Incorporation of N,N,‐diethyl‐meta‐toluamide within electrospun nylon‐6/6 nanofibers

Abstract

Encapsulation of insect repellents is a key method of controlling their delivery and limiting unnecessary exposure to the wearer. Common topical repellents suffer from short lifetimes resulting in the need to frequently re‐apply to retain effectiveness. Herein, a strategy is employed whereby N,N,‐diethyl‐meta‐toluamide (DEET) is incorporated within electrospun nylon 6/6 nanofibers. Electrospinning from polymer solutions containing up to 50 wt% DEET relative to nylon has no detrimental effect on the fiber morphology and thermal analysis shows the final fibers can contain up to 29 wt% DEET. The effect of varying the concentration of nylon electrospinning solution on the fiber morphology and the retention of DEET is discussed. The rate constant for DEET release is calculated at room temperature and is used to estimate the estimated repellency of the fibers. The lifetime depends on the weight of material and the concentration of DEET, where the active lifetime for a lightweight fabric is estimated to be >200 h. We demonstrate electrospinning as a facile means to incorporate DEET within a polymer matrix and control its evaporation and highlight the possibility for the preparation of fabrics and textiles with long‐lasting, active insect protection.

Long-Term Insect Repellent Electrospun Microfibers from Recycled Poly(ethylene terephthalate)

“…Fiber diameter varied greatly for all fibers synthesized, as seen in Figure . Our previous studies with repellent-loaded nylon fibers produced nanofibers (100–500 nm), , while recycled PET allowed for microfibers (0.6–4.0 μm) to be obtained. Fiber morphology was dependent on the insect repellent type, combination, and conservation.…”

“…Fibers were subjected to increasing temperature from room temperature to 600 °C at 10 °C/min to evaluate the mass loss within the ramp, Figure E,F. The decrease in fiber mass at 250 °C was attributed to the loss of insect repellent, from which the percentage of repellent retained was calculated . After electrospinning, DEET rPET fibers retained 80.0–97.5% of DEET from the initial electrospinning solution, Table .…”

“…Electrospinning polymer materials have been effective in drug delivery and extending the release of repellents. , The synthesized fibers can quickly be tested for the composition as well as release of repellents. Monofilament nylon nanofibers were shown to have extended release of DEET with calculated half-life as high as 70 h . Picaridin has also been utilized in the synthesis of fibers and was observed to have extended release of the repellent .…”

Sustainable Electrospun Poly(l-lactic acid) Fibers for Controlled Release of the Mosquito-Repellent Ethyl Butylacetylaminopropionate (IR3535)

“…Electrospinning, as a versatile fabrication technique, allows for the production of continuous fibers from solutions or melts, predominantly polymers. The continuous fibers have diameters varying from several micrometers down to a few nanometers, depending on the involved material properties and processing parameters. − Nanofibers of polyamide, e.g., used for production of fabrics, containing insect-repellents were successfully produced by electrospinning, − demonstrating the feasibility of this approach. For example, the repellents 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester (picaridin) and N , N -diethyl-3-methylbenzamide (DEET) were incorporated into polyamide 66 (PA 66), with these fibers containing up to 50 m% of the repellent.…”

“…For example, the repellents 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester (picaridin) and N , N -diethyl-3-methylbenzamide (DEET) were incorporated into polyamide 66 (PA 66), with these fibers containing up to 50 m% of the repellent. For the case of picaridin-loaded fibers, release at 100 °C was still detected after 300 min, with an extrapolated half-time of about 130 h at 20 °C, while for DEET-containing fibers, repellency for about 200 h was estimated, exceeding, time-wise, common topical application. , In another work, the insecticide (3-phenoxyphenyl)­methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate (permethrin) was added into a polyamide 6 (PA 6) solution for electrospinning, with the obtained fibers subsequently dip-coated on plasma-treated fiber surfaces . The obtained permethrin-treated fabrics showed repellency and led to a higher percentage of mosquito escape compared to untreated preparations.…”