of the present invention can be a compound having a low viscosity and being suitable as an ionic liquid. 

(Acid-removing Agent) 

[0179] While importance is attracted to environmental problems, there arises a problem with disposal of waste water and waste solvent resulting from synthesis of chemical substances. Especially when waste water contains acid com› ponents such as an organic acid, phosphoric acid, and oxides or halides of osmium or tin having a great influence on environment, treatment of an acid is not considered to have been completed only by neutralization, and it is necessary to remove an acid itself from waste water. For removing an acid from waste water, there is a case where an anionic polymer is used as an acid-removing agent from the view› point of easy separation from water and easy recycling. However there are few kinds of anionic polymers having good separability from water and oxidation resistance thereof is not always good. Therefore the number of recy› clings is limited. Further in a process for removing an acid from waste water and a process for removing an acid for recycling, efficiency is not always good because those processes are liquid-solid reaction. The aromatic compound itself of the present invention containing a fluorine-contain- 

ing ether is a liquid, and therefore a process for removing an acid is liquid-liquid reaction and reaction efficiency is high. Also when the fluorine-containing ether chain is short, there is a case where the compound of the present invention is dissolved in an acidic aqueous solution, and thereby making it difficult to separate an acid. Therefore an aromatic com› pound having a long fluorine-containing ether chain is preferred. Further since the aromatic compound of the present invention has a high boiling point, there is no fear of evaporation and recycling is easy. 

(Actuator) 

[0180] An actuator is expected to be applied to an artificial muscle and micro robot, and is a material changing its form by external stimulation such as heat, light and electricity. Among actuators, a material in which a polymer electrolyte gel undergoes swelling and shrinkage in response to an electric signal is highly expected to be put into practical use because an electric signal can be easily controlled (Science and Industry, 72(4), pp. 162 to 167 (1998)). 

[0181] It is preferable that such an actuator shows a larger change in response to an electric potential because an intended deformation is made by a smaller electric potential. Currently solid polymer acid materials such as perfluoro› sulfonic acid membrane and perfluorocarboxylic acid mem› brane subjected to swelling with water are used as an actuator material, and studies are made to increase a degree of deformation in response to an electric potential. 

[0182] In the present invention, for example, when the compound of the present invention having basic functional group or the polymer of the present invention is added to a solid polymer acid such as perfluorosulfonic acid membrane or perfluorocarboxylic acid membrane subjected to swelling with water, there is an effect of increasing an amount of change in its form as compared with the case of not adding the compound or polymer. 

[0183] The functional material of the present invention, as mentioned above, can be used or mixed in the form ofliquid or in the form of solid. Further the functional material can be formed into a solid membrane. 

[0184] For forming the functional material into a solid membrane, known optional methods, for example, casting, impregnation and heat press are used. 

[0185] In the case of forming the solid membrane, com› binations of the acid and the compound or polymer are 

(i) impregnation of the solid acid with the liquid aromatic compound having fluorine-containing ether according to the present invention, 

(ii) impregnation of the liquid acid with the solid aromatic polymer having fluorine-containing ether according to the present invention, 

(iii) composite of the solid aromatic polymer having fluo› rine-containing ether according to the present invention and the solid acid, 

(iv) impregnation of an other solid membrane with a com› position containing an acid and the compound or polymer, and the like. 

[0186] The second of the present invention is a novel aromatic compound having a fluorine-containing ether chain. 

