COMPOSITION FOR NANOENCAPSULATION AND NANOCAPSULES COMPRISING A LIQUID-CRYSTALLINE MEDIUM

Abstract

The present invention relates to compositions for nanoencapsulation which comprise the mesogenic medium as set forth in claim 1, one or more polymerizable compounds and one or more surfactants, to nanocapsules containing the mesogenic medium and to their use in electro-optical devices.

Claims

1. A composition for nanoencapsulation, comprising (i) a mesogenic medium which comprises one or more compounds of formula I
R-A-Y-A-RI wherein R and R denote, independently of one another, a group selected from F, CF.sub.3, OCF.sub.3, CN, and straight-chain or branched alkyl or alkoxy having 1 to 15 carbon atoms or straight-chain or branched alkenyl having 2 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or mono- or polysubstituted by halogen and wherein one or more CH.sub.2 groups may be, in each case independently of one another, replaced by O, S, CO, COO, OCO, OCOO or CC in such a manner that oxygen atoms are not linked directly to one another, A and A denote, independently of one another, a group selected from -Cyc-, -Phe-, -Cyc-Cyc-, -Cyc-Phe-, -Phe-Phe-, -Cyc-Cyc-Cyc-, -Cyc-Cyc-Phe-, -Cyc-Phe-Cyc-, -Cyc-Phe-Phe-, -Phe-Cyc-Phe-, -Phe-Phe-Phe- and the respective mirror images thereof, wherein Cyc is trans-1,4-cyclohexylene, in which one or two non-adjacent CH.sub.2 groups may be replaced by O, and wherein Phe is 1,4-phenylene, in which one or two non-adjacent CH groups may be replaced by N and which may be substituted by one or two F, and Y denotes single bond, COO, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, CH.sub.2O, CF.sub.2O, CHCH, CFCF or CC, (ii) one or more polymerizable compounds, and (iii) one or more surfactants.

2. The composition according to claim 1, which further comprises one or more organic solvents.

3. The composition according to claim 1, wherein the one or more polymerizable compounds (ii) as set forth in claim 1 comprise polymerizable groups selected from one, two or more acrylate, methacrylate and vinyl acetate groups.

4. The composition according to claim 1, wherein the one or more surfactants (iii) as set forth in claim 1 are selected from nonionic surfactants.

5. The composition according to claim 1, wherein the one or more surfactants are provided as aqueous surfactant(s).

6. The composition according to claim 1, wherein the one or more compounds of formula I are selected from the compounds of formulae Ia, Ib and Ic ##STR00234## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 denote, independently of one another, straight-chain or branched alkyl or alkoxy having 1 to 15 carbon atoms or straight-chain or branched alkenyl having 2 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or mono- or polysubstituted by halogen and wherein one or more CH.sub.2 groups may be, in each case independently of one another, replaced by O, S, CO, COO, OCO, OCOO or CC in such a manner that oxygen atoms are not linked directly to one another, X.sup.1 denotes F, CF.sub.3, OCF.sub.3 or CN, L.sup.1, L.sup.2, L.sup.3 and L.sup.4 are, independently of one another, H or F, i is 1 or 2, and j and k are, independently of one another, 0 or 1.

7. The composition according to claim 1, wherein the composition is dispersed in an aqueous phase.

8. The composition according to claim 1, which is provided as nanodroplets dispersed in an aqueous phase.

9. (canceled)

10. Nanocapsules, which respectively comprise a polymeric shell, and a core containing a mesogenic medium which comprises one or more compounds of formula I as set forth in claim 1.

11. Nanocapsules obtained by or obtainable from polymerization of the composition according to claim 1.

12. The nanocapsules according to claim 10, wherein the mesogenic medium further comprises one or more chiral dopants and/or one or more pleochroic dyes.

13. A method for preparing nanocapsules, wherein the method comprises (a) providing an aqueous mixture which comprises the composition according to claim 1, (b) agitating the provided aqueous mixture to obtain nanodroplets comprising the composition dispersed in an aqueous phase, (c) subsequent to step (b) polymerizing the one or more polymerizable compounds in the composition to obtain nanocapsules each comprising a polymeric shell and a core which contains the mesogenic medium, and optionally (d) depleting, removing or exchanging the aqueous phase.

