The pH-induced conformational transition of poly(l,3-propylene phosphate) (PPP) in an aqueous solution has been investigated by the potentiometric method. It has been found that PPP undergoes a cooperative macroconformational transition upon changing the fraction of dissociated phosphate groups from
Conformation and transport properties of poly(alkylene phosphate)—A synthetic analogue of natural teichoic acids—II. Conductivity percolation in poly(vinyl chloride)-poly(1,3-propylene phosphate) membranes
✍ Scribed by Romuald Wódzki
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- English
- Weight
- 347 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0014-3057
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✦ Synopsis
The electrical conductivity of poly(vinyl chloride)-poly(1,3-propylene phosphate) membranes was measured as a function of ionic polymer content and its ionic state. The results are discussed by applying the percolation conductivity theory and considering the conformational transition upon neutralization of PPP. It was found that the critical volume fraction of PPP in membranes of 0.06 did not depend on an ionic form of polymer. A critical exponent (t) predicted by the percolation theory was found to be 1.64 for the membrane in its sodium form and 1.04 in its hydrogen form. The value t = 1.04 is below the theoretical value of t, i.e. 1.6 + 0.2, for conductor/insulator systems. This effect may result from the reduced conductivity of PPP after the transition from extended coil to the bypercoiled state in the ionic polymer.
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