RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity

Vargas, Catalina; Palacio, Daniel A.; Ramírez, Jesús; Pérez-Tijerina, Eduardo; Solís-Pomar, Francisco; Fundara-Cruz, Abel; Bórquez, Rodrigo; Jaramillo, Andrés F.; Oñate, Ángelo; Pino-Soto, Luis; Melendrez, Manuel F.

doi:10.3390/nano16100598

Open AccessArticle

RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity

by

Catalina Vargas

¹,

Daniel A. Palacio

²

,

Jesús Ramírez

³

,

Eduardo Pérez-Tijerina

⁴

,

Francisco Solís-Pomar

⁴

,

Abel Fundara-Cruz

⁴

,

Rodrigo Bórquez

¹

,

Andrés F. Jaramillo

^5,6

,

Ángelo Oñate

⁷

,

Luis Pino-Soto

^1,*

and

Manuel F. Melendrez

^8,*

¹

Departmento de Ingeniería Química, Universidad de Concepción, Edmundo Larenas 219, Box 160-C, Concepción 4070409, Chile

²

Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Casilla 160-C, Concepción 4070409, Chile

³

Facultad de Ingeniería, Universidad San Sebastián, Campus Las Tres Pascualas, Lientur 1457, Concepción 4060000, Chile

⁴

Centro de Investigación en Ciencias Físico Matemáticas, Facultad de Ciencias Físico Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad s/n, San Nicolás de Los Garza 66455, Mexico

⁵

Department of Mechanical Engineering, Universidad de La Frontera, 01145 Francisco Salazar, Temuco 4780000, Chile

⁶

Departamento de Ingeniería Mecánica, Universidad de Córdoba, Cr 6 #76-103, Montería 230002, Colombia

⁷

Departamento de Materiales, Universidad de Concepción, 270 Edmundo Larenas, Box 160-C, Concepción 4070409, Chile

⁸

Facultad de Ciencias de la Rehabilitación y de Calidad de Vida, Universidad San Sebastián, Campus Las Tres Pascualas, Lientur 1439, Concepción 4060000, Chile

^*

Authors to whom correspondence should be addressed.

Nanomaterials 2026, 16(10), 598; https://doi.org/10.3390/nano16100598

Submission received: 6 March 2026 / Revised: 17 April 2026 / Accepted: 20 April 2026 / Published: 13 May 2026

(This article belongs to the Section Nanofabrication and Nanomanufacturing)

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Abstract

Water stress is intensifying worldwide, increasing the need for efficient desalination and water purification technologies. Although commercial nanofiltration membranes such as NF90 exhibit high separation performance, their transport properties remain governed by permeability–selectivity trade-offs, and their surface characteristics offer limited tunability for application-specific requirements. Here, a commercial NF90 polyamide thin-film composite nanofiltration membrane was surface modified by depositing ultrathin ZnO coatings via RF sputtering (30–120 s) and evaluated in terms of surface properties, water permeate flux, and NaCl rejection. X-ray diffraction confirmed the formation of crystalline Wurtzite ZnO with preferential (002) orientation. ZnO deposition markedly increased surface hydrophobicity, raising the water contact angle from 52.5 ± 2.0° for the unmodified membrane to 140.4 ± 3.9° after 120 s of deposition. Hydraulic performance decreased after modification, with water permeate flux reduced by approximately 47–50% relative to pristine NF90. In contrast, NaCl rejection increased with ZnO deposition time, particularly at lower operating pressures, and tended to plateau at higher pressures. The Spiegler–Kedem model accurately described experimental rejection-flux behavior. Overall, RF sputtering of ZnO is a feasible post-fabrication route to tune NF membrane selectivity, while introducing a clear trade-off with permeate flux.

Keywords: nanofiltration; NF90 thin-film composite membrane; ZnO RF sputtering; water contact angle; Spiegler–Kedem model

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MDPI and ACS Style

Vargas, C.; Palacio, D.A.; Ramírez, J.; Pérez-Tijerina, E.; Solís-Pomar, F.; Fundara-Cruz, A.; Bórquez, R.; Jaramillo, A.F.; Oñate, Á.; Pino-Soto, L.; et al. RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity. Nanomaterials 2026, 16, 598. https://doi.org/10.3390/nano16100598

AMA Style

Vargas C, Palacio DA, Ramírez J, Pérez-Tijerina E, Solís-Pomar F, Fundara-Cruz A, Bórquez R, Jaramillo AF, Oñate Á, Pino-Soto L, et al. RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity. Nanomaterials. 2026; 16(10):598. https://doi.org/10.3390/nano16100598

Chicago/Turabian Style

Vargas, Catalina, Daniel A. Palacio, Jesús Ramírez, Eduardo Pérez-Tijerina, Francisco Solís-Pomar, Abel Fundara-Cruz, Rodrigo Bórquez, Andrés F. Jaramillo, Ángelo Oñate, Luis Pino-Soto, and et al. 2026. "RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity" Nanomaterials 16, no. 10: 598. https://doi.org/10.3390/nano16100598

APA Style

Vargas, C., Palacio, D. A., Ramírez, J., Pérez-Tijerina, E., Solís-Pomar, F., Fundara-Cruz, A., Bórquez, R., Jaramillo, A. F., Oñate, Á., Pino-Soto, L., & Melendrez, M. F. (2026). RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity. Nanomaterials, 16(10), 598. https://doi.org/10.3390/nano16100598

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RF-Sputtered ZnO Nano-Coatings on Polyamide Thin-Film Composite Membranes for Tuned Nanofiltration Selectivity

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