Method for producing nanoparticles of a selected size
A method for producing nanoparticles of a selected size includes selecting an organic solvent based upon a molar volume of the organic solvent, the selected nanoparticle size, and a known relationship between the molar volume and the selected nanoparticle size, and producing nanoparticles having the selected size in a water-in-oil microemulsion comprising the selected organic solvent.
1. A method comprising:
forming a microemulsion comprising a surfactant, an organic solvent, and water, wherein the water forms water droplets in the microemulsion and a size of each water droplet is defined by the equation:
R
=
3
φ
C
s
Σ
,
where R is a radius of the water droplet, φ is a volume fraction of water in the microemulsion, C s is an amount of surfactant molecules per unit volume, and Σ is an area occupied by each surfactant molecule and is a function of a molar volume of the organic solvent; and
adding a nanoparticle precursor material to the microemulsion for forming nanoparticles in the water droplets, wherein the nanoparticles formed in each water droplet have a size based on the size of each water droplet.
2. The method of claim 1 , wherein the organic solvent is an alkane.
3. The method of claim 1 , wherein the organic solvent is selected from a group consisting of cyclohexane, n-pentane, n-hexane, n-heptane, n-decane, and n-hexadecane.
4. The method of claim 1 , wherein the nanoparticle precursor material is tetraethylorthosilicate.
5. The method of claim 1 , wherein the nanoparticle precursor material is tetra-tert-butyl orthotitanate.
6. The method of claim 1 , wherein sizes of the nanoparticles are in the range of about 20 nanometers to about 110 nanometers in diameter.
7. The method of claim 1 , wherein the surfactant is octylphenol ethylene oxide condensate having the chemical formula C 14 H 22 O(C 2 H 4 O) n where n=9-10.
8. The method of claim 1 , wherein the surfactant is a polyoxyethylene nonyl phenol ether having the chemical formula C 15 H 24 O(C 2 H 4 O) 5 .
9. The method of claim 1 , wherein the organic solvent comprises a blend of organic solvents having different molar volumes.
10. A method comprising:
blending a first organic solvent having a first molar volume and a second organic solvent having a second molar volume to produce an organic solvent blend having a third molar volume;
forming a water-in-oil microemulsion comprising a surfactant, water and the organic solvent blend;
adding a nanoparticle precursor material to the water-in-oil microemulsion for forming nanoparticles; and
producing nanoparticles from the nanoparticle precursor material in the water-in-oil microemulsion, wherein nanoparticle size is based on sizes of water droplets in the water-in-oil microemulsion according to the equation:
R
=
3
φ
C
s
Σ
,
where R is a radius of the water droplet, φ is a volume fraction of water in the microemulsion, C s is an amount of surfactant molecules per unit volume, and Σ is an area occupied by each surfactant molecule and is a function of a third molar volume.
11. The method of claim 10 , further comprising selecting the first and second organic solvents based on the nanoparticle size.
12. The method of claim 10 , wherein the first and second organic solvents are alkanes.
13. The method of claim 10 , wherein the first and second organic solvents are selected from a group consisting of cyclohexane, n-pentane, n-hexane, n-heptane, n-decane, and n-hexadecane.
14. The method of claim 10 , wherein the nanoparticle precursor material is tetraethylorthosilicate.
15. The method of claim 10 , wherein the nanoparticle precursor material is tetra-tert-butyl orthotitanate.
16. The method of claim 10 , wherein the nanoparticle size is in the range of about 20 nanometers to about 110 nanometers in diameter.
17. A method comprising:
selecting a nanoparticle size;
selecting an organic solvent having a molar volume; and
producing a nanoparticle having the selected nanoparticle size in a microemulsion comprising water, surfactant, and the selected organic solvent, wherein the selected nanoparticle size is defined by the equation:
R
=
3
φ
C
s
Σ
,
where R is a radius of water droplets within the microemulsion, φ is a volume fraction of water in the microemulsion, C s is an amount of surfactant molecules per unit volume, and Σ is an area occupied by each surfactant molecule and is a function of the molar volume of the organic solvent.
18. The method of claim 17 , wherein the organic solvent is an alkane.
19. The method of claim 17 , wherein the organic solvent is selected from a group consisting of cyclohexane, n-pentane, n-hexane, n-heptane, n-decane, and n-hexadecane.
20. The method of claim 17 , wherein the selected nanoparticle size is in the range of about 20 nanometers to about 110 nanometers in diameter.