Hydroxyapatite-Based Coatings on Silicon Wafers and Printed Zirconia

Authors

Antoine Chauvin, University of Nebraska-LincolnFollow

First Advisor

Li Tan

Second Advisor

Nicolas Delpouve

Date of this Version

11-2023

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Mechanical Engineering of Mechanical Science

Under the supervision of Professor Li Tan

Lincoln, Nebraska, November 2023

Comments

Copyright 2023, Antoine Chauvin

Abstract

Dental surgery needs a naturally attract implant design that can ensure both osseointegration and soft tissue integration. Hydroxyapatite (HAp), the main mineral constituent of dentine and tooth enamel, is commonly used as a coating component, notably for overlaying titanium– or ceramics–based implants. This thesis aims to investigate the behavior of a HAp-based coating, specifically designed to be compatible with a porous substrate. Coating layers are made by sol–gel dip coating by immersion of porous substrates made by additive manufacturing into solutions of HAp, having been mixed with polyethyleneimine (PEI), to improve the adhesion of HAp on the substrate. First, the layer is deposited on silicon wafers that are annealed after immersion to obtain a homogenous crystalline phase. The microstructure is determined from X–ray diffraction (XRD) to assess the adhesion of HAp, whereas the topography is examined from atomic force microscopy (AFM) to evaluate the homogeneity of the coating repartition. Possible traces of PEI consecutive to the annealing are searched by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier–transform infrared spectroscopy (FTIR), without revealing the residual presence of polymer. Finally, the scanning electron microscopy (SEM) pictures taken on printed zirconia ceramics designed by the digital light processing (DLP) additive manufacturing method, reveal that the mixed coating leads to obtaining, after annealing, a thicker and more uniform layer in comparison with pure HAp coating. Thus, it is assumed that the blend adheres better to the porous surface obtained by the DLP technique. Therefore, this coating design, based on additive manufacturing, could reveal some potential as a low–cost alternative for dentistry applications.

Advisor: Li Tan