For the first time, high-percentage molybdosilicic acid fiber mats (20 - 80% H4SiMo12O40) were prepared using the electrospinning technique. The fiber mats were characterized by IR, XRD, and DSC. The results indicated that poly(vinyl alcohol) was changed from a semicrystalline to an amorphous state with an increasing molybdosilicic acid content. The results from scanning electron microscopy (SEM) showed that the average diameter of the fibers was about 285-600 nm. The effects of the viscosity and conductivity of the H4SiMo12O40/poly(vinyl alcohol) solution on the morphologies of the fiber mats were investigated. The swelling properties of the fiber mats in water were also studied. (C) 2003 Wiley Periodicals, Inc.