Development of Nanofluidic Development of Nanofluidic Cells for Ultrafast X rays Cells for Ultrafast X rays

Studies of WaterStudies of Water

Melvin E. Irizarry-GelpíMelvin E. Irizarry-Gelpí

Aaron LindenbergAaron Lindenberg

Brief OutlineBrief Outline

BackgroundBackground Water and its structureWater and its structure ExperimentsExperiments Confined liquidsConfined liquids

Nanofluidic cellsNanofluidic cells The apparatusThe apparatus Sample CharacterizationSample Characterization ResultsResults

WaterWater

Ice structure Liquid water

•Liquid water exhibits structural rearrangements on picosecond and femtosecond time-scales

•How does the structure and dynamics of liquids confined to nanoscopic length-scales differ from the bulk?

Femtosecond x-ray absorption Femtosecond x-ray absorption spectroscopyspectroscopy

Use femtosecond laser to drive hydrogen bond Use femtosecond laser to drive hydrogen bond networknetwork

Ultrafast soft x-ray pulses provide the necessary Ultrafast soft x-ray pulses provide the necessary resolution to probe bonding dynamicsresolution to probe bonding dynamics

In order to perform measurements, nanofluidic In order to perform measurements, nanofluidic cells (<500 nm thickness) are requiredcells (<500 nm thickness) are required

Previous MethodsPrevious Methods

Nanofluidic CellsNanofluidic Cells

Two SiTwo Si33NN44 1 mm x 1 1 mm x 1 mm and 0.5 mm x 0.5 mm and 0.5 mm x 0.5 mm windowsmm windows

Thickness < 500 nmThickness < 500 nm Photoresist spacer Photoresist spacer

and Polystyrene and Polystyrene nanospheres with nanospheres with different diameters different diameters (200 nm and 500 nm)(200 nm and 500 nm)

http://www.silson.com/pics/standard10.jpg

window

water layer

windowspacer

The SIMPLEtronThe SIMPLEtron

Simple and Simple and reproducible way to reproducible way to make cellsmake cells

Micrometer stages Micrometer stages allow for accurate allow for accurate position of sample position of sample cells and application cells and application of nanoliter quantities of nanoliter quantities of waterof water

Sample preparation Sample preparation takes minutestakes minutes

Sample holderSample holder

Sample characterizationSample characterization

FTIR at SU

XAS at beamline 6.3.2 ALS - LBNL

Results (FTIR)Results (FTIR)

0 500 1000 1500 2000 2500 3000 3500 4000 4500-0.2

0

0.2

0.4

0.6

0.8

1

1.2

Wavenumber (cm-1)

Abs

orba

nce

pwater19 & Bertie data (thickness = 500 nm, volume = 2000 nL)

BertieUs

http://www.lsbu.ac.uk/water/vibrat.html#d

Peaks related to vibrational modes

Results (XAS)Results (XAS)

510 520 530 540 550 560 570 5800.93

0.94

0.95

0.96

0.97

0.98

0.99

1

1.01

Energy (eV)

Tra

nsm

issi

on

Sample water000043, thickness = 25 nm (from CXRO - LBNL)

Thickness (FTIR)Thickness (FTIR)

Plain waterPlain water Polystyrene spheresPolystyrene spheres

1000 nm1000 nm 1010 nm1010 nm

450 nm450 nm 520 nm520 nm

220 nm220 nm 1750 nm1750 nm

145 nm145 nm 1500 nm1500 nm

150 nm150 nm 500 nm500 nm

1800 nm1800 nm

Thickness (XAS)Thickness (XAS)

Plain waterPlain water Polystyrene spheresPolystyrene spheres

15 nm15 nm 1 nm1 nm

5 nm5 nm 10 nm10 nm

15 nm15 nm 17 nm17 nm

25 nm25 nm

Preliminary observation of Preliminary observation of confinement effectsconfinement effects

Observe shift in main Observe shift in main absorption peak to absorption peak to lower energy as lower energy as sample thickness sample thickness decreasesdecreases

Indication of change Indication of change in structure (to a more in structure (to a more ice-like configuration) ice-like configuration) for ultrathin samplesfor ultrathin samples

Confined LiquidsConfined Liquids

ConclusionsConclusions

A simple and reliable means of producing A simple and reliable means of producing nanofluidic water cells has been developednanofluidic water cells has been developed

A range of thickness may be produced, although A range of thickness may be produced, although randomrandom

Evidence for changes in the x-ray absorption Evidence for changes in the x-ray absorption spectrum for ultrathin samples is observedspectrum for ultrathin samples is observed

Future experiments will couple a femtosecond Future experiments will couple a femtosecond laser into the sample to probe the structural laser into the sample to probe the structural dynamics of water on ultrafast time-scalesdynamics of water on ultrafast time-scales

AcknowledgementsAcknowledgements

U. S. Department of Energy, Office of U. S. Department of Energy, Office of Science, SULI ProgramScience, SULI Program

SLAC and Stanford UniversitySLAC and Stanford University Advance Light Source at Lawrence Advance Light Source at Lawrence

Berkeley National LaboratoryBerkeley National Laboratory Special thanks to Aaron LindenbergSpecial thanks to Aaron Lindenberg

Thank you for your Thank you for your attentionattention

QuestionsQuestions

ReferencesReferences

[1] L. N¨aslund, “Probing unoccupied electronic states in aqueous [1] L. N¨aslund, “Probing unoccupied electronic states in aqueous solutions,” Ph.D. dissertation, Stockholm University, Stockholm, solutions,” Ph.D. dissertation, Stockholm University, Stockholm, 2004. [Online]. Available: http://urn.kb.se/resolve?2004. [Online]. Available: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-294urn=urn:nbn:se:su:diva-294

[2] J. E. Bertie and Z. Lan, [2] J. E. Bertie and Z. Lan, Applied SpectroscopyApplied Spectroscopy, vol. 50,no. 8, pp. , vol. 50,no. 8, pp. 1047–1057, 1996.1047–1057, 1996.

[3] Henke, B. L.; Gullikson, E. M.; Davis, J. C. [3] Henke, B. L.; Gullikson, E. M.; Davis, J. C. At. Data Nucl. Data At. Data Nucl. Data TablesTables 1993, 54, 181. See also www-cxro.lbl.gov/optical_constants/ 1993, 54, 181. See also www-cxro.lbl.gov/optical_constants/

[4] P. Wernet, D. Nordlund, U. Bergmann, M. Cavalleri, M. Odelius, H. [4] P. Wernet, D. Nordlund, U. Bergmann, M. Cavalleri, M. Odelius, H. Ogasawara,L. A. N¨aslund, T. K. Hirsch, L. Ojamae, P. Glatzel, L. G. Ogasawara,L. A. N¨aslund, T. K. Hirsch, L. Ojamae, P. Glatzel, L. G. M. Pettersson,and A. Nilsson, “The structure of the first coordination M. Pettersson,and A. Nilsson, “The structure of the first coordination shell in liquid water,” shell in liquid water,” ScienceScience, vol. 304, no. 5673, pp. 995–999, , vol. 304, no. 5673, pp. 995–999, 2004. [Online]. Available: 2004. [Online]. Available: http://www.sciencemag.org/cgi/content/abstract/304/5673/995http://www.sciencemag.org/cgi/content/abstract/304/5673/995