Understanding the hydrolysis, condensation and solvent evaporation processes in precursor sols for electrospun Ultrafine fibers permits good control over fiber diameter and morphology in a reproducible manner. The (CH(3)CH(2)CH(2)O)(4)Ti/AcOH/Poly(n-Vinyl Pyrrolidone)/Ethanol sol-gel system is used to illustrate this principle. Four different co-solvents (ether, DMF, DMSO and formamide) were also used to establish their impact on fiber diameter. Among other physical properties of solvents, the relative volatility of the solvent mixtures used in this Study was found to influence the morphology of the electrospun fibers by affecting the stability and range of existence of the electrified jet. (C) 2008 Elsevier B.V. All rights reserved.