A membrane workshop run by Hochi Technology in Hai'an, Nantong, Jiangsu. [Photo/Nantong Daily]

From smart dimming films in new energy vehicles to touch films in smartphones and self-healing films in furniture, functional membrane materials have become indispensable to modern industry.

Hai'an, Jiangsu, is fast becoming a national leader in this field, with over 90 enterprises in the membrane materials supply chain and sales reaching 10.2 billion yuan ($1.42 billion) in 2024, up 12 percent year-on-year.

At Jiangsu Dongcai New Materials, optical-grade polyester base films are produced on smart lines with a monthly capacity of 15 million square meters. "Our base films are essential to polarizers, a core component of new display technologies," said general manager Cheng Fanbao.

With a 700-member team including polymer specialists, Dongcai has achieved world-class standards in cleanliness and smoothness, fueling its rise from 400 million yuan in sales in 2017 to over 2 billion yuan today.

Hochi Technology has also thrived in Hai'an since 2013. Specializing in automotive films, the company supplies leading automakers like BYD, Nissan, and GM, and exports globally. Hochi's success is supported by local government-backed collaborations with top institutions such as Tsinghua and the Chinese Academy of Sciences.

Meanwhile, the Nanjing University Hai'an High-Tech Research Institute drives innovation, including a breakthrough cooling film for solar panels. The institute also serves as the secretariat for the newly approved Jiangsu Functional Membrane Materials Standards Committee, marking Hai'an's shift from industry participant to standards leader in China's membrane sector.