14. The method according to claim 13, wherein step (b) is carried out using a high-pressure homogenizer.

15. Nanocapsules obtained by or obtainable from carrying out the method according to claim 13.

16. The nanocapsules according to claim 10, wherein the average size of the nanocapsules is not greater than 400 nm, preferably not greater than 250 nm.

17. The nanocapsules according to claim 10, which are dried or dispersed in an aqueous phase.

18. A composite system, comprising the nanocapsules according to claim 10, and one or more binders.

19. The composite system according to claim 18, wherein the one or more binders comprise polyvinyl alcohol.

20. A light-modulation element or an electro-optical device comprising the nanocapsules according to claim 10.

21. An electro-optical device, comprising the nanocapsules according to claim 10.

22. A light-modulation element or an electro-optical device comprising the composite system according to claim 18.

Description

EXAMPLES

[0271] In the Examples, [0272] V.sub.o denotes threshold voltage, capacitive [V] at 20 C., [0273] n.sub.e denotes extraordinary refractive index at 20 C. and 589 nm, [0274] n.sub.o denotes ordinary refractive index at 20 C. and 589 nm, [0275] n denotes optical anisotropy at 20 C. and 589 nm, [0276] .sub. denotes dielectric permittivity parallel to the director at 20 C. and 1 kHz, [0277] .sub. denotes dielectric permittivity perpendicular to the director at 20 C. and 1 kHz, [0278] denotes dielectric anisotropy at 20 C. and 1 kHz, [0279] cl.p., T(N,I) denotes clearing point [ C.], [0280] .sub.1 denotes rotational viscosity measured at 20 C. [mPa.Math.s], determined by the rotation method in a magnetic field, [0281] K.sub.1 denotes elastic constant, splay deformation at 20 C. [pN], [0282] K.sub.2 denotes elastic constant, twist deformation at 20 C. [pN], [0283] K.sub.3 denotes elastic constant, bend deformation at 20 C. [pN],

[0284] The term threshold voltage for the present invention relates to the capacitive threshold (V.sub.0), unless explicitly indicated otherwise. In the Examples, as is generally usual, the optical threshold can also be indicated for 10% relative contrast (V.sub.10).

Reference Example 1

[0285] A liquid-crystal mixture B-1 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00007 Base Mixture B-1 CPGP-5-2 5.00% Clearing point [ C.]: 102.0 CPGP-5-3 5.00% n [589 nm, 20 C.]: 0.249 PGUQU-3-F 6.00% n.sub.e [589 nm, 20 C.]: 1.761 PGUQU-5-F 8.00% [1 kHz, 20 C.]: 14.2 PGU-3-F 8.00% .sub. [1 kHz, 20 C.]: 18.3 PUQU-3-F 17.00% K.sub.1 [pN, 20 C.]: 16.8 PCH-3O1 10.00% K.sub.3 [pN, 20 C.]: 16.8 PGIGI-3-F 6.00% .sub.1 [mPa .Math. s, 20 C.]: 282 PPTUI-3-2 10.00% V.sub.0 [20 C., V]: 1.13 PPTUI-3-4 15.00% PTP-1O2 5.00% PTP-2O1 5.00% 100.00%

Reference Example 2

[0286] A liquid-crystal mixture B-2 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00008 Base Mixture B-2 CPGP-5-2 3.00% Clearing point [ C.]: 118.5 DGUQU-4-F 4.00% n [589 nm, 20 C.]: 0.274 PGUQU-3-F 8.00% n.sub.e [589 nm, 20 C.]: 1.783 PGUQU-4-F 10.00% [1 kHz, 20 C.]: 15.3 PGUQU-5-F 10.00% .sub. [1 kHz, 20 C.]: 19.0 PCH-3O1 15.00% K.sub.1 [pN, 20 C.]: PPTUI-3-2 15.00% K.sub.3 [pN, 20 C.]: PPTUI-3-4 25.00% .sub.1 [mPa .Math. s, 20 C.]: PTP-1O2 5.00% V.sub.0 [20 C., V]: PTP-2O1 5.00% 100.00%

