Subtractive 3D printing using cellulose

Cellulose, one of the most abundant biological materials on earth, is an organic compound made up of glucose polymers. Its comprising macromolecules assemble into complex supramolecular structures, providing exceptional mechanical strength and unique optical properties.

Due to its biodegradable but water insoluble nature, cellulose is being investigated as an organic structural material.

Mironov et al. have developed an approach to microfabrication using cellulose-derived polymers, in which incoherent light is used to locally remove organic materials with high precision.

The process uses photoablative lithography with cellulose acetate and cellulose acetate butyrate to pattern complex 3D micro and nanostructures through subtraction. The procedure is simple, fast, and inexpensive, capable of fabricating intricate optical components and microfluidic devices.

“Currently, the fabrication of micrometer-scale components and subsystems requires expensive processing equipment, a clean room environment and generally, processing in a vacuum,” said author Andrey Mironov. “The processes we have described will enable multiple institutions – universities, research laboratories and manufacturers – to fabricate microstructures in a short time and without toxic chemicals.”

Short wavelength light sources were utilized to non-thermally and precisely etch materials by breaking specific chemical bonds in the material. Devices manufactured by this process could be used in medical applications, sensors, and optical devices.

“We expect that, when optimized, the reported technique will allow eco-friendly, large scale and low-cost manufacturing of recyclable, microfluidic devices for express bioanalysis,” said Mironov. “The photoprocesses are also well suited for producing lightweight but complex optical components for cell phones and communication systems.”

Source: “Photoablative lithography of cellulose acetate at 172 nm: Subtractive 3D printing of biodegradable optical microstructures and molds for polydimethylsiloxane patterning,” by Andrey E. Mironov, Sehyun Park, Jinhong Kim, Dane J. Sievers, Sung-Jin Park, Stephan Spirk, and J. Gary Eden. APL Materials (2021). The article can be accessed at https://doi.org/10.1063/5.0065511 .