Electrostatic sprays for sunless tanning of the human body

Abstract

Electrostatic-induction charging nozzles were incorporated into a 4.7-m/sup 3/ dielectric spray chamber to create an efficient method for uniformly applying topical coatings to human subjects. One specific commercial use of the device is applying water-based cosmetic tanning formulations containing dihydroxyacetone (DHA) and aloe vera. Other foreseen uses of the system include applying medicinal and decontaminant sprays (e.g., antibiotics, antitoxins, disinfectants, sanitizers, etc.). Charged- and uncharged-spray treatments, which consisted of 28-s-duration 100-mL sprays from a set of three air-atomizing induction-charging nozzles, were applied to a conductive mannequin and to a human subject. Mass transfer was determined for each treatment by recovering fluorescent tracer-laden spray from stainless-steel discs strategically placed on the target mannequin and human subject. The charged-spray treatments (-13 mC/kg charge-to-mass, 30 /spl mu/m volume-median diameter) resulted in whole-body-averaged mass transfer of typically twofold-greater deposition than treatments of uncharged spray. Similar electrodeposition responses were seen between grounded human and mannequin subjects. Voltage rise and decay of an ungrounded capacitively coupled human subject undergoing two 14-s charged-spray treatments were measured to determine whether or not human subjects must be directly grounded. Resistive paths from the target body to earth in the spray chamber's high-humidity environment were sufficient to prevent significant charge accumulation on the subject. Concentrations of unwanted respirable airborne mists within the chamber were monitored during and after charged- and uncharged-spray treatments. The respirable mist concentration during charged-spray treatments peaked at 40 mg/m/sup 3/ while uncharged mist peaked at over 150 mg/m/sup 3/.