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Surface Chemistry of Silica Nanoparticles for Soft Material Membrane Research, Study notes of Chemistry

The surface chemistry of LUDOX AS-30 silica nanoparticles and their potential use in soft material membrane research. the challenges of using monodisperse silica in organic solvents and proposes a solution involving polymer grafted nanoparticles. The document also discusses the characterization of the nanoparticles using various techniques such as DLS, SAXS, TEM, FTIR, and TGA. The document concludes with future steps for improving the dispersion of the modified silica nanoparticles and attempting a matrix-free polymerization via a solution of monomers.

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2022/2023

Uploaded on 05/11/2023

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Bridgie Cawthon1, Marshall Tekell2, Sanat Kumar2
1) Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 2) Department of Chemical Engineering,
Columbia University
FEI TALOS F200X
Introduction
Methods
Results Conclusion and Next Steps
Acknowledgements
1. Van Roosmalen, A. J., and J. C. MOL. “Cheminform Abstract: An Infrared Study of the Silica Gel Surface. 1. Dry Silica Gel.” Chemis cher Informationsdienst, vol. 10,
no. 13, 1979, https://doi.org/10.1002/chin.197913007.
2. Gun'ko, V.M., et al. “Mechanism and Kinetics of Hexamethyldisilazane Reaction with a Fumed Sili ca Surface.” Journal of Colloi d and Interface Science, vol. 228, no.
1, 2000, pp. 157170., https://doi.org/10.1006/jcis.2000.6934.
3. Jhalaria, M., Jimenez, A. M., Mathur, R., Tekell, M. C., Huang, Y., Narayanan, S., Benicewicz, B. C., & Kumar, S. K. (2022). Long-term aging in miscible polymer
nanocomposites. Macr omolec ules,55(11), 45024515. https://doi.org/10.1021/acs.macromol.2c00332
4. Yoshitake, & Kato. (2007, March 6). PROCESS FOR PRODUCING HYDROPHOBC SILCA POWDER.
Reaction Mechanism
-LUDOX AS-30 (Commercial silica, SiO2) reacts with
HMDS to attach trimethylsilyl (TMS) groups to surface
-Reaction occurs at 70 oCfor 3 hours
-Surface chemical change alters solubility properties
Scattering, Microscopy, Spectroscopy, and Gravimetric
Analysis Used to Characterize Particles
-Dynamic Light Scattering (DLS)
-Small Angle X-Ray Scattering (SAXS) (Photo by Isabella Huang)
-Transmission Electron Microscopy (TEM)
-Fourier Transform Infrared Spectroscopy (FTIR)
-Thermogravimetric Analysis (TGA)
LUDOX AS-30 Particle Size Distribution Comparison
Solubility in Methyl Ethyl Ketone
SAXS form factor image
Characterization of Surface Chemistry Using ATR-FTIR
Soft material membrane research is at the front of much
sustainability research because of their abilities in
separating green house gases, desalination of water, and
other purposes. Membranes of this nature require special
polymer grafted nanoparticles for casting. Polymerization
initiated from the surface of nanoparticles requires
compatibility between nanoparticles and common organic
solvents like methyl ethyl ketone (MEK). The resulting “hairy
nanoparticles can be used to create gas-separation
membranes with enhanced gas permeabilities and tunable
gas selectivities. However, high polydispersity hiders
selectivity. DLS: Intensity, volume, and number distribution
TEM image analysis of LUDOX AS-30
Above: The two images above left and middle show a comparison between MEK-ST and reacted
LUDOX solution in MEK. TGA analysis done on 300 μLof reacted LUDOX shows a final weight of
nanoparticle present of 28.04 mg, corresponding to a solution concentration of 93.5 mg/mL.
Nissan MEK-ST solution
Motivation: Particle shape and size distribution can be
improved using commercial silica colloids
Problem: Monodisperse silica is too hydrophilic to be used
in organic solvents
Modified LUDOX AS-30 in MEK TGA showing high solubility of Si-OH in MEK
ØA monodisperse particle size is observed (14-18 nm
diameter), and the polydispersity in particle size relative to
MEK-ST is significantly reduced.
ØLUDOX AS-30 is capable of undergoing changes is surface
chemistry, altering its hydrophobicity. This allows it to be a
suitable starting material for creating hydrophobic
monodisperse silica nanoparticles.
ØFurther improvement of the dispersion of the modified silica
is the next challenge of this problem. Additional milling and
drying techniques for the product will be tried to disrupt any
particle aggregation that may be happening.
ØOnce dispersion is optimized and controllable, the next step
is to attempt a matrix-free polymerization via a solution of
monomers. The polymer chains grafted to the surface would
then be cast into films and further analyzed.
References
Iam very grateful to have gotten the chance to work in
Dr.Kumar’s lab this summer under his PhD candidate Marshall.
Additional thanks to Dr. Avila of Chemistry for use of FTIR
instrument.
7000100 200 300 400 500 600
Temperature T(°C)
30.0
28.0
28.5
29.0
29.5
Weight (mg)
Ramp 20.00 °C/min to 120.00 °C
Isothermal 10.0 min
Ramp 30.00 °C/min to 700.00 °C
2022-06-17-1-LUDOX-rxn
Time: 33.97 min
Temperature: 677.07 °C
Weight: 28.042 mg
Weight Percent: 93.624 %
TA Instruments Trios V5.1.1.46572
3100300029002800
Frequency (cm-1)
0
0.002
0.004
0.006
0.008
0.01
0.012
3850375036503550
Absorbance
Frequency (cm-1)
Dried AS-30
Reacted AS-30

Partial preview of the text

Download Surface Chemistry of Silica Nanoparticles for Soft Material Membrane Research and more Study notes Chemistry in PDF only on Docsity!

