1. An aqueous dispersion of a vinyl esterethylene copolymer prepared by emulsion copolymerization of a monomer mixture comprising a vinyl ester and ethylene, less than 0.5 ppmw of a surfactant, and a polyvinyl alcohol stabilizing system consisting essentially of (a) about 0.5 to about 3 wt. % based on the total monomer weight of a first polyvinyl alcohol having a degree of hydrolysis of at least 98 mole %, and (b) about 1 to about 4 wt. % based on the total monomer weight of a second polyvinyl alcohol having a degree of hydrolysis of about 85 to about 90 mole % and a weight average molecular weight of at least 85,000 gmol.
2. The dispersion of claim 1, wherein the stabilizing system contains about 1 to about 2 wt. % of said first polyvinyl alcohol based on the total monomer mixture.
3. The dispersion of claim 1, wherein the stabilizing system contains about 2 to about 3 wt. % of a second polyvinyl alcohol based on the total monomer mixture.
4. The dispersion of claim 1, wherein the second polyvinyl alcohol has a weight average molecular weight of about 85,000 to about 125,000 gmol.
5. The dispersion of claim 1 and having a Viscosity Increasing Ratio (VIR) of at least 7 when mixed with 10 wt. % of diisobutyl phthalate.
6. The dispersion of claim 1 and having a viscosity of at least 4000 mPas at 55% solids and 25\xb0 C.
7. The dispersion of claim 1 and containing less than 10 ppmw formaldehyde.
8. The dispersion of claim 1 and having an average particle size between about 2 and about 10 \u03bcm.
9. The dispersion of claim 1, wherein the copolymer contains from about 5 to about 25 wt. % of units derived from ethylene.
10. The dispersion of claim 1, wherein the copolymer contains from about 10 to about 20 wt. % of units derived from ethylene.
11. The dispersion of claim 1, wherein the copolymer contains from about 14 to about 16 wt. % of units derived from ethylene.
12. The dispersion of claim 1, wherein the vinyl ester comprises a vinyl ester of a C1-C13 saturated carboxylic acid.
13. The dispersion of claim 1, wherein the vinyl ester comprises vinyl acetate.
14. An adhesive formulation comprising the aqueous dispersion of claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system of miniature lenses, the system comprising:
a substrate comprising one or more patterns, wherein each of the patterns includes a repeating unit; and
a plurality of miniature lenses disposed on the substrate,
wherein a size of the repeating unit corresponds to a size of the miniature lenses,
wherein at least one of the patterns comprises elevated structures at regular intervals, and
wherein each of the miniature lenses is disposed between the elevated structures.
2. A method of making the system of miniature lenses of claim 1, the method comprising:
providing a film on a substrate comprising one or more patterns, each of the patterns including a repeating unit, and wherein the film comprises a polymer;
transitioning the polymer to a viscous state to form a viscous state polymer;
facilitating the formation of a plurality of miniature lenses from the viscous state polymer; and
transitioning the viscous state polymer in the miniature lenses from the viscous state to a rigid state, wherein a size of the repeating unit corresponds to a size of the miniature lenses,
whereby said system of miniature lenses is formed.
3. The method of claim 2, wherein transitioning the polymer to viscous state comprises: reducing the glass transition temperature of the polymer andor heating the polymer above the glass transition temperature of the polymer.
4. The method of claim 3, wherein reducing the glass transition temperature of the polymer comprises: contacting the polymer with a solvent effective to reduce the glass transition temperature of the polymer.
5. The method of claim 4, wherein the solvent comprises water and one or more organic solvents selected from the group consisting of: acetone, methyl-ethyl ketone, tetrahydrofuran, andor combinations thereof.
6. The method of claim 5, wherein the solvent comprises water in a range of about 30% to about 90% by volume, acetone in a range of about 5% to about 20% by volume, and methyl-ethyl ketone in a range of about 20% to about 40% by volume.