Reference Example 3

[0287] A liquid-crystal mixture B-3 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00009 Base Mixture B-3 APUQU-3-F 8.00% Clearing point [ C.]: 128 BCH-3.F.F.F 15.00% n [589 nm, 20 C.]: 0.206 CCGU-3-F 8.00% n.sub.e [589 nm, 20 C.]: 1.711 CPGP-5-2 4.00% [1 kHz, 20 C.]: 42.7 CPGP-5-3 4.00% .sub. [1 kHz, 20 C.]: 48.2 CPGU-3-OT 8.00% K.sub.1 [pN, 20 C.]: DPGU-4-F 4.00% K.sub.3 [pN, 20 C.]: PGU-2-F 10.00% .sub.1 [mPa .Math. s, 20 C.]: PGU-3-F 11.00% V.sub.0 [20 C., V]: PGUQU-3-F 8.00% PGUQU-4-F 10.00% PGUQU-5-F 10.00% 100.00%

Reference Example 4

[0288] A liquid-crystal mixture B-4 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00010 Base Mixture B-4 CPGP-5-2 5.00% Clearing point [ C.]: 134.1 CPGP-5-3 5.00% n [589 nm, 20 C.]: 0.206 DPGU-4-F 8.00% n.sub.e [589 nm, 20 C.]: 1.751 PGUQU-3-F 8.00% [1 kHz, 20 C.]: 7.2 PGUQU-5-F 4.00% .sub. [1 kHz, 20 C.]: 10.9 PGP-1-2V 14.00% K.sub.1 [pN, 20 C.]: PGP-2-2V 14.00% K.sub.3 [pN, 20 C.]: PGP-2-3 6.00% .sub.1 [mPa .Math. s, 20 C.]: PGP-3-2V 13.00% V.sub.0 [20 C., V]: PCH-3O1 18.00% PGIGI-3-F 5.00% 100.00%

Reference Example 5

[0289] A liquid-crystal mixture B-5 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00011 Base Mixture B-5 PGU-3-F 10.00% Clearing point [ C.]: 107.0 PUQU-3-F 13.00% n [589 nm, 20 C.]: 0.301 PGUQU-3-F 6.00% n.sub.e [589 nm, 20 C.]: 1.818 PCH-3O1 7.00% [1 kHz, 20 C.]: 9.6 PTP-1O2 7.00% .sub. [1 kHz, 20 C.]: 13.2 PTP-2O1 5.00% K.sub.1 [pN, 20 C.]: PPTUI-3-2 36.00% K.sub.3 [pN, 20 C.]: PTUI-3-4 16.00% .sub.1 [mPa .Math. s, 20 C.]: 100.00% V.sub.0 [20 C., V]:

Reference Example 6

[0290] A liquid-crystal mixture B-6 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00012 Base Mixture B-6 CPGP-5-2 5.00% Clearing point [ C.]: 128.9 CPGP-5-3 5.00% n [589 nm, 20 C.]: 0.212 DPGU-4-F 4.00% n.sub.e [589 nm, 20 C.]: 1.723 PGUQU-3-F 8.00% [1 kHz, 20 C.]: 6.2 PGUQU-5-F 6.00% .sub. [1 kHz, 20 C.]: 9.6 PGP-1-2V 14.00% K.sub.1 [pN, 20 C.]: PGP-2-2V 13.00% K.sub.3 [pN, 20 C.]: PGP-2-3 6.00% .sub.1 [mPa .Math. s, 20 C.]: PGP-3-2V 9.00% V.sub.0 [20 C., V]: CC-3-V 22.00% PGIGI-3-F 8.00% 100.00%

Reference Example 7

[0291] A liquid-crystal mixture B-7 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00013 Base Mixture B-7 PY-3-O2 8.00% Clearing point [ C.]: 88.0 PY-5-O2 8.00% n [589 nm, 20 C.]: 0.205 PGIGI-3-F 8.00% n.sub.e [589 nm, 20 C.]: 1.708 PP-1-2V 4.00% [1 kHz, 20 C.]: 3.2 PP-1-2V1 6.00% .sub. [1 kHz, 20 C.]: BCH-32 6.00% K.sub.1 [pN, 20 C.]: CPY-2-O2 9.00% K.sub.3 [pN, 20 C.]: CPY-3-O2 9.00% .sub.1 [mPa .Math. s, 20 C.]: 147 PYP-2-3 10.00% V.sub.0 [20 C., V]: 2.30 PGIY-2-1 8.00% PGIY-3-1 8.00% PGIY-2-O4 8.00% PGIY-3-O4 8.00% 100.00%

Reference Example 8

[0292] A liquid-crystal mixture B-8 is prepared and characterized with respect to its general physical properties, having the composition and properties as indicated in the following table.