Bridgie Cawthon

, Marshall Tekell

, Sanat Kumar

1) Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 2) Department of Chemical Engineering,

Columbia University

FEI TALOS F200X

Introduction

Methods

Results Conclusion and Next Steps

Acknowledgements

  1. Van Roosmalen, A. J., and J. C. MOL. “Cheminform Abstract: An Infrared Study of the Silica Gel Surface. 1. Dry Silica Gel.” Chemischer Informationsdienst , vol. 10, no. 13, 1979, https://doi.org/10.1002/chin.197913007.
  2. Gun'ko, V.M., et al. “Mechanism and Kinetics of Hexamethyldisilazane Reaction with a Fumed Silica Surface.” Journal of Colloid and Interface Science , vol. 228, no. 1, 2000, pp. 157–170., https://doi.org/10.1006/jcis.2000.6934.
  3. Jhalaria, M., Jimenez, A. M., Mathur, R., Tekell, M. C., Huang, Y., Narayanan, S., Benicewicz, B. C., & Kumar, S. K. (2022). Long-term aging in miscible polymer nanocomposites. Macromolecules , 55 (11), 4502–4515. https://doi.org/10.1021/acs.macromol.2c
  4. Yoshitake, & Kato. (2007, March 6). PROCESS FOR PRODUCING HYDROPHOBC SILCA POWDER. Reaction Mechanism
  • LUDOX AS-30 (Commercial silica, SiO 2 ) reacts with HMDS to attach trimethylsilyl (TMS) groups to surface
  • Reaction occurs at 70 oC for 3 hours
  • Surface chemical change alters solubility properties Scattering, Microscopy, Spectroscopy, and Gravimetric Analysis Used to Characterize Particles
  • Dynamic Light Scattering (DLS)
  • Small Angle X-Ray Scattering (SAXS) (Photo by Isabella Huang)
  • Transmission Electron Microscopy (TEM)
  • Fourier Transform Infrared Spectroscopy (FTIR)
  • Thermogravimetric Analysis (TGA) LUDOX AS-30 Particle Size Distribution Comparison Solubility in Methyl Ethyl Ketone SAXS form factor image Characterization of Surface Chemistry Using ATR-FTIR Soft material membrane research is at the front of much sustainability research because of their abilities in separating green house gases, desalination of water, and other purposes. Membranes of this nature require special polymer grafted nanoparticles for casting. Polymerization initiated from the surface of nanoparticles requires compatibility between nanoparticles and common organic solvents like methyl ethyl ketone (MEK). The resulting “hairy” nanoparticles can be used to create gas-separation membranes with enhanced gas permeabilities and tunable gas selectivities. However, high polydispersity hiders selectivity. DLS: Intensity, volume, and number distribution TEM image analysis of LUDOX AS- 30 Above: The two images above left and middle show a comparison between MEK-ST and reacted LUDOX solution in MEK. TGA analysis done on 300 μL of reacted LUDOX shows a final weight of nanoparticle present of 28.04 mg, corresponding to a solution concentration of 93.5 mg/mL. Nissan MEK-ST solution Motivation: Particle shape and size distribution can be improved using commercial silica colloids Problem: Monodisperse silica is too hydrophilic to be used in organic solvents Modified LUDOX AS-30 in MEK TGA showing high solubility of Si-OH in MEK Ø A monodisperse particle size is observed (14-18 nm diameter), and the polydispersity in particle size relative to MEK-ST is significantly reduced. Ø LUDOX AS-30 is capable of undergoing changes is surface chemistry, altering its hydrophobicity. This allows it to be a suitable starting material for creating hydrophobic monodisperse silica nanoparticles. Ø Further improvement of the dispersion of the modified silica is the next challenge of this problem. Additional milling and drying techniques for the product will be tried to disrupt any particle aggregation that may be happening. Ø Once dispersion is optimized and controllable, the next step is to attempt a matrix-free polymerization via a solution of monomers. The polymer chains grafted to the surface would then be cast into films and further analyzed.

References

I am very grateful to have gotten the chance to work in Dr. Kumar’s lab this summer under his PhD candidate Marshall. Additional thanks to Dr. Avila of Chemistry for use of FTIR instrument. 0 100 200 300 400 500 600 700 Temperature T (°C)

W e ig h t^ (m g ) Ramp 20.00 °C/min to 120.00 °C Isothermal 10.0 min Ramp 30.00 °C/min to 700.00 °C 2022-06-17-1-LUDOX-rxn Time: 33.97 min Temperature: 677.07 °C Weight: 28.042 mg Weight Percent: 93.624 % TA Instruments Trios V5.1.1. 2800 2900 3000 3100 Frequency (cm-1) 0

3550 3650 3750 3850 Absorbance Frequency (cm-1) Dried AS- Reacted AS-