"Invisible" Digital Light Processing 3D Printing with Near Infrared Light
Lynn M Stevens1, Clotilde Tagnon1, Zachariah A Page1
1Department of Chemistry, The University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, Texas 78712, United States.
ACS Applied Materials & Interfaces
|January 26, 2022
Summary
Researchers developed a novel 3D printing method using low-intensity, near-infrared (NIR) light. This breakthrough enables printing with new materials, including biological components and nanoparticles, overcoming limitations of traditional ultraviolet light 3D printing.
Area of Science:
- Materials Science
- Photochemistry
- Additive Manufacturing
Background:
- Traditional ultraviolet (UV) light 3D printing is limited by material absorption, scattering, and degradation.
- Existing methods struggle to match UV light's speed and resolution when using longer wavelengths.
- Recent advances have enabled printing with orange/red light, but challenges remain for longer wavelengths.
Purpose of the Study:
- To demonstrate a photosystem for low-intensity, long-wavelength (near-infrared, NIR) light-driven 3D printing.
- To overcome the speed and resolution limitations of current long-wavelength printing techniques.
- To enable 3D printing with a broader range of materials, including biological components and nanoparticles.
Main Methods:
- Developed a photosystem combining a NIR-absorbing cyanine dye with redox pairs for catalytic photocuring.
- Utilized in situ spectroscopic and rheological monitoring to characterize polymerization rates and solidification times.
- Optimized resin composition and printing parameters for NIR digital light processing (DLP) 3D printing.
- Demonstrated composite 3D printing with nanoparticle-infused resins.
Main Results:
- Achieved rapid photocuring using low-intensity (<5 mW/cm²) NIR light (∼850 nm).
- Enabled projection-based 3D printing with speeds under 60 seconds per layer and feature resolution under 300 μm.
- Successfully performed composite 3D printing with nanoparticle-infused resins.
- Observed improved feature fidelity in NIR-printed structures compared to UV-printed ones.
Conclusions:
- The developed NIR photosystem facilitates low-intensity, long-wavelength 3D printing, expanding material possibilities.
- This technology overcomes limitations of UV-based printing, enabling the inclusion of sensitive components like nanoparticles and biomaterials.
- The findings provide insights for next-generation wavelength-selective, multi-material 3D bio- and composite-printing.