7. The method of claim 4, wherein transitioning the polymer in the miniature lenses to the rigid state comprises: removing the solvent from polymer andor cooling the polymer below the glass transition temperature.
8. The method of claim 2, wherein the polymer comprises one or more polymers selected from the group consisting of: polystyrene, polyacrylates, polymethacrylates, poly(vinyl ethers), polybutadiene, andor combinations thereof.
9. The method of claim 8, wherein the polymer is selected from the group consisting of: polystyrene, polymethylmethacrylate, andor combinations thereof.
10. The method of claim 2, wherein at least one of the patterns in the substrate comprises a plurality of structures positioned at predetermined intervals.
11. The method of claim 10, wherein the predetermined intervals are less than about 1,000 \u03bcm.
12. The method of claim 2, wherein the film is less than about 200 nm in thickness.
13. The method of claim 2, wherein the miniature lenses comprise lenses having a diameter in a range of about 200 nm to about 10 \u03bcm.
14. The method of claim 2, wherein the miniature lenses are generally spherical in shape.
15. The system of claim 1, wherein the plurality of miniature lenses each comprise at least 50% by weight of one or more common polymers.
16. The system of claim 15, wherein the one or more common polymers are selected from the group consisting of polystyrene, polyacrylates, polymethacrylates, poly(vinyl ethers), polybutadiene, andor combinations thereof.
17. The system of claim 16, wherein the common polymer is selected from the group consisting of polystyrene, polymethylmethacrylate, andor combinations thereof.
18. The system of claim 1, wherein at least one of the patterns comprises a plurality of structures positioned at predetermined intervals.
19. The system of claim 1, wherein the substrate comprises a silicon layer.
20. The system of claim 1, wherein the miniature lenses are generally spherical in shape.
21. The system of miniature lenses of claim 1, wherein:
the plurality of miniature lenses have an average contact angle in the range from about 50\xb0 to about 150\xb0; and
each of the plurality of miniature lenses have a contact angle in the range from about 80% to about 120% of the average contact angle.
22. A method of making the system of miniature lenses of claim 21, the method comprising:
providing a film on a substrate, wherein the film comprises a polymer;
transitioning the polymer to a viscous state to form a viscous state polymer;
facilitating the formation of a plurality of miniature lenses from the viscous state polymer; and
transitioning the viscous state polymer in the miniature lenses from the viscous state to a rigid state, wherein the plurality of miniature lenses have an average contact angle in the range from about 50\xb0 to about 150\xb0, and each of the plurality of miniature lenses have a contact angle in the range from about 80% to about 120% of the average contact angle
whereby said system of miniature lenses is formed.
23. The system of claim 1, wherein each of the miniature lenses is approximately equidistant to three or more of the elevated structures nearest to each miniature lens.
24. The system of claim 1, wherein at least one of the patterns comprises a rhombic lattice, a hexagonal lattice, a rectangular lattice, or a parrallelogrammic lattice.
25. The system of claim 1, further comprising:
a solvent, wherein the plurality of miniature lenses and the substrate are immersed in the solvent.
26. A system of miniature lenses, the system comprising:
a substrate comprising one or more patterns, wherein each of the patterns includes a repeating unit; and
a plurality of miniature lenses disposed on the substrate,
wherein a size of the repeating unit corresponds to a size of the miniature lenses,
wherein the miniature lenses comprise lenses having a diameter in a range of about 200 nm to about 10 \u03bcm.
27. The system of claim 26, wherein each of the plurality of miniature lenses have a diameter in the range from about 80% to about 120% of the average diameter.
28. The system of claim 26, wherein the plurality of miniature lenses have an average contact angle in the range from about 30\xb0 to about 150\xb0, and each of the plurality of miniature lenses have a contact angle in the range from about 80% to about 120% of the average contact angle.
29. The system of claim 26, wherein the plurality of miniature lenses have an average contact angle in the range from about 50\xb0 to about 150\xb0.