TABLE-US-00014 Base Mixture B-8 DGUQU-4-F 3.00% Clearing point [ C.]: 85.5 DPGU-4-F 2.00% n [589 nm, 20 C.]: 0.208 PGUQU-3-F 8.00% n.sub.e [589 nm, 20 C.]: 1.705 PGUQU-4-F 9.00% [1 kHz, 20 C.]: 24.0 PGUQU-5-F 10.00% .sub. [1 kHz, 20 C.]: 28.4 PGU-3-F 5.00% K.sub.1 [pN, 20 C.]: PPTUI-3-2 11.00% K.sub.3 [pN, 20 C.]: PPTUI-3-4 15.00% .sub.1 [mPa .Math. s, 20 C.]: PUQU-3-F 13.00% V.sub.0 [20 C., V]: CC-3-O1 15.00% PCH-3O1 9.00% 100.00%

Example 1

Preparation of Nanocapsules

[0293] LC mixture B-1 (2.66 g), hexadecane (0.66 g) and methyl methacrylate (3.30 g) are weighed into a 250 ml tall beaker.

[0294] Brij L23 (0.83 g) is weighed into a 250 ml conical flask and water (100 ml) is added. This mixture is then sonicated for 5 to 10 minutes.

[0295] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 5 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is passed through a high-pressure homogenizer at 30,000 psi four times.

[0296] The mixture is charged into a flask and fitted with a condenser, and after adding AIBN (35 mg) is heated to 70 C. for three hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

[0297] The obtained capsules have an average size of 85 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0298] One part of the obtained sample is further used as is.

[0299] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is redispersed in 1 ml of the supernatant and sampled for testing.

[0300] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

Preparation of a 30% Solid Content PVA Binder

[0301] The PVA (molecular weight M.sub.w of PVA: 31 k; 88% hydrolysed) is first washed to remove ions in a Soxhlet apparatus for 3 days.

[0302] 46.66 g of ion-free water are added to a 150 ml bottle, a large magnetic stirrer bar is added and the bottle is placed on a 50 C. stirrer hotplate and allowed to come to temperature. 20.00 g of the solid washed 31 k PVA are weighed into a beaker. A vortex is created in the bottle and gradually the 31 k PVA is added over approximately 5 minutes, stopping to allow the floating PVA to disperse into the mixture. The hotplate is turned up to 90 C. and stirring is continued for 2-3 hours. The bottle is placed in oven at 80 C. for 20 hours. The mixture is filtered whilst still warm through a 50 m cloth filter under an air pressure of 0.5 bar. The filter is replaced with a Millipore 5 m SVPP filter and the filtration is repeated.

[0303] The solid content of the filtered binder is measured 3 times and the average is calculated by weighing an empty DSC pan using a DSC microbalance, adding approximately 40 mg of the binder mixture to the DSC pan and recording the mass, placing the pan on a 60 C. hotplate for 1 hour followed by 110 C. hotplate for 10 min, removing the pan from the hotplate and allowing to cool, recording the mass of the dry pan, and calculating the solid content.

Preparation of Composite System

[0304] The obtained nanocapsule sample is initially checked by microscopy for unwanted clumping or lumping, and also after film forming. The solid content of the concentrated nanocapsule suspension is measured, wherein the solid content of the sample is measured 3 times and the average is calculated. The sample is weighed in an empty DSC pan using the DSC microbalance. Approximately 40 mg of the sample is added to the DSC pan and the mass is recorded. The pan is placed on a 60 C. hotplate for 1 hour followed by 110 C. hotplate for 10 min. The pan is removed from the hotplate and allowed to cool. The mass of the dry pan is recorded, and the solid content is calculated.

[0305] The prepared PVA is added to the concentrated nanocapsule sample, wherein the approximately 30% washed 31 k PVA mixture is added in a 2.5 ml vial, and then the nanocapsules are added to the vial. Ion-free water is added to give a total solids content of 20% of an approximately 0.5 g mixture. The mixture is stirred using a vortex stirrer and leaving the mixture on a roller overnight to allow the PVA to disperse.

