The NTU team creates pollen-based paper that folds itself into boxes, straws, environmental news and featured articles

SINGAPORE – New light brown paper made of sunflower pollen can automatically fold into a food container or straw when exposed to air humidity, breaking the mold for single-use packaging.

Smart Pollen Paper – created by scientists at Nanyang Technological University (NTU) – is created by adding potassium hydroxide to sunflower pollen grains.

After 24 hours, the pollen turns into a gel that is molded, for example, on a Petri dish and left to dry overnight. The dried pollen paper is then peeled from the mold.

Pollen paper can vary in thickness from 20 to 200 microns, similar to that of a strand of hair – but it is far from fragile.

In fact, pollen is known as the diamond of the plant kingdom because it is one of nature’s most enduring materials, said research team co-lead Professor Cho Nam-Joon of NTU’s School of Materials Science and Engineering.

Professor Cho’s research includes turning pollen into alternatives to plastic and metal.

Pollen paper can be thickened or layered if it needed to be folded into a container or straw. It can be used as a greener alternative to materials such as plastics and styrofoam for disposable products and packaging.

Pollen is also abundant and can degrade gradually in nature.

“If we make the paper thicker, its properties will be closer to plastic. The original raw material itself is very strong. So by changing that, it can be stronger,” said Prof Cho.

Pollen paper comes alive when exposed to moisture, and after a little bit of toner – a powder that works like printer ink – prints lines and patterns on the brown paper. Toner acts like ink in office and home laser printers.

To apply toner to pollen paper, it goes through an ordinary printer, just like writing paper.

The pollen paper is then exposed to different levels of humidity in a controlled environment.

While pollen paper is sensitive to moisture in the air and curls, the inked parts do not react to water. These opposing behaviors cause flat paper to transform into three-dimensional shapes when humidity decreases.

How the paper folds or twists depends on the printed pattern.

For example, a piece of pollen paper cut from the outline of a box would automatically fold into a box when the folded hinges are printed with vertical barcode-like lines.

A strip of paper printed with diagonal lines would wind up into a straw.

Prof Cho said, “The products can be made without manual bending, reducing the skills and time required for manufacturing. The whole process is also environmentally friendly and scalable.”

Coating the processed paper with petroleum jelly or chitosan – a natural sugar found in the shells of crabs and crustaceans – will prevent the product from falling apart due to changes in humidity and keep it in shape.

NTU President Subra Suresh, who co-led the research, said, “We have combined easy-to-process pollen grains and cost-effective digital printing to develop a moisture-sensitive (material) that can transform. on demand in … complex shapes. according to the designs we print. “

Prof Cho said it was the first time pollen has been used to develop self-folding materials. The research team’s method was published in the scientific journal Proceedings Of The National Academy of Sciences of the United States of America last month.

Packaging waste, including plastics, accounts for about a third of household waste in Singapore. Last year, around 200,000 tonnes of disposables – including carry bags and take-out containers – were thrown here.

The NTU team is now working on optimizing its paper and method for pollen so that companies can eventually use the technology to make greener products, including moisture sensors.