Modeling of polystyrene (PS) with various stereosequences in gamma-cyclodextrin (gamma-CD) channels has been conducted and it was found that only isotactic PS stereoisomers can fit into the y-CD cavity. Thus, based on the modeling of stereoisomeric polystyrenes in narrow gamma-CD channels, it was suggested that PSs with unusual microstructures might be produced via constrained polymerization of styrene monomer in its gamma-CD-IC crystals. The in situ polymerization of styrene inside the narrow channels of its gamma-CD-IC crystals suspended in aqueous media was Performed. Alternatively, the solid-state polymerization of styrene/gamma-CD-IC has also been conducted by exposure to gamma-radiation. It was found that most host gamma-CD molecules slip off during polymerization and the channel structure was not preserved. Consequently, much of the guest styrene monomer polymerizes outside of the host gamma-CD channels, where the constrained environment is absent. Yet, a lightly rotaxanated structure has been obtained, where some threaded gamma-CD molecules similar to 15 wt% (similar to 1 gamma-CD per 70 PS repeat units) are permanently entrapped along the PS chains after polymerization. C-13 NMR spectra of PSs synthesized from styrene/gamma-CD-IC and homogeneously in toluene show some differences, which are presumably due to variations in the stereosequences of PSs obtained from the partially constrained polymerization of styrene/gamma-CD-IC. (c) 2006 Elsevier Ltd. All rights reserved.