PMSE 26 |
| It is an inherent property of block copolymer microphase structures that large scale, defect free structures are difficult to achieve. Different kinds of external fields have been used to achieve samples with uniform orientation. Comparing electric and magnetic fields, it turns out that the effects of the former are usually stronger and more easy to use. A case of special interest are thin films in which orientation by interfacial interactions are in competition with electric field induced alignment. We will present a detailed analysis of the microdomain structure in block copolymers films of different thicknesses and the effect an electric field has on these structures. Surface induced orientation is lost for thicker films, but it can be recovered if reorganization of the microphase structure takes place under a unidirectional compressive load. Unless interfacial interactions are very weak the electric field is unable to overcome the interfacial interactions completely. |
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Block Copolymers as Nanoscale Materials
8:00 AM-11:45 AM, Sunday, 10 September 2006 San Francisco Marriott -- Salon 7, Oral
Division of Polymeric Materials: Science & Engineering |