Organic solid crystals having helical structures formed using negative templates
An optical film includes a block copolymer film defining a plurality of helically shaped cavities and a plurality of helically shaped organic solid crystals positioned within the plurality of helically shaped cavities. A method of making the optical film includes obtaining a film of a block copolymer solution including a chiral block copolymer and a non-chiral block copolymer on a substrate. The method includes annealing the film, thereby forming a plurality of helical structures from the chiral block copolymer defined within the non-chiral block copolymer and removing the plurality of helical structures, thereby creating a plurality of helically shaped cavities. The method further includes forming organic solid crystals inside the plurality of helically shaped cavities, thereby forming the optical film.
1. An optical film, comprising:
a block copolymer film defining a plurality of helically shaped cavities; and
a plurality of helically shaped organic solid crystals positioned within the plurality of helically shaped cavities.
2. The optical film of claim 1 , wherein an index of refraction of the organic solid crystals is at least 1.9.
3. The optical film of claim 1 , wherein the block copolymer film includes one or more non-chiral polymer selected from a group consisting of styrene, vinylnaphthalene, vinylanthracene, naphthyl acrylate, and any of:
wherein any R is independently selected from the group consisting of CH 3 , ethyl, H, OH, oxymethylene, ethoxy, isopropoxide, F, Cl, Br, I, phenyl, NO 2 , SO 3 , SO 2 Me, isopropyl, t-butyl, sec-butyl, acetyl, SH, S-methyl, carboxyl, aldehyde, amide, nitrile, ester, SO 2 NH 3 , NH 2 , NMe 2 , NMeH, or C 2 H 2 .
4. The optical film of claim 1 , wherein the plurality of helically shaped organic solid crystals includes one or more polycyclic aromatic hydrocarbons selected from a group consisting of naphthalene, anthracene, tetracene, pentacene, pyrene, polycene, fluoranthene, benzophenone, benzochromene, benzil, benzimidazole, benzene, hexachlorobenzene, nitropyridine-N-oxide, benzene-1,4-dicarboxylic acid, diphenylacetylene, N-(4-nitrophenyl)-(s)-prolinal, 4,5-dicyanoimidazole, benzodithiophene, cyanopyridine, thienothiophene, stilbene, azobenzene, and their derivatives.
5. The optical film of claim 1 , wherein the plurality of helically shaped organic solid crystals includes one or more organic ring structures that include (i) one or more saturated cyclic compounds selected from a group consisting of cyclohexane, cyclopentane, tetrahydropyran, piperidine, tetrahydrofuran, pyrrolidine, tetrahydrothiophene and their derivatives and (ii) one or more unsaturated aromatic compounds selected from a group consisting of benzene, naphthalene, anthracene, thiophene, bi-phenyl, tolane, benzimidazole, diphenylacetylene, cyanopyridine, thienothiophene, dibenzothiophene, carbazole, silafluorene and their derivatives.
6. The optical film of claim 5 , wherein the one or more organic ring structures are coupled with one or more terminal groups selected from the group consisting of C 1 -C 10 alkyl, alkenyl, —CN, —NCS, —SCN, —SF 5 , —Br, —Cl, —F, —OCF 3 , —CF 3 , mono- or polyfluorinated C 1 -C 10 alkyl, and alkoxy.
7. The optical film of claim 1 , wherein the optical film has a first surface and an opposing second surface, and the plurality of helically shaped organic solid crystals extend from the first surface to the second surface about an axis normal to the first surface.
8. The optical film of claim 1 , wherein the plurality of helically shaped organic solid crystals has a volume fraction ranging from 10% to 90% of a total volume of the optical film.
9. The optical film of claim 1 , wherein the optical film is a polarization selective optical film.
10. The optical film of claim 1 , wherein the block copolymer film has a volume fraction ranging from 10% to 90% of a total volume of the optical film.
11. The optical film of claim 1 , wherein the block copolymer film includes a chiral block copolymer, wherein the chiral block copolymer includes one or more selected from the group consisting of poly(L-lactic acid), poly(D-lactic acid), isotactic polymethylmethacrylate, isotatic polystyrene, unsaturated polymer with chiral center and any of:
wherein:
R 1 or R 3 is independently selected from CH 3 , ethyl, sec-butyl, ethyl, acetyl, SH, S-methyl, carboxyl, aldehyde, amide, nitrile, ester, SO 2 NH 3 , NH 2 , NMe 2 , NMeH, or C 2 H 2 ;
R 2 or R 5 is independently seleeted from CH 2 ;
R 4 or R 7 is independently selected from H, CH 3 , ethyl, sec-butyl, ethyl, acetyl, SH, S-methyl, carboxyl, aldehyde, amide, nitrile, ester, SO 2 NH 3 , NH 2 , NMe 2 , NMeH, or C 2 H;
R 6 is independently selected from CH 3 , ethyl, H, OH, oxymethylene, ethoxy, isopropoxide, F, Cl, Br, I, phenyl, NO 2 , SO 3 , SO 2 Me, isopropyl, t-butyl, sec-butyl, ethyl, acetyl, SH, S-methyl, carboxyl, aldehyde, amide, nitrile, ester, SO 2 NH 3 , NH 2 , NMe 2 , NMeH, or C 2 H; and
R 8 is independently selected from CH 3 , ethanol, H, OH, oxymethylene, ethoxy, isopropoxide, F, Cl, Br, I, phenyl, NO 2 , SO 3 , SO 2 Me, isopropyl, t-butyl, sec-butyl, acetyl, SH, S-methyl, carboxyl, aldehyde, amide, nitrile, ester, SO 2 NH 3 , NH 2 , NMe 2 , NMeH, or C 2 H 2 .
12. The optical film of claim 1 , wherein the plurality of helically shaped organic solid crystals includes one or more polycyclic aromatic hydrocarbons selected from a group consisting of naphthalene, anthracene, tetracene, pentacene, pyrene, polycene, fluoranthene, benzophenone, benzochromene, benzil, benzimidazole, benzene, hexachlorobenzene, nitropyridine-N-oxide, benzene-1,4-dicarboxylic acid, diphenylacetylene, N-(4-nitrophenyl)-(s)-prolinal, 4,5-dicyanoimidazole, benzodithiophene, cyanopyridine, thienothiophene, stilbene, azobenzene, and their derivatives.
13. The optical film of claim 1 , wherein the plurality of helically shaped organic solid crystals includes one or more organic ring structures that include (i) one or more saturated cyclic compounds selected from a group consisting of cyclohexane, cyclopentane, tetrahydropyran, piperidine, tetrahydrofuran, pyrrolidine, tetrahydrothiophene and their derivatives and (ii) one or more unsaturated aromatic compounds selected from a group consisting of benzene, naphthalene, anthracene, thiophene, bi-phenyl, tolane, benzimidazole, diphenylacetylene, cyanopyridine, thienothiophene, dibenzothiophene, carbazole, silafluorene and their derivatives.
14. The optical film of claim 13 , wherein the one or more organic ring structures are coupled with one or more terminal groups selected from the group consisting of C 1 -C 10 alkyl, alkenyl, —CN, —NCS, —SCN, —SF 5 , —Br, —Cl, —F, —OCF 3 , —CF 3 , mono- or polyfluorinated C 1 -C 10 alkyl, and alkoxy.