Effects of silicon doping on strengthening adhesion at the interface of the hydroxyapatite–titanium biocomposite

A first-principles study

Research output: Contribution to journalArticle

Abstract

In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to −2.52 J m−2, which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti–O and three Ca–O bonds are formed for a-Si-HAP/a-TiO2 and one Ti–O and three Ca–O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25% higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials.

Original languageEnglish
Pages (from-to)228-234
Number of pages7
JournalComputational Materials Science
Volume159
DOIs
Publication statusPublished - 1 Mar 2019

Fingerprint

calcium phosphates
Strengthening (metal)
Silicon
First-principles
Strengthening
Adhesion
TiO2
Calcium phosphate
Calcium
Phosphate
adhesion
Doping (additives)
silicon
Atoms
Charge density
Charge
atoms
Coating
P-atom
Phosphate coatings

Keywords

  • Biomaterials
  • Computer simulations
  • Density functional theory (DFT)
  • Hydroxyapatite-coated titanium
  • Interface
  • Tensile testing

ASJC Scopus subject areas

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

Cite this

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title = "Effects of silicon doping on strengthening adhesion at the interface of the hydroxyapatite–titanium biocomposite: A first-principles study",
abstract = "In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to −2.52 J m−2, which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti–O and three Ca–O bonds are formed for a-Si-HAP/a-TiO2 and one Ti–O and three Ca–O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25{\%} higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials.",
keywords = "Biomaterials, Computer simulations, Density functional theory (DFT), Hydroxyapatite-coated titanium, Interface, Tensile testing",
author = "Grubova, {Irina Yu} and Surmeneva, {Maria A.} and Stijn Huygh and Surmenev, {Roman A.} and Neyts, {Erik C.}",
year = "2019",
month = "3",
day = "1",
doi = "10.1016/j.commatsci.2018.12.026",
language = "English",
volume = "159",
pages = "228--234",
journal = "Computational Materials Science",
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TY - JOUR

T1 - Effects of silicon doping on strengthening adhesion at the interface of the hydroxyapatite–titanium biocomposite

T2 - A first-principles study

AU - Grubova, Irina Yu

AU - Surmeneva, Maria A.

AU - Huygh, Stijn

AU - Surmenev, Roman A.

AU - Neyts, Erik C.

PY - 2019/3/1

Y1 - 2019/3/1

N2 - In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to −2.52 J m−2, which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti–O and three Ca–O bonds are formed for a-Si-HAP/a-TiO2 and one Ti–O and three Ca–O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25% higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials.

AB - In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to −2.52 J m−2, which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti–O and three Ca–O bonds are formed for a-Si-HAP/a-TiO2 and one Ti–O and three Ca–O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25% higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials.

KW - Biomaterials

KW - Computer simulations

KW - Density functional theory (DFT)

KW - Hydroxyapatite-coated titanium

KW - Interface

KW - Tensile testing

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U2 - 10.1016/j.commatsci.2018.12.026

DO - 10.1016/j.commatsci.2018.12.026

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EP - 234

JO - Computational Materials Science

JF - Computational Materials Science

SN - 0927-0256

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