Recently developed two-dimensional multilayer coextrusion and post-process drawing were combined to fabricate polyolefin composites with independently tunable size (9 mu m width x 3 mu m thickness to 5 mu m width x 0.9 mu m thickness) and mechanics (e.g. modulus from 1340 to 2010 MPa). Post-process drawing of the composite studied via in situ synchrotron WAXS and SAXS imparted higher crystallinity and more uniform and aligned crystallites (f(H, PP) = 0.93 and f(H,HDPE) = 0.90) resulting in an improved modulus, while also increasing and narrowing the melting temperature. After drawing, the composites were simultaneously delaminated and consolidated using a high pressure water jet to produce dual-component fiber mats with high specific surface area, which was related to the fiber size and rectangular cross-section unique to this process. The tunability of the HDPE and PP fibers produced via this process hold distinct advantages over solvent-based techniques, such as electrospinning, for many high performance applications. (C) 2016 Elsevier Ltd. All rights reserved.