Single Molecule Wobbling in Cylindrical Mesopores
Pramanik, R; Ito, T; Higgins, DA
| HERO ID | 3575839 |
|---|---|
| In Press | No |
| Year | 2013 |
| Title | Single Molecule Wobbling in Cylindrical Mesopores |
| Authors | Pramanik, R; Ito, T; Higgins, DA |
| Journal | Journal of Physical Chemistry C |
| Volume | 117 |
| Issue | 7 |
| Page Numbers | 3668-3673 |
| Abstract | Simultaneous single molecule tracking (SMT) and single molecule emission dichroism (SMED) measurements are used to investigate the translational and orientational motions of fluorescent probes diffusing within mesoporous silica films. The results afford a quantitative measure of molecular confinement within the mesopores and allow for the accessible pore diameter to be determined with higher precision than can be achieved by common SMT methods alone. In these studies, dual-polarization wide-field video microscopy is used to obtain SMT data simultaneously in two orthogonal polarizations. A rod-shaped perylene diimide dye (C11OPDI) is employed as the probe and is excited by circularly polarized light. SMT reveals a predominance of one-dimensional dye diffusion within the mesopores. The SMED data demonstrate that the molecules diffuse in an oriented state, with their long axes parallel, on average, to the long axis of the mesopores. Theoretical expressions quantitatively relating the SMED and SMT results to the extent of C11OPDI orientational wobbling are developed. The results are consistent with confined wobbling of the single molecules within the mesopores. An ensemble-averaged wobbling angle of 19 3 is obtained, yielding an estimated accessible pore diameter of 1.3 +/- 0.2 nm. |
| Doi | 10.1021/jp400479w |
| Wosid | WOS:000315432100055 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |