Microcapsules containing citronella essential oil were prepared by complex coacervation and applied to cotton textiles in order to study the repellent efficacy of the obtained fabrics. Citronella released from treated textiles was indirectly monitored by the extractable content of its main components. Repellent activity was assessed by exposure of a human hand and arm covered with the treated textiles to Aedes aegypti mosquitoes. Fabrics treated with microencapsulated citronella presented a higher and longer lasting protection from insects compared to fabrics sprayed with an ethanol solution of the essential oil, assuring a repellent effect higher than 90% for three weeks. Complex coacervation is a simple, low cost, scalable and reproducible method of obtaining encapsulated essential oils for textile application. Repellent textiles were achieved by padding cotton fabrics with microcapsules slurries using a conventional pad-dry method. This methodology requires no additional investment for textile finishing industries, which is a desirable factor in developing countries.

Functional textiles are being developed in order to provide fabrics with new properties and added value. They can be obtained either by using new chemical fibers or by incorporating functional agents to conventional fabrics. Microencapsulation is an effective method to protect these functional agents from reactions with moisture, light, and oxygen. If a fabric is treated with microencapsulated functional agents, higher durability of functionality is expected. This article reports the development and testing of two types of microcapsules containing essential oils for application in cotton fabrics. Microcapsules were obtained by complex coacervation using gelatin and arabic gum or by encapsulation in yeast cells in order to increase the durability of fragrances in textiles. Microcapsule characterization, such as particle size and morphology, was carried out for different oils to polymer ratios and hardening agents to polymer ratios. Padding and coating were tested as application methods. The morphology, durability of the fragrance, and laundering properties of the treated fabrics were investigated. The use of an electronic nose to measure the fragrance release from microcapsules was also evaluated. Gelatin—arabic gum microcapsules increased the durability of the fragrance on the treated fabrics and withstood one wash cycle. Fabrics treated with yeast cell microcapsules presented low fragrance intensity before washing. The fragrance was not detectable after laundering, even though the microcapsules could still be observed on the fabric.

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