Interaction between Poly(vinyl alcohol) and Layered Double Hydroxide (LDH) Particles with Different Topological Shape and Their Application in Electrospinning

To explore the influence of filler topological shape on the rheological behavior of poly(vinyl alcohol) (PVA) aqueous solution, three kinds (nanosized layered crystals, microsized layered crystals, and nanoscrolls) of layered double hydroxides (LDHs) were synthesized. Except for nanosized layered crystals, both LDH microsized layered crystals and nanoscrolls filled system showed distinct "N" shape viscosity curves with increasing LDH loadings. Notably, the one-dimensional LDH nanoscrolls could increase or decrease the viscosity of PVA solution by only changing the loadings. With combined theoretical calculation with dynamic mechanical analyses, the adsorbed state of PVA chains on surface of the three LDH particles was proposed, in which PVA chains exhibited various adsorbed states due to different interactions between PVA chains and LDH particles with disparate topological shape. Taking the advantage of remarkable rheological modulation and adsorption capacity, LDH nanoscrolls were introduced into PVA aqueous solution to broaden effectively its electrospinnable concentration window from 8.5-11.3 wt % to 6.5-18.0 wt %. More importantly, the adsorption capacity of LDH nanoscrolls was well preserved in the as-electrospun composite nanofibers, implying a superior adsorbent for methyl orange from wastewater was obtained.