Glass transition of nano-sized single chain globules

Nano-sized polymer globules were prepared by atomization spraying and drying of a dilute polymer solution. Transmission electron microscope measurements indicated that the particle of the globules matched with that of polymer single chains. Thermal analysis showed that the nano-sized particles exhibit a significantly higher glass transition temperature (T-g) than does the corresponding bulk polymer. This discovery cannot be explained by kinetic theories. Entropy analysis does indicate that polymer chains in the globular state should have a higher T-g. (C) 2002 Elsevier Science Ltd. All rights reserved.