Transcript Physics and Chemistry of Hybrid Organic

Physics and Chemistry of Hybrid
Organic-Inorganic Materials
Lecture 11: Polymerizing organic
monomers in inorganic materials
Key concepts
• Reasons for making an inorganic filled organic polymer hybrid:
improve strength, abrasion resistance, modulus, hardness,
inflammability,
• Metal oxide inorganic particles can be made by sol-gel, flame
synthesis
• Organic phase: organic polymers
• Inorganic particles increase viscosity
• Particle aggregation ruins hybrid effects
• smaller the particle, the greater the strength and modulus of
the hybrid
• the higher the particle concentration, the greater the strength
and modulus of the hybrid
Making Hybrid Materials: Class 1C
(Polymerizing in pores)
•Porous metal oxide
•Liquid monomer (no solvent)
•UV, heat, radiation
Non-porous composite
material
Making Hybrid Materials: Class 1C
(Polymerizing in pores)
1) Monolithic inorganic Polymer nanocomposite
from completely filling pores
2) Reinforced xerogel or aerogel by coating
aggregated particles with polymer
3) Polymerizing intercalated monomers in clay
4) Polymer surrounding colloid crystal of inorganic
First example: Monolithic inorganic Polymer
nanocomposite from completely filling pores
• Infiltration & polymerization of monomer in pores of gel
• Provides a percolating filler phase based on the original
gel skeleton
Acc. Chem. Res., 2007, 40 (9), 810–818
First example: Monolithic inorganic
Polymer nanocomposite from completely
filling pores
Transparent, tough, tailorable refractive index, abrasion resistant
Pope, E. J.; Asami, M.; Mackenzie, J. D. Transparent silica gel–PMMA composites
J. Mater. Res. 1989 4 4 1018
Reinforced xerogel or aerogel by coating
aggregated particles with polymer
Porous materials, like aerogels, are super thermal insulation,
but very weak
Monomers, such as superglue, can be polymerized directly on
surface by chemical vapor deposition
Boday, D. J.; Stover, . J.; Muriithi, B.; Keller, M. W.; Wertz, J. T.; DeFriend Obrey, K. A.; Loy, D. A.
ACS Applied Materials & Interfaces 2009, 1(7), 1364.
Reinforced xerogel or aerogel by coating
aggregated particles with polymer
monomers can be polymerized in solution if they will precipitate
onto the particles surfaces.
Epoxies, urethanes, some vinyl polymers
Acc. Chem. Res., 2007, 40 (9), pp 874–884
Polymer-Clay Nanocomposites from
intercalation & polymerization of monomers
1) First heat 100 g montmorillonite (MMT) with 51.6 g of aminolauric acid
and 24 mL conc. HCl in 10 Liters of water for 10 min.
2) Filter, was 3X with 10 L hot water, then freeze dry, then dry under vacuum
at 100 °C to afford ion exchanged, intercalated MMT
3) Mix 29.7 g intercalated MMT, 509 g caprolactam, and 66 g 6aminocaproic acid were mixed in mortar in pestle.
4) The mixture was polymerized in3000 mL round bottom flask with mech.
Stirrer and under nitrogen for 30 min at 100 °C then for 6 h at 250 °C.
5) The products were crushed in mortar & pestle, then washed with water
and dried at 89 °C.
A. Usuki, Y. Kojima, M. Kawasumi, A. Okada, Y. Fukushima,T. Kurauchi, O. Kamigaito, "Synthesis of
nylon 6-clay hybrid," J. Mater. Res. 1993, 8, 1179
Polymer colloidal crystal nanocomposites
1) Prepare a colloidal crystal (opal) from silica particles
2) Add monomer & catalyst to fill pores
3) Polymerize to form72% by volume silica filled organic polymer
4) Dissolve silica away with HF if inverse opal is desired
Microporous and Mesoporous Materials 2001,44-45, 227 - 239
Small organic phase
dispersed in continuous
inorganic phase
Making Hybrid Materials: Class 1D
(encapsulation of small organics)
• Polymerize metal oxide around organic
• pores must be small or leakage will
occur
•Solid state dye lasers, filters, colored
glass
•sunscreens
•Biopolymers
•Medicines
•Living cells
•Imprinting (artificial enzymes)
Class 1D: the organic dye is trapped
within the silica network
Simple method for encapsulating dyes.
