Novel biodegradable multiblock copolymers of [PCL-b-P(THF-co-CL)](m) with PCL fractions of 53.3 and 88.4 wt % were prepared by Janus polymerization of epsilon-caprolactone (CL) and tetrahydrofuran (THF). Their electrospun mats were obtained with optimized parameters containing bead-free nanofibers whose diameters were between 290 and 520 nm. The mechanical properties of the nanofiber scaffolds were measured showing the tensile strength and strain at break of 8-10 MPa and 123-161%, respectively. Annealing improved their mechanical properties and their tensile strength and strain at break of the samples increased to 10-13 MPa and 267-338%, respectively. Due to the porous structure and crystallization in nanoscale confinement, the mechanical properties of the nanofiber scaffolds appeared as plastics, rather than as the elastomers observed in bulk thermal-molded film.