Effect of surface silanol density of silica nanoparticles on the adsorption isotherms and enthalpy of adsorbed poly(ethylene ) oxide

POLY 91

Rajesh Madathingal, rajesh@temple.edu and Stephanie Wunder, slwunder@temple.edu. Department of Chemistry, Temple University, 13th and Norris Streets, 1901 N. 13th Street, Philadelphia, PA 19122
Poly(ethylene oxide),(PEO) was adsorbed on to three different types of silica (fumed, Stober and colloidal). The silanol group density was varied by heat treatment at 600°C & 1000°C, or the surface was made hydrophobic by treatment with hexamethyldisilazane. The composites were characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Plateau PEO adsorption isotherms, determined by TGA, increased with increasing silanol density and were least for hydrophobic silica. The melt enthalpy determined by DSC increased with decreased silanol density and for fixed silanol density the melt enthalpy increased as the adsorbed amount of PEO increased.
 

General Papers
2:00 PM-4:20 PM, Sunday, April 6, 2008 Hilton New Orleans Riverside -- Grand Salon 4, Oral

Division of Polymer Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008