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Updated: Jun 25, 2026
06:55
Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
Length and time-dependent rates in diffusion-controlled reactions with conjugated polymers.
Paiboon Sreearunothai1, Sadayuki Asaoka, Andrew R Cook
1Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000, USA.
The Journal of Physical Chemistry. A
|March 6, 2009
Summary
The reaction rate of solvated electrons with conjugated fluorene polymers increases with length, but less than expected. Large transient effects, unprecedented in size, were observed for longer polymer chains.
Area of Science:
- Physical Chemistry
- Polymer Science
- Photochemistry
Background:
- Solvated electrons are highly reactive species.
- Conjugated polymers exhibit unique electronic properties.
Purpose of the Study:
- To measure the rate constants of diffusion-controlled reactions.
- To investigate the effect of chain length on reaction rates.
- To compare experimental results with theoretical models.
Main Methods:
- Reactions of solvated electrons with fluorene oligomers and polymers in THF.
- Separation of polyfluorenes by preparative gel permeation chromatography (GPC).
- Determination of attachment rate constants (k(inf)) as a function of length.
Main Results:
- Rate constants increased by a factor of 16 for a 133-fold increase in polymer length.
- Experimental data align well with theoretical models for diffusion to elongated objects.
- Observed large transient effects in rate constants for longer polymer molecules, exceeding predictions.
Conclusions:
- The length dependence of reaction rates is less than linear.
- Transient effects become dominant for longer polymer chains.
- Quantitative confirmation of unprecedented transient effects provides new insights into diffusion-controlled reactions.
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