Replication and Tribological Engineering of Physical Surfaces Using Two-Photon Lithography

Student: Shelby Maddox

Degree: Ph.D., August 2020

Major Professor: Dr. Min Zou

Research Area(s):

Conventional Materials & Processes

Nanoscience & Engineering

View Research Quadslide


  • Nearly 10% of all automotive energy waste comes from the interface between the piston compression ring and the cylinder liner
  • The liner itself is modified in situ by the action of the piston: this “run-in” time wastes energy
  • Inspiration from nature can improve this and many other types of friction-bearing surfaces


  • Use the mutated PFTs in experiments to determine the voltage at which they gate and compare it to wild type PFTs.
  • Process to “copy” and print physical 3D structures
  • Digitized surfaces can be modified to include other textures
  • Hierarchical textures can be combined with biomimetic designs


Optical laser microscopy to analyze the surfaces

  • High resolution (sub-micron) heightmaps are obtained and analyzed for roughness parameters
  • Heightmap data is processed to create 3D printable files

Two-photon lithography to create physical structures

  • Printing process allows quick turnaround of testing and development cycle
  • Etching masks will also be developed, for use with a novel process to print masks directly onto curved surfaces (ring segments)

Key Results

  • Process for transforming scan data into high-resolution 3D print files
  • “Xeroxing” of existing physical structures

Potential Applications

  • Quick testing cycle of parameter-modified surfaces before robust, complex fabrication
  • Broadly applicable for copying any surface, such as biotribologically inspired surfaces

Future/Ongoing Work

  • The scanned data can be modified to improve the mechanical performance of the liner texture
  • Many bioinspired designs can be studied