Scientific exploration unfolds as six individuals don warm garments to delve into the mysteries of perspiration
Unveiling the Mysteries of Sweat: A Game-Changer in Cooling Technologies
A groundbreaking study led by Konrad Rykaczewski, in collaboration with hydration specialist Stavros Kavouras, has shed light on the intricate process of sweat formation and its implications for the development of advanced clothing and cooling technologies.
The study reveals that sweat forms a continuous film on human skin, primarily due to its secretion from numerous active sweat pores densely distributed across the skin surface. This film is influenced by the skin’s microtexture and hydrophilic properties, which promote sweat spreading and adhesion, as well as sweat composition, including ions and organic compounds, which can interact with skin and sensing materials.
This natural mechanism underpins innovative applications in cooling technologies and advanced fabrics. For instance, bioinspired microfluidic devices mimic sweat transport and film formation to enhance efficient sweat collection and evaporation, improving human cooling. Wearable sensors integrate sweat collection membranes, such as Janus membranes with asymmetric wettability, that guide sweat into microchannels, enabling controlled evaporation and heat dissipation.
Advanced fabrics engineered with microtextured or porous surfaces emulate skin’s sweat pore distribution or wettability, promoting rapid sweat spreading and evaporation to maintain wearer comfort. Integration of covalent organic frameworks or similar porous materials in textiles can provide sensitive responses to sweat, enabling colorimetric or electronic feedback on sweat and body temperature, which can be used for adaptive cooling or health monitoring.
Moisture-wicking fabrics utilize principles learned from sweat film formation to transport sweat away from skin in a controlled manner, accelerating evaporation and reducing heat load. When the stratum corneum, the outermost layer of dead skin cells, becomes saturated, sweat accumulates on the surface. As it cools, the film of sweat evaporates quickly and leaves a thin layer of salt, facilitating the penetration of sweat into the stratum corneum.
The discovery of the continuous film of sweat formation could help in the development of fabrics and technologies that improve body cooling. To observe the process, the study was conducted on six volunteers who were dressed in heated suits and sat in reclining chairs with waterproof paper to prevent sweat from reaching heated blankets. The "tide" of sweat saturates the stratum corneum, the outermost layer of dead skin cells, like a sponge.
The study focused primarily on the forehead due to its microhairs that aid in evaporation. Armpits, arms, and other zones have different concentrations of glands, hairs, and odors compared to the forehead. The heated suits transformed the volunteers into "human burritos" to simulate the body's response to heat.
In a study published in the Journal of the Royal Society Interface, it was observed that sweat does not come out of the skin in small isolated drops, but accumulates in the pores, forms small pools, and then creates a continuous film, spreading like a water sheet over the skin. Understanding this mechanism can help create better cooling technologies, as moisture alone does not cool the skin; it's evaporation that cools the skin.
Rykaczewski explained that the continuous film of sweat formed over the skin due to the process starting at the micro level in the sweat glands in the hypodermis. These cutting-edge technologies leverage sweat’s natural properties to improve thermal comfort and health management.
- The groundbreaking study on sweat formation has opened up opportunities for the development of health-and-wellness products, such as wearable sensors that integrate sweat collection membranes for controlled evaporation and heat dissipation, benefiting fitness-and-exercise enthusiasts by improving their thermal comfort.
- In the field of science and technology, the discovery of the continuous film of sweat formation could lead to advancements in cooling technologies, given its implications for enhancing the efficiency of moisture-wicking fabrics and creating bioinspired microfluidic devices, offering a game-changer in health management and fitness-and-exercise.