Film Preparation on Substrate

[0306] The substrate used is IPS (in-plane switching) glass having ITO coated interdigitated electrodes with an electrode width of 4 m and a gap of 8 m. The substrate is placed in a rack and plastic box for washing. Deionised water is added and the sample is placed in a sonicator for 10 minutes. The substrate is removed from the water and blotted with a paper towel to remove the excess water. Washing is repeated with acetone, 2-propanol (IPA) and finally water for ion-chromatography. The substrate is then dried using a compressed air gun. The substrate is treated with UV-ozone for 10 minutes.

[0307] The composite system comprising the nanocapsules and the binder is then coated on the substrate. 40 L of mixture are coated as a film using a coating machine (K Control Coater, RK PrintCoat Instruments, bar coating with k bar 1, coating speed of 7). The sample is dried at 60 C. for 10 minutes on a hotplate, under a lid to prevent draughts and stop contaminants falling onto the film. The appearance of the film is recorded. Prepared films are stored in a dry box between measurements.

[0308] Film thickness is measured by removing the film from above the electrical contacts with a razor blade. The film thickness is measured in the region of the middle electrode using a profilometer (Dektak XT surface profiler, Bruker) with a stylus force of 5 mg and a scan length of 3000 nm and a time of 30 s. The desired film thickness of 4.0-5.5 microns is observed.

Measurement of Electro-Optical Properties

[0309] The appearance of the film is checked by eye for uniformity and defects. Two electrodes are soldered to the glass. Voltage-transmission curves are measured using the dynamic scattering mode (DSM).

[0310] Images of the dark and light state are also recorded using a microscope at the required voltages for 10% and 90% transmission.

[0311] Switching speeds are measured at 40 C. and 25 C. at 150 Hz modulation frequency, and also at 10 Hz as appropriate.

[0312] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0313]

TABLE-US-00015 Capsule content 3.8% V.sub.10 20 V Max. transmission 1.54%

Example 2

[0314] LC mixture B-1 (2.0 g), ethylene dimethacrylate (0.60 g), 2-hydroxy ethylmethacrylate (0.07 g), methyl methacrylate (0.15 g) and hexadecane (0.10 g) are weighed into a 250 ml tall beaker.

[0315] This mixture is treated and investigated as described above in Example 1.

[0316] The obtained capsules have an average size of 124 nm, as determined by DLS (Zetasizer) analysis.

[0317] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0318] A composite system and a film comprising the obtained capsules and the binder are prepared as described above in Example 1.

[0319] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0320]

TABLE-US-00016 Max. transmission 19.16% V.sub.10 17 V Capsule content 14.4%

Example 3

[0321] LC mixture B-1 (2.0 g), ethylene dimethacrylate (0.66 g), hydroxy ethylmethacrylate (0.08 g), methyl methacrylate (0.16 g) and 2-isopropoxy ethanol (0.10 g) are weighed into a 250 ml tall beaker.

[0322] This mixture is treated and investigated as described above in Example 1.

[0323] The obtained capsules have an average size of 204 nm, as determined by DLS (Zetasizer) analysis.

[0324] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0325] A composite system and a film comprising the obtained capsules and the binder are prepared as described above in Example 1.

[0326] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0327]

TABLE-US-00017 Capsule content 39.9% V.sub.10 55 V Max. transmission 21.6% t.sub.on (ms) 0.27 t.sub.off (ms) 0.89

Example 4

[0328] LC mixture B-1 (1.0 g), hexanediol diacrylate (0.03 g), hydroxy ethylmethacrylate (0.03 g), isobornyl methacrylate (0.110 g) and 2-ethylhexyl acrylate (0.250 g) are weighed into a 250 ml tall beaker.

[0329] This mixture is treated and investigated as described above in Example 1.

[0330] The obtained capsules have an average size of 114 nm, as determined by DLS (Zetasizer) analysis.

[0331] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0332] A composite system and a film comprising the obtained capsules and the binder are prepared as described above in Example 1.

[0333] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0334]

TABLE-US-00018 Capsule content 2.10% V.sub.10 15 V Max. transmission 1.25%

Example 5

[0335] LC mixture B-2 (2.0 g), ethylene dimethacrylate (0.66 g), 2-hydroxy ethylmethacrylate (0.075 g), methyl methacrylate (0.175 g) and hexadecane (0.10 g) are weighed into a 250 ml tall beaker.

