Polyurethane Aerogels with Tunable Porosity for Enhanced Electrochemical Sensing of Lactic Acid in wines

Polyurethane (PU) aerogels were investigated as functional membranes in potentiometric sensors for lactic acid. By tailoring the aerogel architecture (porosity, bulk density, pore size, and specific surface area), marked differences in electrochemical behavior were observed. The potentiometric response arises from the combined effects of weak adsorption, non-specific electrostatic interactions, and diffusion of lactate within the porous polymeric matrix. Among the materials studied, PU-2, with the highest bulk density (0.141 g/cm 3 ) and largest specific surface area (294 m 2 /g), showed the most favorable analytical performance, achieving a limit of detection of 1.32 × 10 -6 M, a sensitivity of 8.45 mV/dec, and outstanding stability with only 2% signal loss after four days. In contrast, PU-18, characterized by the lowest density (0.102 g/cm 3 ) and the largest pore size (722 nm), displayed a higher detection limit (7.22 × 10 -5 M) and a 24.33% signal loss. These findings reveal a clear structure–function relationship: smaller pores and larger surface areas favor faster stabilization and stronger potentials, while larger pores and reduced surface area compromise sensitivity and stability. Compared with conventional PVC-based membranes, PU aerogels offer a tunable and scalable alternative, combining chemical versatility with competitive analytical performance, particularly in terms of detection limits and sensitivity, compared to traditional PVC-based membranes. The structure–function relationships described here may be extended to other analytes, sensing platforms, or beverages underscoring the versatility of polyurethane aerogels for use in advanced electrochemical devices. • Polyurethane aerogels were tested as novel membranes for potentiometric sensors. • Aerogel porosity, density, and surface area strongly influenced sensor performance. • Higher porosity and larger pores led to reduced sensitivity and higher detection limits. • Denser aerogels with higher surface area improved sensitivity and long-term stability. • Optimized aerogel membranes outperformed conventional materials in lactic acid sensing.