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

3Figure 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

1020304050607080

Samples stored in glass Petri-dish in air

Day 0Day 1Day 2Day 3Day 4Day 5Day 8Day 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, 34d

419

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)

Wat

er C

onta

ct A

ngle

(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)

Wat

er C

onta

ct A

ngle

(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)

Wat

er C

onta

ct A

ngle

(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?