This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record. ; Three-dimensional polymer nanofibrous mats with tunable wettability have been fabricated using a single step non-conductive template assisted electrospinning process. Cellulose acetate nanofibers are electrospun over a nylon mesh, which acts as thetemplate. The as-deposited fiber mat is removed from this template to produce a free standing three-dimensional micropatterned nanofi-brous mat. By simply varying the template mesh dimensions, the fraction of the air-liquid interface can be changed which allows controlof the wetting mechanics. It is shown that the water contact angle can be varied from about 308 for a planar network to about 1408 for apatterned mat implying a complete transition from hydrophilic to hydrophobic behavior. Furthermore, upon stretching the fiber matloses its pattern irreversibly and reducing the contact angle from 1408 to 1108 with increasing stretching. ; Support of a DST-UKIERI grant is gratefully acknowl-edged. M.K. and C.S.S. acknowledge the Indian Institute of Tech-nology Hyderabad, for providing necessary research infrastructureto carry out this wor