Design of surfactant-free microemulsions composed of n-pentanol, ethanol, and water : application in silica nanoparticle synthesis

Gudelj, Martina (avtor), Kranjac, Marina (avtor), Hajdin, Ita (avtor), Tomšič, Matija (avtor), Cerar, Janez (avtor), Prkić, Ante (avtor), Bošković, Perica (avtor)

This study investigates the formation, physicochemical properties, and applicability of surfactant-free microemulsions (SFMEs) as nanoreactors for the synthesis of silicon dioxide nanoparticles. Surfactant-free systems offer a promising and environmentally benign alternative to traditional microemulsions in which particle formation is governed by surfactants, yet their structural behavior and synthesis mechanisms remain insufficiently understood. A ternary system composed of water, ethanol, and n-pentanol was selected as a model, and its structural organization was analyzed through electrical conductivity, surface tension, and dynamic light scattering (DLS) measurements. The results revealed a broad single-phase region, indicating high miscibility of the components and the formation of dynamically connected polar domains. Electrical conductivity data suggested gradual reorganization of the internal structure without a distinct percolation threshold, while surface tension analysis and the corresponding Gibbs free energies of aggregation (ΔG°) reflected a weaker thermodynamic driving force for aggregation compared to systems containing longer-chain alcohols. DLS measurements confirmed the presence of fluctuating aggregates with hydrodynamic radii between 30 and 85 nm, consistent with literature values for surfactant-free systems. Based on these findings, silica nanoparticles were synthesized within selected compositions of the single-phase region. The resulting particles exhibited predominantly spherical morphology and variable dispersity, reflecting the moderate structural stability of the underlying microemulsion. The synthesized silica nanoparticles typically ranged from approximately 0.9 to 1.2 μm in diameter, reflecting the structural characteristics of the selected SFME compositions. Overall, the results demonstrate that water/ethanol/n-pentanol SFMEs provide new insights into surfactant-free aggregation processes and offer a sustainable route for the synthesis of inorganic nanoparticles.

• Jezik: Angleški jezik
• Ključne besede: SFME, silica nano-particles, dynamic light scattering, electrical conductivity, phase diagrams, TEM
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2025
• Št. strani: 18 str.
• Številčenje: Vol. 13, iss. 12, art. 392
• PID: 20.500.12556/RUL-176543
• UDK: 544.773.3:620.3
• ISSN pri članku: 2304-6740
• DOI: 10.3390/inorganics13120392
• COBISS.SI-ID: 259767811
• Datum objave v RUL: 03.12.2025

Gradivo je del revije

• Naslov: Inorganics
• Skrajšan naslov: Inorganics
• Založnik: MDPI AG
• ISSN: 2304-6740
• COBISS.SI-ID: 520258841

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: SFME, nanodelci silike, dinamično sipanje laserske svetlobe, električna prevodnost, fazni diagrami, TEM