I have come across two papers, just check if they have useful information for your desired preparation of nano poly vinyl alcohol.
J Control Release. 1998 Dec 4;56(1-3):117-26.
Poly(vinyl alcohol) nanoparticles prepared by freezing-thawing process for protein/peptide drug delivery.
Authors: Li JK1, Wang N, Wu XS.
Journal of Drug Delivery
Volume 2011 (2011), Article ID 962743, 8 pages
http://dx.doi.org/10.1155/2011/962743
Research Article
Preparation of a Nanoscaled Poly(vinyl alcohol)/Hydroxyapatite/DNA Complex Using High Hydrostatic Pressure Technology for In Vitro and In Vivo Gene Delivery
Èlectrospraying will produce monodisperse nano or micro particles. There are many papers available in this area. Feel free to contact me if you require more information on the technique.