Functional geraniol-Ca(OH)₂ composite/sodium acetate alginate film on nonwoven polyethylene sheet: acetic acid gas production in response to acid

An alginate film, which released geraniol under ordinary conditions and produced acetic acid gas in response to acid, was directly prepared on a polyethylene nonwoven sheet. This alginate film was composed of geraniol-calcium hydroxide [Ca(OH)₂] composite, which was prepared by mixing geraniol and calcium oxide (CaO), and sodium alginate solution (Na-Alg) containing sodium acetic acid (CH₃COONa). Geraniol release from the alginate film could be monitored over time. Optimal conditions for the alginate film preparation were 0.75 or 1.0% Na-Alg solution containing 10% (w/v) CH₃COONa. Acetic acid (~3.58 ppm) could be generated from the sheet under these conditions by dropping 1.0 M hydrochloric acid (0.3 mL) onto it. We successfully prepared a functional sheet, which changed its released odor from geraniol to acetic acid gas in response to acid.