Effect of Storage Temperature on Ti-6Al-4V Surface Wettability

Caio Peixoto*, Arman Butt** and Christos Takoudis**

*Federal University of Rio Grande do Norte

**University of Illinois at Chicago

Outline

• Motivation and Background

• Sample Preparation

• Surface Characterization

– Roughness (Zygo)

– Chemistry (Fourier Transform Infrared Spectroscopy – FTIR)

– Wettability (Water Contact Angle)

• Conclusions

22

Motivation and Background

Titanium and Alloys

• Corrosion resistance, mechanical properties and biocompatibility

• Numerous biomedical applications– Dentistry– Orthopaedics– Cardiovascular– Ophthalmology

2Figure from Geetha Manivasagam et al. Biomedical Implants: Corrosion and its Prevention - A Review. Recent Patents on Corrosion Science. 2010, pp. 40-54. 3

Osseointegration

• Connection between the implant and the living bone• Prevention of implant loosening

3Figure adapted from M. Geetha et al. Ti based biomaterials, the ultimate choice for orthopaedic implants - A review. Pregress in Materials Science. 2009, pp. 397-425. 4

Water adsorption Proteins adsorption Cells adsorption

Water Dissociation on TiO2 Surface

3

Figure adapted from Z. Zhang et al. Imaging Water Dissociation on TiO2(110): Evidence for Inequivalent Geminate OH Groups J. Phys. Chem. B 2006, 110, 21840-21845 5

(a) TiO2 surface with oxygen vacancy

(b) Two hydroxyl groups HV (at a vacancy) and HB (protonation of neighbor oxygen atom) formed by water adsorption and dissociation

(c) HB diffusion

Motivation

• Current storage method: samples in air (Petri-dish or Kimwipe

• Decrease in wettability over time• Materials can be mistakenly classified as bad by further

tests

6

200 °C 400 °C 600 °C0

10

20

30

40

50

60

70

80

Samples stored in glass Petri-dish in air

Day 0

Day 1

Day 2

Day 3

Day 4

Day 5

Day 8

Day 9

Thermally oxidized samples

Ave

rage

Wat

er C

onta

ct A

ngle

(°)

Evolution of water contact angle – Samples stored in glass petri –dish in air (Data acquisition and graph preparation by

Sweetu Patel)

6

Samples in current storage conditions

Background

• Surface wettability decreases over time due to poor

storage methods1

• At 2x10-10 Torr, increase in temperature results in water

desorption and hydroxyl group loss2

7

[1] Jung Hwa Park et al. Effect of cleaning and sterilization on titanium implant surface properties and cellular response. Acta Biomaterialia, 2011

[2] Amy L. Linsebigler, et al. Photocatalysis on TiOn Surfaces: Principles, Mechanisms, and Selected Results . Chem. Rev. 1995, 95, 735-758. 7

Sample Preparation

Sample Preparation

• Sandblasting – 50 µm alumina grit particles– 517 kPa

28

• Acid Etching

Figure from L.G. Harris, et al.Staphylococcus aureus adhesion to titanium oxide surfaces coated with non-functionalized and peptide-functionalized poly(l-lysine)-grafted-poly(ethylene glycol) copolymers, Biomaterials, Volume 25, Issue 18, August 2004

H2SO4 + H2O2 → H2SO5 + H2O

Sample Preparation

• Sonication – 1 hour methanol (99.8%)

• Wash – 30 seconds deionized water (DI-water)

• Annealing – 3h in air

29

AnnealingScheme (adapted from http://www.memsnet.org/mems/processes/deposition.html)

Not Annealed

400 ºC

600 ºC

Annealing Storage Condition

Group 1

Not Annealed

Kimwipe

Group 2 Room Temp. DI-Water

Group 3 Cold DI-Water*

Group 4

400 ºC

Kimwipe

Group 5 Room Temp. DI-Water

Group 6 Cold DI-Water*

Group 7

600 ºC

Kimwipe

Group 8 Room Temp. DI-Water

Group 9 Cold DI-Water*

10*Refrigerator temperature: 8 ± 2 ºC

Surface Characterization

Zygo

411

Roughness (µm)

Not Annealed 400 ºC 600 ºC

RMS 2.27 ± 0.27 2.57 ± 0.47 2.51 ± 0.56

Sample 45 surface

FTIR

412

• Infrared Spectrum (absorbance)

• Deconvolution using XPSpeak

Figure from http://www.bgtu.net/image/ik.jpg

13

14

15

Anatase

Ti-O bond

16

17

RutileV-O

Al2O3

18

Al2O3

Water Contact Angle

• Water contact angle measurements

– After 0h, 3h, 6h,12h, 1d, 2d, 6d, 9d,13d, 16d and 20d

• Cold water groups let to warm up to room temperature

– Measurements after 20d3h, 20d6h, 20d12h, 21d, 23d and

27d

• Warm up all the samples to 37 °C

– Measurements after 27d3h, 27d6h, 27d12h, 28d, 30d, 34d419

20

0 5 10 15 20 25 30 350

20

40

60

80

100

120

140

160

Samples Not AnnealedGroups 1, 2 and 3

Kimwipe Room Temperature Water Cold Water

Time (days)

Wa

ter

Co

nta

ct

An

gle

(º)

Cold water samples warmed up to room temperature

Samples immersed in water and warmed up to 37 ºC

21

0 5 10 15 20 25 30 350

20

40

60

80

100

120

140

160

Samples Annealed at 400 ºCGroups 4, 5 and 6

Kimwipe Room Temperature Water Cold Water

Time (Days)

Wa

ter

Co

nta

ct

An

gle

(º)

Cold water samples warmed up to room temperature

Samples immersed in water and warmed up to 37 ºC

22

0 5 10 15 20 25 30 350

20

40

60

80

100

120

140

160

Samples Annealed at 600 ºCGroups 7, 8 and 9

Kimwipe Room Temperature Water Cold Water

Time (Days)

Wa

ter

Co

nta

ct

An

gle

(º)

Cold water samples warmed up to room temperature

Samples immersed in water and warmed up to 37 ºC

23

Conclusions

• Best annealing temperature: 600 ºC– Rutile formation– Signatures related to vanadium and aluminum oxides from FTIR

spectrum

Water Contact Angle After 34 Days (º)

  Not Annealed 400 ºC 600 ºC

Kimwipe 61 ± 10 54 ± 10 31 ± 13

Room Temperature Water 12 ± 4 12 ± 4 7 ± 2

Cold Water 9 ± 3 12 ± 4 4 ± 2

24

Conclusions

• Best storage condition: immersed in DI-water– Storage temperature showed no major effect– Samples wrapped in Kimwipe decreased drastically when

immersed in DI-water– Water dissociation reaches equilibrium

Figure adapted from Z. Zhang et al. Imaging Water Dissociation on TiO2(110): Evidence for Inequivalent Geminate OH Groups J. Phys. Chem. B 2006, 110, 21840-21845

Acknowledgments

AMReLAdvanced Materials Research Laboratory

ORTHOPAEDIC AND DENTAL RESEARCH GROUP

RUSH, Michigan Tech and UIC

Dr. Gregory Jursich, Sweetu Patel, Azhang Hamlekhan and Dmitry Royhman

Questions? Comments?