Coarse-Grained MD Simulations of Selfassembly of Poly(Butadiene-B-Ethylene Oxide) (PB-PEO) in Water and Shear Flow Dynamics of Pb-Peo Vesicle(s)

• Main Author: Chaudhary, Meenakshi
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2017
• Subjects: Chemical engineering; Computational chemistry
• ISBN: 9780355648317; 0355648318

Amphiphilic surfactants have attracted huge attention in the last two decades owing to their ability to form a variety of aggregates in solution, such as spherical micelles, lamellae or bilayers, worm-like or cylindrical micelles. Block copolymers are a special class of surfactants consisting of two or more different monomer units, which aggregate in dilute solutions and exhibit different morphologies. Importantly, diblock copolymers with a hydrophilic/hydrophobic ratio similar to that of a lipid membrane can form vesicles which have shown to display remarkable structural and dynamic properties different from those of liposomes. The behavior of polymer vesicles under shear flow reveals several non-equilibrium dynamics such as trembling, tumbling or tank-treading. Molecular Dynamics (MD) simulations have become a preferred method for gaining a predictive insight into the topology and characterization of diblock copolymer aggregates in solution. The aggregation behavior of diblock Poly(Butadiene-EthyleneOxide) (PB-PEO) copolymers in water is elucidated here through MD simulations using MARTINI coarse-grain model for polymers. A comparative analysis of simulation results with experimental observations has been made and a phase diagram defining regions of morphological transformation has been contructed. An attempt has been made to understand spatiotemporal instabilities in PB-PEO vesicles under shear flow as a function of orientation angle, shape and position of the vesicle relative to the shear plane.