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RESEARCH PRODUCT

One is Enough: Influencing Polymer Properties with a Single Chromophoric Unit

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1) Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, D-­‐20146 Hamburg, Germany 2) WCU program of C2E2, School of Chemical and Biological, Engineering, College of Engineering, Seoul National University, Seoul, Korea Designing a polymer usually involves the incorporation of multiple functional units into a polymer chain, which mutually determine the polymer properties. By combining various functional units, a myriad of polymer properties can be fine-­‐ tuned. Classical polymer chemistry teaches us that a single functional group -­‐-­‐ in particular the end-­‐group of a polymer chain -­‐-­‐ does not contribute to the polymer properties, as is indeed true in most cases. However, nature tells us a different story. The photoisomerization of a single retinal molecule inside a large polymeric complex called rhodopsin is the mechanism for the highly sensitive ocular system found in vertebrate photoreceptors. Recently, the idea of stimulating a single chromophore on a polymer chain and amplifying its effect through the polymer chain has motivated the evolution of new exciting research areas in polymer science. To attain such high synthetic precision, it is crucial to choose not only an appropriate chromophoric unit that shows reversible or irreversible changes, but also synthetic routes that enable the attachment of a single dye to one polymer chain. Different synthetic examples will be discussed.