Ionic Liquid‑Functionalized Geopolymer Microsystems: Toward Biomimetic In‑Memory Processing

Abstract

We present a microscale geopolymer–ionic liquid (GP–IL) system engineered for in‑memory biomimetic processing. Using a soft‑lithography approach, spherical geopolymer resonators (Ø 50–200 µm) were functionalized with 1‑butyl‑3‑methylimidazolium hexafluorophosphate (BMIM·PF₆) at 20 wt % via room‑temperature impregnation. Morphological studies (SEM, µ-FTIR) confirm uniform IL confinement within the geopolymer network. Electrical characterization of Au/GP–IL/Au microjunctions reveals forming‑free, bipolar resistive switching with set/reset voltages of +0.35 V/–0.30 V and on/off ratios >10⁴. Synaptic behaviors—including paired‑pulse facilitation/depression and spike‑timing‑dependent plasticity—are emulated with energy consumption <3 pJ per event. Moreover, a 4×4 GP–IL crossbar array demonstrates pattern recognition of handwritten digits with 90 % accuracy using an on‑device learning algorithm. These results highlight the potential of IL‑functionalized geopolymer microsystems as sustainable, low‑voltage platforms for integrated neuromorphic hardware in edge‑AI and tactile sensing applications.