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Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Donor-acceptor-promoted gelation of polyaromatic compounds
Dan Rizkov1, Jenny Gun, Ovadia Lev
1The Institute of Chemistry, The Hebrew University of Jerusalem, Edmond E. Safra Givat Ram Campus, Jerusalem, 91904 Israel.
Langmuir : the ACS Journal of Surfaces and Colloids
|December 14, 2005
Summary
Electron acceptors like dinitrobenzoates can form two-component organogels with polyaromatic hydrocarbons (PAHs). This process, driven by donor-acceptor pairs, allows significant PAH assembly without covalent bonds.
Area of Science:
- Supramolecular Chemistry
- Materials Science
Background:
- Low molecular mass organogels are formed by small molecules that reversibly gelify solvents.
- Traditional organogel formation often involves specific molecular structures or covalent interactions.
Purpose of the Study:
- To demonstrate the formation of two-component donor-acceptor organogels using electron acceptors and polyaromatic hydrocarbons (PAHs).
- To investigate the role of donor-acceptor pairs in the self-assembly and gelation process.
Main Methods:
- Utilized dinitrobenzoates as model electron acceptors.
- Employed spectrophotometry, fluorescence, and time-resolved fluorescence spectroscopy.
- Conducted temperature-dependent 1H NMR studies to analyze gel thermodynamics and species concentrations.
Main Results:
- Electron acceptors facilitated the gelation of significantly larger amounts (15-16 fold) of PAHs.
- Established the formation of two-component organogels in various solvents.
- Identified donor-acceptor pairs as the core structural element responsible for long-range order.
Conclusions:
- Donor-acceptor interactions are crucial for creating novel organogels from components not inherently capable of gelation.
- 1H NMR provides a direct method for quantifying species and determining the thermodynamic parameters (enthalpy, entropy, free energy) of gel formation.
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