Properties of star-branched (co)polymers

Computer simulation methods offer highly efficient routes for the investigation of the properties of polymeric materials as well as for the investigation of kinetic aspects of the proceeding polymerisation process: Global chain properties like size, shape, orientation and morphology can be studied on a molecular scale as well as specific interactions between distinct positions within the polymer chains, i.e. between atoms, monomer-units or segments (consisting of several monomers) depending on the actual model used. Dissipative Particle Dynamics (DPD) is a relatively new but most promising technique for the simulation of mesoscopic properties of a wide variety of systems including homopolymers and copolymers. Simulation parameters may be connected to Flory Huggins parameters and thus in turn to specific experimental conditions allowing for a comparison of experimental and numeric results. The aim of the project is a detailed investigation (mainly by use of DPD) of star branched polymers consisting of homopolymers and of different homopolymers (miktoarm stars) or copolymers, respectively. Characteristic properties should be investigated as a function of concentration and solvent quality in the entire range of regimes: The upper limit of a solvent free system is characteristic of a polymer melt or of an amorphous phase (according to the actual temperature) and thus simply represents polymer materials. The lower limit corresponds to an infinitely diluted solution of a polymeric chain or star. Detailed knowledge of the influence of branching and composition on the behavior of polymers on a molecular scale should give a route for the design of materials with tailor-made properties in solution and/or bulk. Furthermore, the investigation of shielding effects on (reactive) sites located at specific position within chains and stars should give a clear picture about what is going on during the so-called RAFT (reversible addition fragmentation chain transfer) polymerization process, which is a rather new technique for the preparation of well defined star branched polymers.

Computer simulation methods offer highly efficient routes for the investigation of the properties of polymeric materials as well as for the investigation of kinetic aspects of the proceeding polymerisation process: Global chain properties like size, shape, orientation and morphology can be studied on a molecular scale as well as specific interactions between distinct positions within the polymer chains, i.e. between atoms, monomer-units or segments (consisting of several monomers) depending on the actual model used. Dissipative Particle Dynamics (DPD) is a relatively new but most promising technique for the simulation of mesoscopic properties of a wide variety of systems including homopolymers and copolymers. Simulation parameters may be connected to Flory Huggins parameters and thus in turn to specific experimental conditions allowing for a comparison of experimental and numeric results. The aim of the project is a detailed investigation (mainly by use of DPD) of star branched polymers consisting of homopolymers and of different homopolymers (miktoarm stars) or copolymers, respectively. Characteristic properties should be investigated as a function of concentration and solvent quality in the entire range of regimes: The upper limit of a solvent free system is characteristic of a polymer melt or of an amorphous phase (according to the actual temperature) and thus simply represents polymer materials. The lower limit corresponds to an infinitely diluted solution of a polymeric chain or star. Detailed knowledge of the influence of branching and composition on the behavior of polymers on a molecular scale should give a route for the design of materials with tailor-made properties in solution and/or bulk. Furthermore, the investigation of shielding effects on (reactive) sites located at specific position within chains and stars should give a clear picture about what is going on during the so-called RAFT (reversible addition fragmentation chain transfer) polymerization process, which is a rather new technique for the preparation of well defined star branched polymers.