Hard elastic fibers are a kind of special fibers that are not easy to deform under low stress, but have better elasticity under higher stress, especially at lower temperatures. Most of the fibers are processed by melt spinning under special conditions. They have high elasticity, high modulus, excellent elasticity in low temperature, high temperature recovery and can form micro-pores when stretched. To get researchers’ attention enough, this paper firstly reviewed characteristics and types of hard elastic materials, then summarized formation mechanism in detail, further reviewed the current research status and provides a prospect for their possible future development trends. The aim is to provide assistance for an in-depth research of hard elastic fibers.

To enhance the charge transport performance of poly(9,9-di-n-octylfluorene) (PFO) in polymer light-emitting diodes (PLEDs), the electron transport behaviors of PFO blended with polystyrene (PSt) were investigated. Electron-only (EO) devices were fabricated using a solution process to assess electron transport performance. The results demonstrated that blending PFO with a minority of PSt induced β-phase formation and phase separation upon annealing, contributing to improved electron transport properties. EO measurements revealed that the electron mobility of PFO/PSt blends (PSt: 30wt%, 40%) after annealing was higher than that of pure PFO in both states.