返回Google圖書搜尋

Intermolecular Bonding in Conjugated Polymers

出版	University of California, Santa Barbara, 2005
ISBN	05422808179780542280818
URL	http://books.google.com.hk/books?id=kHOAAQAACAAJ&hl=&source=gbs_api

註釋Conjugated polymers are an unique class of molecules that combine the electronic properties of semiconductors with the mechanical properties of plastics. Recently, it has been proposed that conjugated polymers could be used as the basis for high sensitivity biosensors. This suggestion has sparked interest in the solution properties of these molecules. In this work we examine the role of the valence electrons as the driving force in the formation of conjugated polymer aggregates. We find that when the polymers approach each other to within a few angstroms the pi orbital overlap leads to the formation of covalent-like bonds of energy & sim;kBT . These bonds form even when the Fermi level lies within a gap in the energy spectrum and, therefore, the anti-bonding states are occupied. In general, the electrons will favor conformations in which the polymers are parallel so that many such bonds can form. However, the conformational entropy of the polymers as well as electrostatic repulsion favor the unbound state. The competition between these forces determines whether the polymers are unbound, loosely aggregated, or tightly bundled.