Mouse Chromosome 11

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46996/1/335_2004_Article_BF00648429.pd

Computer simulation of dendrimers and hyperbranched polymers

Highly branched molecules such as dendrimers possess fully branched, focal-cored tree-like structures whereas their hyperbranched cousins contain a mixture of branched and unbranched sites and hence typically do not have a symmetric topology. Experiment and simulation have revealed these materials can exhibit an intrinsic shear viscosity that peaks with molecular weight rather than one that constantly increases with molecular weight as illustrated by linear chains. Applications in supramolecular chemistry, drug delivery and other guest-host applications bave motivated further interest in these molecules in terrns of their size, shape and interior density profiles. This talk will summarise an ongoing computational investigation into dendrimers and hyperbranched polymers under shear and elongational flow. The technique employed is Brownian dynamics in the presence of excluded volume and hydrodynamic interactions. The behaviour of various statistical and rheological quantities will be presented including their dependence on the extent and the distribution of branched sites within the dendritic molecule

Location of terminal groups of dendrimers: brownian dynamics simulation

Note : No abstrac

Computer Simulations of Hyperbranched Polymers: the Influence of the Wiener Index on the Intrinsic Viscosity and Radius of Gyration

The influence of the Wiener index on solution properties of trifunctional hyperbranched polymers has been investigated using Brownian dynamics simulations with excluded volume and hydrodynamic interactions. A range of degrees of polymerization (N) and degrees of branching (DB) were used. For each DB and N, several molecules with different Wiener indices (W) were simulated, where W depends on the arrangement of branch points. The intrinsic viscosity and the radius of gyration (Rg) of HPs were both observed to scale with W at a constant N via a power law relationship, as found in the literature. Through their relationships to W, an expression relating intrinsic viscosity to Rg was obtained. This relationship is found to fall centrally between the predictions of Flory and Fox for linear polymers and that of Zimm and Kilb for branched polymers. Molecular shape in solution is also found to depend on W and N, as observed through the W dependence of the ratio of Rg to the hydrodynamic radius, Rh