Determination of the Ordered Structure in Conjugated-Coil Diblock Copolymers Films from a Thickness Gradient Prepared by Spin-Coated Drop Technique
| Autor: | Mahmoud Al-Hussein, Rainer Gehrke, U. Vainio, Volker Körstgens, Ezzeldin Metwalli, Peter Müller-Buschbaum, Ronald Gebhardt, Stephan V. Roth, Matthias A. Ruderer, M. Burghammer, Ralph Döhrmann |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | Macromolecules. 42:4230-4236 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma900382t |
| Popis: | Investigating the thickness dependence of ordered structure of thin films of electrically conducting conjugated polymers with nano-ordered morphologies is essential for optimizing their applications in advanced electrooptic devices. We demonstrate here that by spin-coating a small drop of a conjugated-coil diblock copolymer, a thickness gradient varying between tens of nanometers to a few micrometers is formed at the drop rim. Compared to other widely used solution casting methods for the preparation of thickness gradients, the spin-coated drop technique produces film gradients with thickness in the interesting range for most applications in an extremely short preparation time. Using a submicrometer-sized X-ray beam and a scanning technique, spatial mappings of the gradient area are obtained with submicrometer grazing incidence small-angle X-ray scattering (sub-μGISAXS) for the first time. Investigating the thickness gradient with sub-μGISAXS has the advantage of saving the preparations and investigations of many samples each with a certain thickness under identical conditions. As a model system, we use the diblock copolymer polystyrene-block-poly(p-phenylene) with a thickness gradient ranging between 80 and 2280 nm. Detailed analysis of the scattering patterns at selected positions along the gradient identifies a regime of lateral order within a thickness range of 80―210 nm. |
| Databáze: | OpenAIRE |
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