[0336] This mixture is treated and investigated as described above in Example 1.

[0337] The obtained capsules have an average size of 148 nm, as determined by DLS (Zetasizer) analysis.

[0338] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0339] A composite system and a film comprising the obtained capsules and the binder are prepared as described above in Example 1.

[0340] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0341]

TABLE-US-00019 Capsule content 9.8% V.sub.10 35 V Max transmission 1.25% t.sub.on (ms) 3.8 t.sub.off (ms) 4.5

Example 6

[0342] LC mixture B-3 (1.0 g), ethylene dimethacrylate (0.34 g), 2-hydroxy ethylmethacrylate (0.07 g) and hexadecane (0.25 g) are weighed into a 250 ml tall beaker.

[0343] This mixture is treated and investigated as described above in Example 1.

[0344] The obtained capsules have an average size of 145 nm, as determined by DLS (Zetasizer) analysis.

[0345] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0346] A composite system and a film comprising the obtained capsules and the binder are prepared as described above in Example 1.

[0347] The measured electro-optical parameters for the prepared film comprising the nanocapsules and the binder are given in the following Table.

Electro-Optical Parameters

[0348]

TABLE-US-00020 Capsule content 6.28% V.sub.10 15 V Max. transmission 3.6% t.sub.on (ms) 3.8 t.sub.off (ms) 4.5

Example 7

[0349] LC mixture B-4 is treated as described above in Example 2 to prepare nanocapsules, a composite system with binder and a coated film.

Example 8

[0350] LC mixture B-5 is treated as described above in Example 2 to prepare nanocapsules, a composite system with binder and a coated film.

Example 9

[0351] LC mixture B-6 is treated as described above in Example 2 to prepare nanocapsules, a composite system with binder and a coated film.

Example 10

[0352] LC mixture B-7 is treated as described above in Example 2 to prepare nanocapsules, a composite system with binder and a coated film.

Example 11

[0353] LC mixture B-1 (2.00 g), 1,4-pentanediol (102 mg), ethylene dimethacrylate (658 mg), 2-hydroxyethyl methacrylate (77 mg) and methyl methacrylate (162 mg) are weighed into a 250 ml tall beaker.

[0354] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0355] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0356] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0357] The obtained capsules have an average size of 180 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0358] One part of the obtained sample is further used as is.

[0359] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0360] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0361] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.6 m.

[0362] The measured electro-optical parameter V.sub.50, i.e. the mid-grey voltage for 50% relative contrast, is 55 V.

[0363] The prepared sample shows favourable performance at 24 C., 40 C. and 60 C., exhibiting suitable temperature dependence and stability.

Example 12

[0364] LC mixture B-1 (1.00 g), 1,4-pentanediol (175 mg), ethylene dimethacrylate (300 mg), 2-hydroxyethyl methacrylate (40 mg) and methyl methacrylate (100 mg) are weighed into a 250 ml tall beaker.

[0365] Brij L23 (50 mg) is weighed into a 250 ml conical flask and water (150 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0366] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for ten minutes.

[0367] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (10 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0368] The obtained capsules have an average size of 175 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0369] One part of the obtained sample is further used as is.

[0370] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0371] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0372] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The sample shows in particular favourable temperature dependence.

Example 13

[0373] LC mixture B-8 (1.99 g), hexadecane (101 mg), ethylene dimethacrylate (657 mg), 2-hydroxyethyl methacrylate (74 mg) and methyl methacrylate (170 mg) are weighed into a 250 ml tall beaker.

[0374] Brij L23 (300 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0375] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0376] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0377] The obtained capsules have an average size of 132 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0378] One part of the obtained sample is further used as is.

[0379] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0380] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0381] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.2 m.

[0382] The measured electro-optical parameter V.sub.50 is 33 V, and the measured electro-optical parameter V.sub.90 is 66 V.

Example 14

[0383] LC mixture B-1 (1.00 g), hexadecane (175 mg), ethylene glycol dimethacrylate (300 mg), 2-hydroxyethyl methacrylate (40 mg) and methyl methacrylate (100 mg) are weighed into a 250 ml tall beaker.

[0384] Brij L23 (50 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0385] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0386] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (10 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0387] The obtained capsules have an average size of 199 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0388] One part of the obtained sample is further used as is.

