In this study

the effects of the various control parameters in preparing high quality PS-b-PLLA single crystals as well as PS-b-PLLA/PLLA composite single crystals and their thermodynamic properties in solutions and in the bulk state are reported.Main control parameters including the seeding temperature (Ts) and time (ts)

crystallization temperature (Tc) are discussed based on their effects on the size and its distribution

shape and thickness of the resulting crystals.In general

increasing Ts and ts lead to larger crystals with narrower distributions.Increasing Tc leads to a morphology transition from lozenge to truncated lozenge.DSC thermal analysis show that while the single crystals in solution have one melting point

the DSC profiles show a significant melting and recrystallization behavior in the bulk state after removing the solvent

which suggests that the crystals are under a metastable state in the bulk.Interestingly

when crystals are annealed at different temperatures below the onset melting point

the DSC heating profiles show similar initial melting point and the recrystallization process

indicating that the thermodynamic stability of the crystals does not change upon annealing.These results further suggest that the lamellar thickening via -relaxation in the PLLA lamellar crystals is prohibited and the high thermodynamic stability of crystals can be achieved only by recrystallization.