Polyelectrolyte-Assisted Immobilization of Oil-Based Nanocapsules on Cotton Fabric Yuwanda Iamphaojeen, A Avinash P. Manian, B Tom Wright, B Barnaby Caven, B Thomas Bechtold, B and Punnama Siriphannon A,C,D A Functional Nanostructured Materials Laboratory, College of Nanotechnology, King Mongkut’s Institute of Technology Ladkrabang, Chalongkrung Road, Bangkok 10520, Thailand. B Research Institute of Textile Chemistry and Textile Physics, University of Innsbruck, Ho ¨ chsterstraße 73, A-6850, Dornbirn, Austria. C Department of Chemistry, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang, Chalongkrung Road, Bangkok 10520, Thailand. D Corresponding author. Email: punnama.si@kmitl.ac.th Poly(diallyldimethylammonium chloride)-encapsulated n-octadecane nanocapsules (PDDA-Oc-cap) were easily immo- bilized on cationized cotton at ambient temperature using poly(4-styrenesulfonic acid) (PSS) as a binder. The cationized cotton was first treated with 1–50 mM of PSS and then soaked in the PDDA-Oc-cap emulsion in order to obtain stepwise PSS/PDDA-Oc-cap coating layers on the cationized cotton (Cat-cot/PSS/PDDA-Oc-cap). The negative molecules of PSS binder spontaneously attached to the cationized cotton and then acted as negative sites for further immobilization of positively charged PDDA-Oc-cap via electrostatic interaction. Uniform globular particles of PDDA-Oc-cap were observed on the surfaces of Cat-cot/PSS/PDDA-Oc-cap samples in the field-emission scanning electron microscopy images. The positive zeta potential was obtained in the Cat-cot/PSS/PDDA-Oc-cap samples due to the deposition of the positively charged PDDA-Oc-cap on cotton fabric. In addition, the Cat-cot/PSS/PDDA-Oc-cap samples preferentially adsorbed anionic dye eosin B over cationic dye methylene blue. Higher PSS concentrations used in the treatment resulted in higher quantities of PDDA-Oc-cap immobilized on the fabrics, resulting in the concomitant increase of eosin B adsorption. These results suggested that the PSS-assisted immobilization was an efficient alternative method for textile finishing. Manuscript received: 28 November 2015. Manuscript accepted: 31 January 2016. Published online: 4 March 2016. Introduction Because textiles are one of the basic human needs for livelihood, the demand for textile products rapidly increases with the massive growth of human population, leading to highly competitive markets. Some competitive strategies employed involve either lower prices or the fabrication of value-added products. Textile finishing process is one of the most common and attractive methods to create value-added textile products with various special properties obtained from finishing agents e. g. fragrances, [1–3] skin softener, [4] flame retardants, [5,6] phase- change material, [7–9] insect repellents, [10,11] and antimicrobial agents. [12–14] Various conventional textile finishing methods are commonly used in the textile industry e.g. pad–dry–cure, dip coating, spray coating, and impregnation. [15] However, the attachment of some finishing agents onto textiles obtained from conventional methods is somewhat poor, resulting in performance drop after prolonged usage. [13] In order to overcome this drawback, many research groups have studied and developed various chemical treatments for textiles before conventional finishing e.g. grafting of cotton fabric with monochlorotriazinyl-b-cyclodextrin, [11] cross-linking of cotton fabrics with citric acid, [4] cationizing of cotton fabrics with (3-chloro-2-hydroxypropyl)trimethylammonium chloride. [14] A previous study has shown that an effective finishing method for immobilization of ZnO nanoparticles on cationized cotton was proposed using poly(4-styrenesulfonic acid) (PSS) polyelectrolyte as a binder. [12] The PSS polyelectrolyte could electrostatically interact with the Zn 2þ precursors, which hydro- thermally grew to ZnO nanoparticles immobilized on cotton fabric, resulting in excellent attachment between the ZnO nanoparticles and cotton surface. This method is suitable for cotton finishing involving charged molecules and/or particles, but not oil-based finishing agents e.g. fragrances, insect repel- lents, and phase-change materials. Therefore, the oil-based finishing agents would be encapsulated within the thin shell of cationic polyelectrolytes by a soft-solution technique as described in the previous work. [16] A facile and effective method for the immobilization of nanocapsules containing the oil-based finishing agent, n-octadecane, on cotton fabric was proposed in this work. The effect of PSS concentration used in the treatment system was investigated. CSIRO PUBLISHING Aust. J. Chem. http://dx.doi.org/10.1071/CH15746 Journal compilation Ó CSIRO 2016 www.publish.csiro.au/journals/ajc Full Paper