Advanced Paper Could Be the Foundation For Inexpensive Biomedical and Diagnostic Devices

The modified paper could be used as the foundation for a new generation of inexpensive biomedical diagnostics

Paper is known for its ability to absorb liquids, making it ideal for products such as paper towels. But by modifying the underlying network of cellulose fibers, etching off surface “fluff” and applying a thin chemical coating, researchers have created a new type of paper that repels a wide variety of liquids – including water and oil.

The paper takes advantage of the so-called “lotus effect” – used by leaves of the lotus plant – to repel liquids through the creation of surface patterns at two different size scales and the application of a chemical coating. The material, developed at the Georgia Institute of Technology, uses nanometer- and micron-scale structures, plus a surface fluorocarbon, to turn old-fashioned paper into an advanced material.

The modified paper could be used as the foundation for a new generation of inexpensive biomedical diagnostics in which liquid samples would flow along patterns printed on the paper using special hydrophobic ink and an ordinary desktop printer. This paper could also provide an improved packaging material that would be less expensive than other oil- and water-repelling materials, while being both recyclable and sustainable.

“Paper is a very heterogeneous material composed of fibers with different sizes, different lengths and a non-circular cross-section,” said Dennis Hess, a professor in the Georgia Tech School of Chemical and Biomolecular Engineering. “We believe this is the first time that a superamphiphobic surface – one that repels all fluids – has been created on a flexible, traditional and heterogeneous material like paper.”

Research leading to development of the superamphiphobic paper has been supported by the Institute for Paper Science and Technology (IPST) at Georgia Tech. Details were published online May 24 in the journal ACS Applied Materials & Interfaces.

The new paper, which is both superhydrophobic (water-repelling) and super oleophobic (oil-repelling), can be made from standard softwood and hardwood fibers using a modified paper process. In addition to Hess, the research team included Lester Li, a graduate research assistant, and Victor Breedveld, an associate professor in the School of Chemical and Biomolecular Engineering

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