[0389] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0390] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0391] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 5.3 m.

[0392] The measured electro-optical parameter V.sub.50 is 19 V, and the measured electro-optical parameter V.sub.90 is 42 V.

Example 15

[0393] LC mixture B-1 is treated as described above in Example 14 to prepare nanocapsules, a composite system with binder and a coated film, where instead of hexadecane 1,4-pentanediol is used.

Example 16

[0394] LC mixture B-8 is treated analogous to B-1 as described above in Example 14.

Example 17

[0395] LC mixture B-8 (2.01 g), hexadecane (97 mg), ethylene dimethacrylate (645 mg), 2-hydroxyethyl methacrylate (166 mg), 1,1,1,3,3,3-hexafluoroisopropyl acrylate (23 mg) and methyl methacrylate (67 mg) are weighed into a 250 ml tall beaker.

[0396] Brij L23 (150 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0397] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0398] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0399] The obtained capsules have an average size of 176 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0400] One part of the obtained sample is further used as is.

[0401] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0402] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0403] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.2 m.

[0404] The measured electro-optical parameter V.sub.50 is 48 V, and the measured electro-optical parameter V.sub.90 is 82 V.

Example 18

[0405] LC mixture B-8 (0.99 g), hexadecane (251 mg), stearylmethacrylate (74 mg) and 1,1-dihydroperfluoropropyl acrylate (118 mg) are weighed into a 250 ml tall beaker.

[0406] Brij L23 (301 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0407] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is ultra-sonicated on a Branson sonifier W450 at 50% amplitude for a total of six minutes.

[0408] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (10 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0409] The obtained capsules have an average size of 191 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0410] One part of the obtained sample is further used as is.

[0411] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0412] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0413] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1.

Example 19

[0414] LC mixture B-8 (2.01 g), 2,2,3,3,3-pentafluoropropylacrylate (117 mg), ethylene dimethacrylate (663 mg), 2-hydroxyethyl methacrylate (81 mg) and methyl methacrylate (167 mg) are weighed into a 250 ml tall beaker.

[0415] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0416] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0417] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0418] The obtained capsules have an average size of 191 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0419] One part of the obtained sample is further used as is.

[0420] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0421] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0422] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 5.2 m.

[0423] The measured electro-optical parameter V.sub.50 is 80 V, and the measured electro-optical parameter V.sub.90 is 132 V.

Example 20

[0424] LC mixture B-8 (2.00 g), 2,2,3,3,4,4,4-heptafluorobutylacrylate (117 mg), ethylene dimethacrylate (659 mg), 2-hydroxyethyl methacrylate (79 mg) and methyl methacrylate (170 mg) are weighed into a 250 ml tall beaker.

[0425] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0426] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0427] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0428] The obtained capsules have an average size of 147 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0429] One part of the obtained sample is further used as is.

[0430] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0431] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0432] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.9 m.

[0433] The measured electro-optical parameter V.sub.50 is 77.5 V, and the measured electro-optical parameter V.sub.90 is 130 V.

Example 21

[0434] LC mixture B-8 (2.01 g), 1H,1H,2H,2H-perfluorodecylacrylate (113 mg), ethylene dimethacrylate (657 mg), 2-hydroxyethyl methacrylate (75 mg) and methyl methacrylate (171 mg) are weighed into a 250 ml tall beaker.

[0435] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0436] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0437] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0438] The obtained capsules have an average size of 188 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0439] One part of the obtained sample is further used as is.

[0440] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0441] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0442] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 5.3 m.

[0443] The measured electro-optical parameter V.sub.50 is 75 V, and the measured electro-optical parameter V.sub.90 is 115 V.

Example 22

[0444] LC mixture B-8 (1.00 g), pentadecafluorooctanol (111 mg), ethylene dimethacrylate (340 mg) and 2-hydroxyethyl methacrylate (73 mg) are weighed into a 250 ml tall beaker.

[0445] Brij L23 (75 mg) is weighed into a 250 ml conical flask and water (70 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0446] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0447] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0448] The obtained capsules have an average size of 191 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0449] One part of the obtained sample is further used as is.

[0450] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0451] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0452] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 3.7 m.

[0453] The measured electro-optical parameter V.sub.50 is 23 V, and the measured electro-optical parameter V.sub.90 is 53 V.

