Structuro-functional tuning of transparent PVA/laponite nanocomposite xerogels via controlled freeze–thaw processing

• Controlled freeze–thaw processing produces transparent PVA/laponite xerogel films. • Laponite loading (1–5 wt %) and cycle number (3–7) tune crystallinity and network density. • Optimized composites show up to 76.3 MPa tensile strength and 4.2 GPa elastic modulus. • Well‑dispersed laponite enhances thermal stability, shifting degradation onset by ∼10 °C. • Xerogels retain high optical clarity while exhibiting rapid swelling and slow hydrolytic degradation. Polyvinyl alcohol (PVA) xerogel films reinforced with Laponite (LAP) nanoparticles were prepared via controlled freeze–thaw physical crosslinking to produce transparent, mechanically robust, and thermally stable nanocomposite xerogels. We systematically varied Laponite loading (1–5 wt.%) and the number of freeze–thaw cycles (3, 5, 7) to evaluate their effects on morphology, crystallinity, optical clarity, mechanical performance, swelling, and thermal stability. Well-dispersed Laponite promoted formation of submicrometer crystalline domains and a homogeneous microstructure, as confirmed by FE‑SEM and XRD. ATR‑FTIR crystallinity indices ( A 1137 / A 1085 ) increased with optimized clay content and cycle number, reaching ∼0.48 for the PVA/LAP sample processed with 7 cycles. The addition of Laponite improved thermal stability (onset degradation shifted ≈10 °C at 5 wt.% LAP) and enhanced mechanical properties, with maximum tensile strength and elastic modulus of 76.3 MPa and 4.2 GPa observed at 3 wt.% LAP and 7 cycles. Swelling and long‑term hydrolytic tests showed rapid water uptake and limited mass loss (<25% over 42 days), indicating network stability. These results demonstrate that freeze–thaw processing combined with low‑loading Laponite enables tunable, transparent PVA xerogels suitable for applications requiring a balance of optical clarity, mechanical strength, and thermal resilience.