According to data from Tianyancha, on March 18, 2025, Guangzhou Aosong Electronics Co., Ltd. was awarded an invention patent by the National Intellectual Property Administration. The patent, named 'Copolymer Comprising PVDF Units, Its Preparation Process, Humidity-Sensitive Film, and Uses Thereof', bears the authorization announcement number CN115894804B. The application for this patent was filed on October 26, 2022.

The crux of this invention lies in the following process: Initially, PVDF is subjected to an alkali treatment to introduce unsaturated bonds, resulting in a modified PVDF. Subsequently, this modified PVDF undergoes free radical polymerization with aromatic vinyl monomers, silicon-containing comonomers, and initiators in a precise mass ratio of (10–20):(5–10):(2–4):(0.1–1). This reaction yields a copolymer that boasts exceptional mechanical properties and hydrolytic stability.

To transform this copolymer into a humidity-sensitive film, it is coated and then subjected to a programmed temperature elevation process, specifically: from room temperature to 80℃ over 1 hour, then to 120℃ over another hour, and finally to 150℃ over an additional hour. The end result is a humidity-sensitive film with a thickness ranging from 3 to 5 micrometers. When utilized in humidity sensors, this film exhibits remarkable measurement accuracy and outstanding linearity.