Porous Hygroscopic Superabsorbent Polymer Fabricated via High-Speed Shearing Homogenization of High Internal Phase Emulsion for Humidity Regulation

Abstract

Humidity regulation plays a critical role in human comfort, industrial processes, and art preservation. Developing solid hygroscopic materials that simultaneously achieve high moisture uptake, low-temperature regeneration, and rapid adsorption kinetics remains a significant challenge. Herein, we report a porous hygroscopic superabsorbent polymer, porous poly(acrylic acid-co-sodium acrylate) (PPAANa), synthesized via high internal phase emulsion (HIPE) templating coupled with high-speed shearing homogenization and a polymerizable macromolecular surfactant. At 25°C, PPAANa achieves a moisture uptake of 0.76 g g⁻¹ within 45 min at 70% relative humidity (RH) and 1.53 g g⁻¹ within 105 min under 90% RH, demonstrating high capacity and fast kinetics. Moreover, 90% of the adsorbed water was released within 20 min under a low regeneration temperature of 60°C (20% RH), underscoring its fast and energy-efficient desorption performance. Additionally, a small dosage of PPAANa (0.125 g L⁻¹) reduces the RH from 90% to 58% within 1 h at 25°C. Conversely, when pre-loaded with 0.25–0.45 g g⁻¹ of water, it raises the RH from 30% to a tunable range of 42%–59% under the same conditions. These results highlight PPAANa as a promising polymer desiccant for energy‑efficient and intelligent indoor humidity regulation.