Imaging individual chains and aggregates on conjugated polymer films
2003 (English)In: ORGANIC AND POLYMERIC MATERIALS AND DEVICES, MATERIALS RESEARCH SOCIETY , 2003, Vol. 771, 23-28 p.Conference paper (Refereed)
We demonstrate a novel method to visualize individual molecular chains in the surface layer of organic semiconducting polymer films of arbitrary thickness. The method is based on scanning force microscopy and employs a combination of a sensitive phase detection system and metal coated tips with a low (similar to1 N/m) spring constant and a relatively high Q factor (similar to200). The molecularly resolved morphology is observed in phase images that are taken simultaneously with the topography. Surprisingly, we found that, when the tip apex radius exceeds the intermolecular spacing in the surface layer, surface aggregates -when present- are visualized. In both cases, the phase contrast is shown to result from van der Waals interaction between the conjugated backbone of the polymer chains and the metallic tip, and can quantitatively be described by a simple harmonic oscillator model. We have employed this method to study the morphology of poly(p-phenylene vinylene) (PPV) derivatives with different substitutions.
Place, publisher, year, edition, pages
MATERIALS RESEARCH SOCIETY , 2003. Vol. 771, 23-28 p.
, MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS, ISSN 0272-9172 ; 771
IdentifiersURN: urn:nbn:se:liu:diva-118218ISI: 000185782000004ISBN: 1-55899-708-3OAI: oai:DiVA.org:liu-118218DiVA: diva2:813329
Symposium on Organic and Polymeric Materials and Devices held at the 2003 MRS Spring Meeting