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Self Assembly of Block Copolymers. Name: Donal O’Donoghue, National University of Ireland, Cork. Research Group: Prof. Glenn Fredrickson’s group in the Complex Fluid Design Consortium Supervisor: Dr. Nathaniel Lynd Project Overview:
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Self Assembly of Block Copolymers Name: Donal O’Donoghue, National University of Ireland, Cork. Research Group: Prof. Glenn Fredrickson’s group in the Complex Fluid Design Consortium Supervisor: Dr. Nathaniel Lynd Project Overview: Numerically investigating the nano scale architectures of different block copolymer melts formed by microphase separation, using self consistent field theory (SCFT).
Why is this research of interest to us? • Thermoplastic elastomers (TPE), materials which can be stretched and heated up and yet return to their original shape, can be made with block copolymers. • TPE’s are utilised in many different products, such as shoe soles, gaskets, tires, etc. Hence this research is of interest to many different industries. • Block copolymers are of interest from a purely scientific point of view since they “microphase separate” to form periodic nanostructures of various different architectures.
Microphase Separation of Diblock Copolymers • Diblock copolymers will self-assemble into different structures depending on their composition. • Parameters which are important are the interaction strength between different monomer species A and B, N, and the fractional composition of the monomer species A, fA .
Using Self Consistent Mean Field Theory To Numerically Investigate Diblock Copolymers • Polymers are modelled as smooth space curves, which follow Gaussian chain statistics • Polymers deform with a spring-like stretching energy (like microscopic elastic threads) • Interaction between A/B segments treated as simple contact forces • Our particle based theory is then changed to a field theory using a mathematical transformation. • Contact forces are replaced by an interaction field • Incompressibility condition replaced by a Lagrange field • Polymer concentrations as a function of space are calculated from a set of self consistent equations.