193 nm ArF laser ablation and patterning of chitosan thin films

• Published in: Applied physics. A, Materials science & processing Vol. 124; no. 6; pp. 1 - 10
• Main Authors: Aesa, A. A., Walton, C. D.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2018; Springer Nature B.V
• Subjects: Applied physics; Biopolymers; Characterization and Evaluation of Materials; Chitosan; COLA2017; Condensed Matter Physics; Finite element method; Gravimetric analysis; Laser ablation; Lasers; Machines; Manufacturing; Materials science; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Scanning electron microscopy; Spin coating; Surfaces and Interfaces; Thin Films; White light interferometry
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-018-1859-z

This paper reports laser ablation studies on spin-coated biopolymer chitosan films, β-l,4-1inked 2-amino-2-deoxy- d -glucopyranose. Chitosan has been irradiated using an ArF laser emitting at 193 nm. An ablation threshold of F T  = 85±8 mJ cm −2 has been determined from etch rate measurements. Laser-ablated chitosan is characterised using white light interferometry, scanning electron microscopy, and thermo-gravimetric analysis. Laser ablation of chitosan is discussed in terms of thermal and photoacoustic mechanisms. Heat transfer is simulated to assist in the understanding of laser-irradiated chitosan using a finite-element method and the software package COMSOL Multi-Physics™. As a demonstrator, a micro-array of square structures in the form of a crossed grating has been fabricated by laser ablation using a mask projection scanning method. The initial investigations show no evidence of thermal damage occurring to the adjacent chitosan when operating at a moderately low laser fluence of 110 mJ cm −2 .