Figure 1. Dynamics of the metallic conductive filament growth in the poly (vinyl alcohol) (PVA) based memristor. (a) Schematics presenting the structure of the PVA based memristor with mechanical flexibility and biodegradability, and its potentials as an artificial synapse for hardware-based eco-friendly neural networks. (b) A schematic showing the PVA based memristors with a planar structure. Three types of the devices with the different polymer molecular weights (Mws) (130000, 23000, and 10000 gmol-1) were prepared. An inset image shows a microscopic photograph of the device. (c) Active surfaces of the device according to the resistance states. Each surface was investigated using a field-emission scanning electron microscope (scale bar, 1 μm).