At 9:00 AM on Monday, August 12, 2024, a discussion of the master's thesis in the Department of Laser Engineering and Optical Electronics / College of Engineering / Al-Nahrain University was held in the department's hall. The thesis, presented by Sarah Sabah, was titled:

'Generation of Nanostructures on Material Surfaces Using Lasers and Their Application in the Field of Biological Sensors'.

ABSTRACT

This work created (LIPSS) laser-induced periodic surface structures by laser ablation of stainless steel. A YAG fibre laser with a frequency of 1064 nm was employed. 304L stainless steel samples were exposed to radiation at a frequency of (20–80) kHz, with a power of 104 w and a pulse duration of 81 ns. Laser radiation causes periodic surface structures of morphological grooves to be generated on the surface of 304L stainless steel. These patterns are referred to as laser-induced continuous surface structures. The morphology and surface topography of 304L stainless steel were analyzed using SEM and AFM, respectively. The findings demonstrated a direct relationship between surface roughness and the power, speed, and spot size employed.

When a surface can repel water droplets, it is said to have a superhydrophobic property. To be posses as a super-hydrophobic surface, the surface must possess a high apparent contact angle (more than 1500), a low contact angle hysteresis (less than 100), a low sliding angle (less than 50), and excellent Cassie model state stability. Super hydrophilic surface obtained at P = 3mw, ω = 10 μm and v = 6000 mm/s were the ones that achieved the highest roughness the lowest roughness was obtained at P= 1 mw, ω=100 μm, and v=3250mm/s, and after examining the contact angle with the water drop, it was found that this surface is hydrophobic.

The discussion committee consisted of:

Assist. Prof. Ahmed Riyad / Al-Nahrain University / Chair

Assist. Prof. Sarah Kazem / University of Baghdad / Member

Dr. Wurood Abdulkhaleq / Al-Nahrain University / Member

Dr. Rana Muhammad / Al-Nahrain University / Supervisor

The student received a grade of 'Very Good'.