ARTICLE Surface modification of ZnO quantum dots coated polylactic acid knitted fabric for photocatalytic application Rivaldo Leonn Bezerra Cabral 1 | Felipe Mendonça Fontes Galv~ ao 1 | Kesia Karina Oliveira de Souto Silva 1 | Brenno Henrique Silva Felipe 2 | Nivaldo Freire de Andrade Neto 3 | Pierre Basílio de Almeida Fechine 4 | Andrea Zille 5 | Suyeon Kim 6 | José Heriberto Oliveira do Nascimento 1,2 1 Postgraduate Program in Textile Engineering, Center of Technology, Federal University of Rio Grande do Norte, Rio Grande do Norte, Brazil 2 Postgraduate Program in Mechanical Engineering, Center of Technology, Federal University of Rio Grande do Norte, Rio Grande do Norte, Brazil 3 Department of Materials Engineering, Center of Technology, Federal University of Rio Grande Do Norte, Rio Grande do Norte, Brazil 4 Department of Analytical Chemistry and Physical Chemistry, Science Center, Federal University of Cear a, Cear a, Brazil 5 Center for Textile Science and Technology (2C2T), University of Minho, Guimar~ aes, Portugal 6 Department of Engineering, Pontificia Universidad Cat olica del Perú, Lima, Peru Correspondence Rivaldo Leonn Bezerra Cabral and José Heriberto Oliveira do Nascimento, Postgraduate Program in Textile Engineering, Center of Technology, Federal University of Rio Grande do Norte, 59072970, Rio Grande do Norte, Brazil. Email: systemriva38@gmail.com and joseheriberto@ct.ufrn.br Funding information Coordenaç~ ao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnol ogico (CNPq) Abstract In this work, ZnO quantum dots (ZnOQD) were synthesized by Sol–gel synthe- sis and impregnated on polylactic acid (PLA) knitted fabric through self- assembly of different cycles from layer-by-layer (LBL) using cationic agent Poly(diallydimethylammonium chloride) (PDDA). Then, morphological, chemi- cal and photocatalytic properties were studied. The results demonstrate that the synthesis provided 8 nm Wurtzite-type ZnO nanoparticles. In addition, X-ray photoelectron spectroscopy (XPS) spectra, X-ray diffraction (XRD) and scanning electron microscopy (SEM) proved the inclusion of ZnOQD on the surface of PLA matrix, which allowed the evaluation of its photocatalytic properties, there- fore, coated PLA with five cycles of ZnOQD obtained the best result for degrading 85% of the dye Rhodamine B (RhB) in 360 min under UV radiation, in addition to its reusability for another five cycles of photocatalytic activity. KEYWORDS layer-by-layer, nanoparticles, photocatalytic, polylactic acid, quantum dots, ZnO 1 | INTRODUCTION In the last few years, the use of dyes in the textile and leather industry has declined, but even so their produc- tion remains large due to the applications of the world of fashion, interior design and plastics. It is estimated that more than 800,000 tons, representing 3000 types of dyes, are produced annually for applications in textile processes, and the lack of efficiency and optimization of these production processes causes the release of about 10%–15% of these dyes in the environment as generators of complex textile effluents. 1,2 As a result, up to 84,000 tons of dyes can be lost in water, 90 million cubic meters of water are used annually in the production of these dyes as well as in their application in the textile and leather industries. These processes end up being Received: 10 November 2021 Revised: 16 February 2022 Accepted: 17 February 2022 DOI: 10.1002/app.52381 J Appl Polym Sci. 2022;e52381. wileyonlinelibrary.com/journal/app © 2022 Wiley Periodicals LLC. 1 of 14 https://doi.org/10.1002/app.52381