A novel system for enhancing the mechanical properties of PVA/PAA cross-linked nanofibrous hybrid composites incorporating POSS was developed in this study. An electrospinning and followed by simple heat-treatment strategy was used to prepare nanofibrous PVA/PAA composite hydrogels. The mechanical properties have been dramatically improved by a heat-treatment as well as an incorporated nanohybrid POSS. The PVA/PAA composite nanofibers exhibited 2.3 times higher tensile strength and 4.4 times higher Young's modulus after heat-treatment, suggesting that the elasticity of these nanofibers was reinforced by the formation of chemically cross-linked networks. Moreover, compared to the heat-treated PVA/PAA nanofibers without POSS, the PVA/PAA/POSS hybrid nanofibers (POSS content similar to 0.6 wt.%) showed 3.3 times improvement in Young's modulus and 2.0 times increase in tensile strength after heat-treatment at 160 degrees C for 30 min. This suggests that the elasticity of these nanofibers were dramatically reinforced by the incorporated POSS nanoparticles as well as chemically cross-linked networks via an ester bond formation between -OH groups of PVA and -COOH groups in PAA. (C) 2015 Elsevier Ltd. All rights reserved.