Complexation In Weakly Attractive Copolymers With Varying Composition And Topology: Linking Fluorescence Experiments And Molecular Monte Carlo Simulations

The intramolecular complex formation occurring in miktoarm star polymers and block copolymers is investigated experimentally and by means of Monte Carlo simulations. The driving force of the complex formation is an attractive interaction between the different blocks. In the simulations, a simple bead-spring model with an attractive Lennard-Jones potential is used to mimic the complexation. The effect of topology (arm number) and composition (arm length) is simulated. Experimentally, star-shaped polymeric systems and diblock copolymers of poly(propylene oxide) (PPO) and poly(dimethylaminoethyl methacrylate) (PDMAEMA) of varying degrees of polymerization are investigated. By quantifying the complex formation with help of fluorescence spectroscopy of a polarity-sensitive probe, we show that a complex is formed preferably at high degrees of polymerization of PDMAEMA and a high number of PDMAEMA arms. These results are in accordance with the simulations: we show that the actual amount of PPO in the complex correlates with the fluorescence dye uptake.