JOURNAL OF COSMETIC SCIENCE 208 Observation of the behavior of Formulation A demonstrated that this system did not leave any noticeable residue on the stratum corneum. The corneocytes appear very dis- tinct and no apparent fi lm was deposited on its surface. Such results are expected as For- mulation A contains about 93% (w/w) alcohol, which most likely evaporated before obtaining the micrographs. On the other hand, for Formulation B, which contained the polymeric fi lm former VA/butyl maleate/isobornyl acrylate copolymer at a level of 1% (w/w), we observed that the polymer formed a network over the stratum corneum. The network appeared a bit darker in the image than the corneocyte background. One interesting aspect of this fi lm former is its ability to form a clear, interconnected network over the stratum corneum as opposed to a distinct spray particle deposited on the surface. F igure 2. SEM micrographs of various sun care formulations deposited (sprayed) onto layers of stratum corne- um cells (magnifi cation = ×300). (A) Formulation A, (B) Formulation B, (C) Formulation C, (D) Formulation D, (E) Formulation E, and (F) Formulation F.

FILM PROPERTIES OF POLYMERS USED IN ANHYDROUS SUNSCREEN FORMULATIONS 209 Formulation C, which contained a sunscreen phase, but no polymer, appears to have cov- ered the entire surface of the corneocytes with a sunscreen fi lm. The fi lm entirely covered the surface, as evident in the SEM micrographs. The individual corneocytes were less apparent as the fi lm entirely covered the surface. There are many similarities between Fig ure 3. SEM micrographs of various sun care formulations deposited (sprayed) onto layers of stratum corneum cells (magnifi cation = 500–×1,000). (A) Formulation A, (B) Formulation B, (C) Formulation C, (D) Formulation D, (E) Formulation E, and (F) Formulation F.