Abstract: TLChas been used in distinguishing and characterizing polystyrene homopolymer and polystyrene-polydimethylsiloxane diblock or triblock copolymers. When developed with chloform or other suitable developing agents the polymers mentioned above would give different R_f values. This method is independent of the molecular weights and compositions of the samples. It may be used to determine rapidly whether the anionic polymerization reaction is successful.