Easily recyclable colored bottles
J. Livage
Organic dyes in a silica matrix
fluorescence - laser - NLO - photochromism
J. Livage
Optical limiters
nonlinear hybrid C60-silica coated lenses
Preventing UV-light damage of light sensitive
materials using a highly protective UV-absorbing
Hybrid (Class 1D) coating
Absorption spectrum of the UV protecting film (1 µm) with and
without the UV-absorber molecule (34 wt%).
Chem. Soc. Rev., 2007, 36, 1270-1281
Dyes are protected against
photodegradation by Class 1D matrix
Visible absorption spectra of Photosystem I entrapped in sol–gel at intervals during
the aging process compared with the solution spectrum of the native preparation. The
spectrum of a control gel without PSI that was aged for 29 days is also shown
H. O'Neill and E. Greenbaum, Chem. Mater.,
2005, 17, 2654
Fluorescent core–shell silica nanoparticles incorporating organic dyes with
different spectral characteristics, covering the entire UV-vis absorption and
emission wavelengths. (Reproduced from ref. 31, with permission. Copyright
2005 American Chemical Society.)
H. Ow, D. R. Larson, M. Srivastava, B. A. Baird,
W. W. Webb and U. Wiesner, Nano Lett., 2005,
5, 113
Sol-gel encapsulation of drugs in silica
particles using microemulsions
Water in oil emulsions
Langmuir, 1997, 13 (24), pp 6400–6406
Enzymes in sol-gel
Requires mild sol-gel (pH 7)
Enzymes remain active longer than when in water
Sensors and catalysts
Science 1992, 255, 1113– 1115
Chem. Soc. Rev., 2007, 36, 932-940
Cyctochrome C encapsulated in dry aerogels
Generally thought that water is needed for enzyme activity
Aerogels made with cytochrome C have remained active
NO sensors
Amanda S. Harper-Leatherman Langmuir, Article ASAP 2012
Bio encapsulation: Photosynthesis system
Chem. Mater., 2005, 17 (10), pp 2654–2661
Enclapsulation of liposomes in silica gel
Langmuir, 1997, 13 (19), pp 5049–5053
Encapsulating living cells in silica
Bacteria encapsulated within a silica matrix aged for (a) 1 month
without glycerol and (b) 1 day with a layer of glycerol.
Imprinting to make synthetic enzymes
in hybrid materials
Imprinting dopamine
analogs into
silsesquioxane
modified silicas for
sensors
Chem. Mater., 2003, 15 (19), pp 3607–3613
Imprinting DDT into
silsesquioxane modified
silicas for sensors
Imprinting Caffeine
into silica modified
with silsesquioxane
with non-bonding
interactions
C. Lin, A. Joseph, C.K. Chang, Y.C. Wang, Y.D. Lee Anal. Chim. Acta, 481 (2003), p. 175
Imprinting
dopamine analogs
into
silsesquioxane
modified silicas for
sensors
C.W. Hsu, M.C. Yang, J. Non-Cryst Solid, 354 (2008), p. 4037
Imprinting that generates on optical signal
when site recognizes molecule
Acc. Chem. Res., 2007, 40 (9), pp 756–
767
Summary
• Inorganic surfaces are best modified using silane coupling agents
(hydrolyzed organotrialkoxysilanes or oligosilsesquioxanes).
• Organic monomers can be added as liquid to a porous inorganic
material or adsorbed as a gas before polymerizing in the pores.
• The resulting hybrids are stronger than the polymer alone.
• Organic molecules, such as dyes, can be encapsulated into inorganic
materials, by polymerizing the inorganic around them.
• Dyes encapsulated in inorganic matrices are more stable chemically
and are less potentially hazardous.
• enzymes and even bacteria can be encapsulated in inorganic
materials
• Similarly, inorganic materials can be imprinted by polymering
inorganic materials around a template, then removing the template
to make functionalized, enzyme like pores
• Emulsion polymerization can be used to encapsulate organic
molecules, such as sunscreens, into inorganic particles.