The controlled cationic polymerization of isobutylene (IB) initiated by H2O as initiator and TiCl4 as coinitiator was carried out in n-Hexane/CH2Cl2 (60/40, v/v) mixture at -40 degrees C in the presence of N,N-dimethylacetamide (DMA). Polyisobutylene (PIB) with nearly theoretical molecular weight (M-n = 1.0 x 10(4) g/mol), polydispersity (M-w/M-n) of 1.5 and high content (87.3%) of reactive end groups (tert-Chlorine and a-double bond) was obtained. The Friedel-Crafts alkylation of triphenylamine (TPA) with the above reactive PIB was further conducted at different reactions, such as [TPA]/[PIB], solvent polarity, alkylation temperature, and time. The resultant PIBs with arylamino terminal group were characterized by H-1 NMR, UV, and GPC with RI/UV dual detectors. The experimental results indicate that alkylation efficiency (A(eff)) increased with increases in [TPA]/[PIB], reaction temperature, and reaction time and with a decrease in solvent polarity. The alkylation efficiency could reach 81.0% at 60/40(v/v) mixture of n-Hex/CH2Cl2 with [TPA]/[PIB] of 4.49 at 50 degrees C for 54 h. Interestingly, the synthesis of PIB with arylamino terminal group could also be achieved in one pot by combination of the cationic polymerization of IB initiated by H2O/TiCl4/DMA system with the successive alkylation by further introduction of TPA. Mono-, di- or tri-alkylation occurred experimentally with different molar ratio of [TPA]/[PIB]. (C) 2007 Wiley Periodicals, Inc.