A novel side-chain polypseudorotaxanes P4VBVBu/CB[7] was synthesized from poly-N-n-butyl-N'-(4-vinylbenzyl)-4,4'-bipyridinium bromide chloride (P4VBVBu) and cucurbit [7]uril (CB[7]) in water by simple stirring at room temperature. CB[7] beads are localized on viologen units in side chains of polypseudorotaxanes as shown by H-1 NMR, IR, XRD, and UV-vis studies, and it is considered that the hydrophobic and charge-dipole interactions are the driving forces. TGA data show that thermal stability of the polypseudorotaxanes increases with the adding of CB[7] threaded. DLS data show that P4VBVBu and CB[7] could form polypseudorotaxanes, and the average hydrodynamic radius of the polypseudorotaxanes increases with increasing the concentration of CB[7]. The typical cyclic voltammograms indicate that the oxidation reduction characteristic of P4VBVBu is remarkably affected by the addition of CB[7] because of the formation of polypseudorotaxanes and the shielding effects of CB[7] threaded on the viologen units of polypseudorotaxanes. With the increase of the concentration of KBr or K2SO4, the formation of the polypseudorotaxanes was inhibited due to the shielding effects of both Br- or SO42- to viologen ion and K+ to CB[7] by UV-vis. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2135-2142, 2010