Example 23

[0454] LC mixture B-8 (1.01 g), 3-tris(trimethylsiloxy) silylpropylmethacrylate (250 mg), ethylene dimethacrylate (300 mg), 2-hydroxyethyl methacrylate (40 mg) and methyl methacrylate (100 mg) are weighed into a 250 ml tall beaker.

[0455] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (75 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0456] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0457] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0458] The obtained capsules have an average size of 124 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0459] One part of the obtained sample is further used as is.

[0460] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0461] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0462] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1.

Example 24

[0463] LC mixture B-8 (2.00 g), trimethylsilyl trifluoroacetate (100 mg), ethylene dimethacrylate (660 mg), 2-hydroxyethyl methacrylate (71 mg) and methyl methacrylate (172 mg) are weighed into a 250 ml tall beaker.

[0464] Brij L23 (300 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0465] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0466] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0467] The obtained capsules have an average size of 271 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0468] One part of the obtained sample is further used as is.

[0469] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0470] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0471] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1.

Example 25

[0472] LC mixture B-8 (2.00 g), tris(trimethylsiloxy)silylpropylmethacrylate (101 mg), ethylene dimethacrylate (659 mg), 2-hydroxyethyl methacrylate (78 mg) and methyl methacrylate (165 mg) are weighed into a 250 ml tall beaker.

[0473] Brij L23 (100 mg) is weighed into a 250 ml conical flask and water (100 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0474] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0475] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (20 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0476] The obtained capsules have an average size of 214 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0477] One part of the obtained sample is further used as is.

[0478] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0479] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0480] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.5 m.

[0481] The measured electro-optical parameter V.sub.50 is 57.5 V, and the measured electro-optical parameter V.sub.90 is 95 V.

Example 26

[0482] LC mixture B-8 (1.00 g), stearylmethacrylate (101 mg), ethylene dimethacrylate (201 mg), 2-hydroxyethyl methacrylate (42 mg) and methyl methacrylate (105 mg) are weighed into a 250 ml tall beaker.

[0483] Brij L23 (50 mg) is weighed into a 250 ml conical flask and water (150 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0484] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0485] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (10 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0486] The obtained capsules have an average size of 208 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0487] One part of the obtained sample is further used as is.

[0488] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0489] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0490] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 3.1 m.

[0491] The measured electro-optical parameter V.sub.50 is 25 V, and the measured electro-optical parameter V.sub.90 is 45.5 V.

Example 27

[0492] LC mixture B-8 (1.00 g), methyl octanoate (73 mg), ethylene dimethacrylate (291 mg), 2-hydroxyethyl methacrylate (46 mg) and methyl methacrylate (98 mg) are weighed into a 250 ml tall beaker.

[0493] Brij L23 (50 mg) is weighed into a 250 ml conical flask and water (150 g) is added. This mixture is then sonicated for 5 to 10 minutes.

[0494] The Brij aqueous surfactant solution is poured directly into the beaker containing the organics. The mixture is turrax mixed for 10 minutes at 10,000 rpm. Once turrax mixing is complete, the crude emulsion is circulated through a high-pressure homogenizer at 30,000 psi for eight minutes.

[0495] The mixture is charged into a flask and fitted with a condenser, and after adding 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) (10 mg) is heated to 70 C. for four hours. The reaction mixture is cooled, filtered, and then size analysis of the material is carried out by Zetasizer instrument.

[0496] The obtained capsules have an average size of 189 nm, as determined by dynamic light scattering (DLS) analysis (Zetasizer).

[0497] One part of the obtained sample is further used as is.

[0498] Another part of the sample is concentrated before further use. This is carried out by centrifuge. A centrifuge tube is filled with the mixture and centrifuged at 6,500 rpm for 10 minutes, the supernatant is collected and put in a new tube and centrifuged at 15,000 rpm for 20 minutes. The resulting pellet is re-dispersed in 1 ml of the supernatant and sampled for testing.

[0499] The obtained nanocapsules exhibit favourable physical and electro-optical characteristics and show suitable switching behaviour in response to an applied voltage.

[0500] A composite system and a film comprising the obtained capsules and the binder are prepared analogous to Example 1. The prepared film has a thickness of 4.3 m.

[0501] The measured electro-optical parameter V.sub.50 is 33 V, and the measured electro-optical parameter V.sub.90 is 64 V.