The present invention provides isolated nanosheets each of which includes a plurality of pseudo-polyrotaxanes and which are easily isolated without adhering to each other. The present invention provides an isolated nanosheet including a plurality of pseudo-polyrotaxanes each having one or more first cyclic molecules and a linear molecule included in a cavity or cavities of the first cyclic molecules in a skewered manner, wherein the linear molecules include, as part thereof, first linear molecules each having an ionizable group that ionizes in water or an aqueous solution.

A cation-conducting polymer has two or more repeating units of the following formula ##STR00001##
Owing to the cation-conducting polymer has good physicochemical properties, hydrolytic stability and conductivity, a film formed by coating the liquid cation-conducting polymer can be used as proton exchange membrane to apply in fuel cell system.

A cation-conducting polymer has two or more repeating units of the following formula

##STR00001##

Owing to the cation-conducting polymer has good physicochemical properties, hydrolytic stability and conductivity, a film formed by coating the liquid cation-conducting polymer can be used as proton exchange membrane to apply in fuel cell system.

The present invention provides isolated nanosheets each of which includes a plurality of pseudo-polyrotaxanes and which are easily isolated without adhering to each other. The present invention provides an isolated nanosheet including a plurality of pseudo-polyrotaxanes each having one or more first cyclic molecules and a linear molecule included in a cavity or cavities of the first cyclic molecules in a skewered manner, wherein the linear molecules include, as part thereof, first linear molecules each having an ionizable group that ionizes in water or an aqueous solution.

The present invention discloses sulfonated polyphenylene (phenylene) ether random copolymer, preparation method and application thereof, which has a general chemical formula:

##STR00001## wherein, X is 2 to 5 arylene groups or nitrogen-containing heteroarylene groups; Y is 2 to 5 arylene groups or nitrogen-containing heteroarylene groups, C(CF.sub.3)Ph, C(Ph).sub.2; Z is direct bond, S, C(CF.sub.3).sub.2, C.sub.3H.sub.6, SO.sub.2, CO.sub.2, C(CF.sub.3)Ph, C(Ph).sub.2, 0 to 5 arylene groups or nitrogen-containing heteroarylene groups; R.sub.1 is 0 or more of halogen, NO.sub.2, CN, CF.sub.3, CH.sub.3 or SO.sub.3H; R.sub.2 is 1 to 8 aryl groups or nitrogen-containing heteroaryl groups optionally substituted with 0 to 8 substituents of halogen, NO.sub.2, CN, CF.sub.3, CH.sub.3 or SO.sub.3H; R.sub.3 is 0 to 4 substituents of halogen, NO.sub.2, CN, CF.sub.3, CH.sub.3, SO.sub.3H, aryl or nitrogen-containing heteroaryl; R.sub.4 is 0 or more of halogen, CH.sub.3, NO.sub.2, CN or CF.sub.3, and R.sub.5 is 0 or more of halogen, CH.sub.3, NO.sub.2, CN or CF.sub.3, or 0 to 8 aryl or nitrogen-containing heteroaryl substituted with 0 to 8 substituents of halogen, CH.sub.3, NO.sub.2, CN or CF.sub.3.

Whereby, the polyphenyl polymer has hydrophilic part and dense sulfonic acid side chains, membrane made by the polymer with polyphenyl structure does have strong mechanical properties and maintains good dimensional stability when in contact with water for a long time. Through controlling the polymerization equivalent ratio of Z, the ratio between the hydrophilic and hydrophobic segments can be precisely adjusted.