Fig. 3.

Shape dependence of single P3HT chains on matrix material at room temperature. (A) The modulation of PL intensity under rotation of the plane of polarization of the exciting laser is recorded. The modulation depth M provides a measure of chain extension and order: chains that mix well with the matrix (i.e., are well solvated) form random-coil structures that absorb any polarization of light. Poorly solvated chains, however, collapse, leading to ordered anisotropic rod-like structures. (B) Histogram of M values for single chains in Zeonex and PMMA. In Zeonex, isotropic structures are formed, whereas PMMA gives rise to highly anisotropic arrangements of the chains.