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Christopher Copplestone


Current Position: M.D. Student, Oxford University
Undergraduate Institution: Oxford University

M. Eng. Thesis Research:

A block copolymer made from immiscible blocks cannot phase separate on a macroscopic level due to the blocks being covalently bonded.  Instead microsegregation will occur and a morphology will form depending on the relative lengths of each block.  The periodic morphologies that can be formed are on a nanoscale and are attractive for use in lithography.  A morphology with cylinders that are aligned perpendicularly to the substrate is particularly desirable for this purpose.  For this to occur the favourable wetting of one of the blocks has to be overcome.  Aligning with an electric field or using a random copolymer layer above the substrate has been used to achieved this.  However to cut the number of process steps it is desirable to have a molecular architecture which self assembles this structure and this is currently being investigated.  A perpendicular alignment is seen at the boundary of layers of parallel-aligned cylinders, for example an island.  What causes this to occur is also being studied.  Tapping-mode AFM is the primary tool being used to examine the block copolymer film morphologies.