TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The cyclobutyl moiety is perfluorocyclobutyl moiety.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer blend further comprises nonionic polymer comprising fluoro-elastomer. The first polymer comprises 2 out of 4 aromatic and/or aliphatic polymer segments including segments of formulae (E1(SO2X)d)-D1-Q1-D2 (II) and E2-D3-Q2-D4 (III) connected by linking group to form polymer units of formula -(E2-D3-Q2-D4)j-L1-(E1(SO2X)d-D1-Q1-D2)i- (IV).E1=aromatic-containing moiety;E2=aromatic-containing and/or aliphatic-containing moiety;X=-OH, halo, ester or -NH-S(=O)2-R4;d, i, j= greater than or equal to 1;D1-D4=absent, -O-, -S-, -SO-, -CO-, -SO2-, -NR1H-, NR2- or -R3-;R2=1-125C alkyl, aryl or arylene;R3=1-125C alkylene, perfluoroalkylene or arylene, perfluoroalkyl ether or alkylether;R4=CF3, 1-125C alkyl, perfluoroalkylene or aryl, or E1;Q1, Q2=fluorinated cyclobutyl moiety; andL1=linking group.The second polymer is perfluorosulfonic acid polymer comprising 1 out of 4 sulfonic acid compound including compound of formula (-(CF2-CF2)o-(CF2-CF(-O-(CF2-CF(CF3))a-O-(CF2-CF2)b-SO3H))p-)n (V), or copolymer containing polymerization unit based on perfluorovinyl compound of formula CF2=CF-(OCF2CFX1)m-Or-(CF2)q-SO3H (VI) and tetrafluoroethylene.o=0-10;p= greater than or equal to 1;n=more than 10;a=0-3;b=1-12;m=0-3;q=1-12;r=0-1; andX1=F or CF3.Preferred Composition: The polymer blend comprises (wt.%) first polymer (1-99, preferably 30-70) and second polymer (1-99, preferably 30-70). EXAMPLE - A Nafion 1000(RTM: perfluorosulfonic acid polymer) was poured in 8-inchx8-inch baking dish and dried at 60 degrees C for 16 hours. The obtained perfluorosulfonic acid residue was dissolved in N,N-dimethylacetamide (DMAc) at 60 degrees C for 16 hours to form 20 wt.% solids solution. A perfluorocyclobutane block copolymer (TRJ261, 5g) comprising poly(para-biphenyl-perfluoro-cyclobutane) having molecular weight of 8000 copolymerized with bis(perfluorovinyl ether) of hexafluoro-bisphenol acetone at weight ratio of 2:1 and having number average molecular weight of 28574 was dissolved in methylene chloride (100 mL), heated in oil bath at 400 degrees C, added with chlorosulfonic acid (10 g), stirred magnetically for 30 minutes to obtain purple rubbery polymer precipitates, kept still for 1 hour and decanted off with solvent. The obtained purple rubbery solid was washed with methylene chloride (50 mL), chopped in water (100 mL), boiled in water (2500 mL) for 1 hour, filtered, washed with water and dried to obtain light yellow fibrous polymer (5 g). The obtained yellow sulfonated TRJ261 polymer (10 wt.%) was dissolved in DMAc, pressure-filtered through 5- mu m Teflon(RTM: PTFE) millipore filter, coated onto glass and dried at 80 degrees C for 30 minutes. The obtained film was floated off the glass through immersion in deionized water and air-dried to obtain membrane having water-uptake of 34.28 wt.% at 23 degrees C and 438.6 wt.% at 100 degrees C, and ion exchange capacity of 2.01 milliequivalents hydrogen ion/g. The 10 wt.% solids solution of sulfonated-TRJ261 (1 g) in DMAc (9 g) and 20 wt.% solution of Nafion 1000(RTM: perfluorosulfonic acid polymer) (1 g) in DMAc (4 g) were mixed for 1 hour on roll mill and centrifuged for 5 minutes to remove air bubbles, coated onto glass and dried at 80 degrees C for 30 minutes. The obtained membrane was floated off the glass through immersion in deionized water and air-dried.