Chien-Hua Tu

University of Pennsylvania | UP · Department of Materials Science and Engineering

Semicrystalline polymers are solids that are supposed to flow only above their melting temperature. By using confinement within nanoscopic cylindrical pores, we show that a semicrystalline polymer can flow at temperatures below the melting point with a viscosity intermediate to the melt and crystal states. During this process, the capillary force i...

Monitoring of nucleus geometry and growth into dual types of periodically ring-banded morphology in poly(nonamethylene terephthalate) (PNT), respectively, Type-1 and Type-2, are done with detailed analyses using polarized-light optical microscopy (POM) in-situ CCD recording; the periodic assembly morphologies are characterized using atomic-force mi...

It is often assumed that carbon nanotubes (CNTs) stimulate neuronal differentiation by transferring electrical signals and enhancing neuronal excitability. Given this, CNT–hydrogel composites are regarded as potential materials able to combine high electrical conductivity with biocompatibility, and therefore promote nerve regeneration. However, whe...

Crystallized poly(nonamethylene terephthalate) (PNT) displays mirror-image and Fermat’s-spiral ring-banded spherulites, respectively. Interior anatomy by SEM and AFM microscopic analyses show that the lamellar arrangement of grating-board structures inside the 3D bulk banded PNT is correlated to top-surface topography of alternate ridge and valley...

Using in situ nanodielectric spectroscopy we demonstrate that the imbibition kinetics of cis-1,4-polyisoprene in native alumina nanopores proceeds in two time regimes both with higher effective viscosity than bulk. This finding is discussed by a microscopic picture that considers the competition from an increasing number of chains entering the pore...

Thorough microscopy analyses are done on dissecting 3D interiors of poly(nonamethylene terephthalate) (PNT) banded spherulites. Growth of a specific type (Type-I) of banded spherulites is initiated from highly elongated sheaf-like nuclei, with asymmetrically grown lamellae packed as a multi-shell structure, leading to resemblance of a dual-face sph...