Direct Measurement of the End‐to‐End Distance of Individual Polyfluorene Polymer Chains

Abstract

Wide‐field imaging of individual multichromophoric molecules and successive photobleaching were used to determine, accurately, the relative position of the chromophores in such systems. First, a polyphenylene dendrimer with well‐defined geometry was used to establish the accuracy in localization that can be obtained by this methodology. For a signal‐to‐noise ratio of 20, interchromophoric distances could be measured with 4 nm accuracy. Next, the method was used to determine the end‐to‐end distribution of an end‐capped polyfluorene polymer. From comparison between the experimental and simulated distributions, information on the conformation of the polymer could be deduced. It was found that the polymer has a nonlinear conformation. A conjugation length of six monomer units gave the best fit of the experimental data to the proposed model.