A new approach for measuring the air gap between diaper and baby skin

The air gap between baby skin and top sheet of disposable diapers is the main place where baby's metabolic heat, perspiration, and moisture produced by evaporation of urine stay and transfer. Heat and moisture transfer underneath a diaper are greatly affected by the shape and size of the air gap, therefore, it is of significant importance to explore the air gap between diaper and baby skin for comfort and skin health of babies. Currently, it is still a big problem to accurately measure and characterize the air gap of diaper for scholars. In this article, a new approach to measure the air gap, combining three-dimensional scanning, liquid silicone rubber filling, and image processing methods, was proposed to obtain the shape and size of the air gap between diaper and baby skin by region, for quantitative research on heat and moisture transfer mechanism of diapers. In addition, several indicators, including air volume, air gap thickness, and contact area, as well as clothing area factor of the diaper, were chosen to quantify the air gap size and distributions. After verification of accuracy and repeatability, this new approach can effectively measure the size of the air gap underneath the diaper, and provide a feasible way for exploration on quantitative relationship between thermal and moisture comfort of diapers and their structural design, fit, and diapering habits. Furthermore, diaper designers and baby caregivers can obtain guidelines of diaper structural design, wearing and change to improve the microclimate in the diaper for baby comfort and skin health.