Jaime I. N. Rocha Gomes
University of Minho, Portugal
Jaime Rocha Gomes is a Professor in Textile Chemistry at the University of Minho, Portugal, and since the year 1998 have dedicated my work mainly to microcapsules to be applied to textiles. The main activity consisted in developing processes for microcpasule synthesis and to functionalizing them so as to bind them to the fibers. This laboratory work was followed by a scale up materialized in a spin-off company that has been founded together with the researchers and suported by a venture capital. Later in 2007 the company sold to a belgian company, Devan Chemicals, that also bought the patents. He believes that they the second company in the world in ranking in the PCM market, microcapsules of phase change materials, developed by us. Since then he moved on to nanoparticles, based on the sol-gel process, and incorporated products such as antimicrobial, antimosquito and dyes. These developments made us register a spin-off Ecoticke that will commercialize the antimicrobial and the antimosquito as soon as it has capital investment to do so, and the colored nanoparticles won a national prize and investment to start a company , Ecofoot, that will produce colored nanoparticles very shortly.
The microencapsulation of substances for application to textiles started with fragrances in the 80s, and evolved to more sophisticated applications such as insect repellent, firstly based on fragrances that repel mosquitos, such as eucalyptus and citronella, and then incorporating substances such as DEET and permethrin. However, when applied to textiles, the microcapsules release their content prematurely during washing, making them very sensitive to washing conditions and generally not resistant to more than a few machine wash cycles. With silica nanoparticles, the durability is higher since the product is contained within it their pores and bound by H bonds in case of hydrophilic products such as hydrogen peroxide, and the nanoparticles do not break as in the case of microcapsules, as proven in previous work. Since they have antimicrobial properties, these products are useful for application on textiles such as hospital wear. To fix the nanoparticles to textiles a binder was used. The durability of washing was more than 25 washes. Like these other useful hydrophilic products can be incorporated into silica nanoparticles, with specific properties of interest to textiles such as products that may have insect repellent properties.In this work,one such product fitted the profile and was incorporated into the silica nanoparticles and applied to textiles. They were then tested for mosquito repellency and showed activity even after 10 washes. There was still active product present after 50 washes as determined by colorimetric tests. Results of repellency and durability to washing are presented.