The monomolecular particle agglomerates of polystyrenes were obtained by freeze-drying of its very dilutesolutions of 1.3×10-5-2.0×10-5 g/mL in benzene: cylcohexane (100:1) solvents

and they were annealed at roomtemperature for hundred days before use. According to13C-NMR measurement the polystyrenes should be practically atactic.The number average molecular weights of the samples are 2.80×103

2.00×104

and 1.55×106

respectively. The freeze-dried aPS with a molecular weight higher than 104 show two new IR absorption bands at 1098 and 1261 cm-1

which are absent in the normal αPS and freeze-dried styrene oligomer.It was also found that the low molecular weight samples can only form powders

whereas the freeze-dried αPS with higher molecular weight form a mixture of powders and fibrils

of which the longer fibrils show a much stronger 1261 cm-1 band than the shorter fibrils and the powder.It seems that the 1261 cm-1 band corresponds to the stacking behavior of monomolecular particles.