Molecular rearrangements observed by single-molecule microscopy

We have applied quantitative single-molecule photoluminescence microscopy f or directly observing molecular rearrangements in a polymeric material subj ected to tensile deformation. The system examined is a blend of fluorescent conjugated polymer molecules embedded in polyethylene, known to exhibit st rong phase separation. Statistical analysis of the sizes of phase-separated domains reveals that during tensile deformation large domains of fluoresce nt molecules are transformed into smaller clusters and ultimately isolated single molecules. In addition to elucidating the nature of the stretch-indu ced morphology change, our work underscores the fundamental value of single -molecule techniques for material analysis [1]. (C) 2001 Elsevier Science B .V. All rights reserved.