Preparation and structural characterization of sodium polyphosphate coacervate as a precursor for optical materials

Abstract

This paper describes the preparation of Sodium Polyphosphates Coacervates (NaPC) through the direct addition of different methanol molar fractions to a sodium polyphosphate solution. The presence of methanol reduces the dielectric constant medium and it promotes the coacervate formation. Rheology measurement shows that the NaPC viscosity is dependent on a methanol molar fraction, which is caused by the dielectric constant reduction of the water-methanol mixture. Raman spectra for the lyophilized NaPC show that the symmetric P-Ot stretching mode is more sensitive than the symmetric P-Ob stretching mode, due to the approach of the adjacent polyphosphate chains. The 31P NMR spectra also confirm a decrease in the Q2/Q1 ratio because of the methanol content. Besides, we have obtained transparent soft Glass-Materials to melt NaPC at 800 °C.