Mosquito repellent thermal stability, permeability and air volatility

Area of Science:

• Chemical Engineering
• Materials Science
• Entomology

Background:

• Mosquito repellent effectiveness relies on controlled vapor release, influenced by evaporation rates.
• Topical application and wearable devices both depend on the repellent's volatility for efficacy.
• Gravimetric techniques are crucial for studying repellent evaporation and release mechanisms.

Purpose of the Study:

• To investigate the direct evaporation of liquid mosquito repellents.
• To analyze repellent permeation through polymer films.
• To determine the release rates of repellents from microporous polyethylene matrices.

Main Methods:

• Utilized gravimetric techniques to measure evaporation rates of various liquid repellents.
• Investigated repellent permeation through polymer films.
• Examined repellent release from extruded microporous polyethylene strands.

Main Results:

• Repellents were ranked by volatility: ethyl anthranilate (most) to Icaridin (least).
• Experimental volatility (S_A) values ranged from 0.015 to 0.838 mPa·m²·s^-1 at 50°C.
• Release rates from polyethylene matrices mirrored the volatility ranking, with a controlled low release.

Conclusions:

• Ethyl butylacetylaminopropionate and Icaridin exhibit low volatility and high stability, making them suitable for long-lasting wearable devices.
• Wearable repellent devices (anklets, bracelets) offer potential protection against mosquito bites in malaria-endemic areas.
• Controlled release from microporous materials enhances the longevity and effectiveness of repellents.