Effect of coating on the mechanical properties of electrospun poly(3-hydroxybutyrate) materials with targeted fibers alignment

Abstract

Understanding the mechanical behavior of electrospun materials and how to control it is important and valuable in terms of their future applications. That is why, in this study, materials with controlled fibers alignment and desired mechanical properties were fabricated by electrospinning of poly(3-hydroxybutyrate) (PHB) onto three types of rotating collectors – drum (smooth), blade and grid (patterned). In addition, by controlling the collector rotation speed and by coating of the PHB mats with chitosan or cellulose acetate, purposely tailored fibers alignment and targeted design of the materials were achieved. Further, the detailed surface morphology, thermal behavior and crystallinity of the PHB materials were characterized by SEM, DSC and XRD. It was demonstrated that patterned collectors had a significant impact on fibers alignment only at lower rotation speed, whereas with the increase in the collector speed the fibers alignment increased in the direction of collector rotation. The materials strength was evaluated by tensile tests and indicated that PHB materials fabricated at lower collector rotation speed exhibited isotropic mechanical properties, whereas those at higher collector rotation speed – anisotropic. In addition, coating of PHB materials with chitosan or cellulose acetate enhanced their mechanical properties. Hence, this study demonstrates the possibilities for fabrication of electrospun materials with desired fibers alignment and thus, with targeted mechanical properties.