Fabrication of PVA Hydrogel Coated 3D Printed PETG Optical Fiber for Biocompatible Biomedical Applications

Dip coating is widely used in hydrogel based optical fiber. However, obtaining a uniform coating for microstructure such as optical fiber remains a challenge where its influence on the optical output is still scarce in literature. Dip coating parameters such as speed and viscosity of the solution will affect both the uniformity and thickness of the coating. Therefore, this study aims to investigate the optical output of optical fiber core coated with Polyvinyl Alcohol (PV A) hydrogel with varied dip coating speed (15, 30, 45, 60, 75 and 90 mm/min) and PVA concentrations (10, 15 and 20%). Firstly, the core of the optical fiber was self-fabricated using 3D printing technology, directly extruded from the commercially available Polyethylene Terephthalate Glycol-modified (PETG) filament. The uniformity and thickness of the coating were observed under optical microscope follows by analyses in ImageJ software to measure the thickness at four different points (top, bottom, left and right). The optical output is measured using 650 nm light source and measured using optical power meter. The results revealed that the higher the concentrations with high speed will results in a thicker coating compared with employing low concentrations at high speed. However, regardless of the speed and concentrations, all the coatings show non-concentricity which influence the optical output intensity. Optical power output shows that the higher optical output can be observed at high concentrations of 20% as it led to thicker coating regardless of the different speeds compared 10% PVA concentrations. Despite the non-uniform coating, the optical output of all the coated fiber shows improvement compared to non-coated fiber