0000000000335851
AUTHOR
Do Y. Yoon
Synthesis and characterization of novel organic–inorganic hybrid block copolymers
Novel organic–inorganic hybrid block copolymers based on poly(methylsilsesquioxanes) (PMSSQs) have been synthesized. Two routes to functionalized PMSSQs are presented and from both atom transfer radical polymerization of methylmethacrylate could be performed. Copolymers with different block ratios have been polymerized and were characterized. In particular, thermal properties were investigated by TGA and the promising thermal decomposition behaviour makes the copolymers potential candidates as pore generators in future nanoporous materials. Additionally, these copolymers were analysed as surface coatings of regular PMMA. Contact angle measurements proved the dramatic effect on the surface p…
Chain Motion in an Unentangled Polyethylene Melt: A Critical Test of the Rouse Model by Molecular Dynamics Simulations and Neutron Spin Echo Spectroscopy
We have investigated the dynamic structure factor for single-chain relaxation in a polyethylene melt by means of molecular dynamics simulations and neutron spin echo spectroscopy. After accounting for a 20% difference in the chain self-diffusion coefficient between simulation and experiment we find a perfect quantitative agreement of the intermediate dynamic structure factor over the whole range of momentum transfer studied. Based on this quantitative agreement one can test the experimental results for deviations from standard Rouse behavior reported so far for only computer simulations of polymer melt dynamics.
Correlations between Ion Conductivity and Polymer Dynamics in Hyperbranched Poly(ethylene oxide) Electrolytes for Lithium-Ion Batteries
Poly(ethylene oxide)s with varying degrees of hyperbranching are effective at preventing the crystallization of PEO and lead to approximately a 100-fold increase in the Li-ion conductivity below 50 °C as compared with linear PEO. The Li-ion conductivities, which increase further upon permethylation of the hydroxyl termini, are found to correlate quantitatively with the fast segmental dynamics of PEO as measured by inelastic neutron scattering.
Static and Dynamic Properties of a n-C100H202 Melt from Molecular Dynamics Simulations
We present in this work results from atomistic molecular dynamics simulations of a n-C100H202 melt. This work represents a first effort to simulate a fully equilibrated ensemble of chains of suffic...
Temperature dependence of surface reorganization characteristics of amphiphilic block copolymer in air and in water studied by scanning force microscopy
We have investigated the surface reorganization characteristics of a novel amphiphilic diblock copolymer, poly(acetic acid-2-(2-(4-vinyl-phenoxy)-ethoxy)-ethylester)-block-polystyrene (PAEES-b-PS), in response to varying interfaces from air to water and vice-versa at various temperatures. The surface reorganization characteristics of the block copolymer films was monitored by scanning force microscopy, in order to delineate the kinetically controlled morphological process of surface reorganization of a diblock copolymer, with a particular emphasis on the phase contrast signal which allowed the determination of local composition patterns of PAEES-b-PS at the surface. Upon heating a water-an…