Valentina Trovato1, Alessio Mezzi2, Marco Brucale3, Giuseppe Rosace4, Maria Rosaria Plutino5. 1. Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, 24044 Dalmine, BG, Italy. Electronic address: valentina.trovato@unibg.it. 2. Institute for the Study of Nanostructured Materials, ISMN - CNR, via Salaria Km 29.3, 00015 Monterotondo stazione, Rome, Italy. Electronic address: alessio.mezzi@cnr.it. 3. Institute for the Study of Nanostructured Materials, ISMN - CNR, via P. Gobetti, 101 40129 Bologna, Italy. Electronic address: marco.brucale@ismn.cnr.it. 4. Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, 24044 Dalmine, BG, Italy. Electronic address: giuseppe.rosace@unibg.it. 5. Institute for the Study of Nanostructured Materials, ISMN - CNR, Palermo, c/o Department of ChiBioFarAm, University of Messina, Viale F. Stagno d'Alcontres 31, Vill. S. Agata, 98166 Messina, ME, Italy. Electronic address: mariarosaria.plutino@cnr.it.
Abstract
HYPOTHESIS: The broad detection properties of alizarin, not only concerning pH variations but also temperature, glucose and health-like relevant cations alterations, make it a molecule of great scientific interest, particularly for developing multifunctional wearable sensors. EXPERIMENT: Herein, the alizarin red S dyestuff is bonded with trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane, as a sol-gel precursor, to functionalize cotton fabrics. The chemical and structural properties of both plain and silane-functionalized dyestuffs are investigated in solution and solid-state by several chemical-physical characterization techniques. FINDINGS: The hybrid dyestuff characterization reveals the epoxy ring-opening of the silica precursor, leading to covalent linkages to the sulfonic group of alizarin, which retains its structure during the sol-gel reaction. The silane-functionalized halochromic dyestuff shows similar halochromic behaviour as its pristine solution in the investigated pH range, thus demonstrating a color shift from yellow to red due to the protonation/deprotonation reversible mechanism of the chromophore. The reversibility and repeatability of pH-sensing properties of treated cotton fabrics are confirmed by diffuse reflectance and CIELAB color space characterizations. Cotton fabric functionalized with alizarin-containing sol-gel coating shows excellent durability of halochromic properties, thus emerging as a versatile platform for stimuli-responsive materials.
HYPOTHESIS: The broad detection properties of alizarin, not only concerning pH variations but also temperature, glucose and health-like relevant cations alterations, make it a molecule of great scientific interest, particularly for developing multifunctional wearable sensors. EXPERIMENT: Herein, the alizarin red S dyestuff is bonded with trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane, as a sol-gel precursor, to functionalize cotton fabrics. The chemical and structural properties of both plain and silane-functionalized dyestuffs are investigated in solution and solid-state by several chemical-physical characterization techniques. FINDINGS: The hybrid dyestuff characterization reveals the epoxy ring-opening of the silica precursor, leading to covalent linkages to the sulfonic group of alizarin, which retains its structure during the sol-gel reaction. The silane-functionalized halochromic dyestuff shows similar halochromic behaviour as its pristine solution in the investigated pH range, thus demonstrating a color shift from yellow to red due to the protonation/deprotonation reversible mechanism of the chromophore. The reversibility and repeatability of pH-sensing properties of treated cotton fabrics are confirmed by diffuse reflectance and CIELAB color space characterizations. Cotton fabric functionalized with alizarin-containing sol-gel coating shows excellent durability of halochromic properties, thus emerging as a versatile platform for stimuli-responsive materials.