Fig. 4.

In vitro degradation characterizations of hot stretched nanoyarns with different SF/PLLA mass ratio. (a) SEM observation at different predetermined time point throughout 8 weeks. Scale bars ​= ​2.5 ​μm for SEM images, scale bars ​= ​500 ​nm for inserted images with blue box. Quantitative measurements of mass loss rate (b) and pH value (c) at different predetermined time points throughout 8 weeks. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)