SOLUTION-PROCESSABLE HRI OPTICAL FILMS COMPRISING TITANATE NANOPARTICLES
The present invention provides new hybrid materials ( 30 ) comprising titanate nanoparticles ( 1 ), surfactants ( 2 ) and a polymeric matrix ( 3 ) as defined in the claims. The hybrid materials have superior optical properties and may be in the form of a thin film or in the form of micro lenses. The invention further provides for intermediate goods and devices comprising such hybrid materials, and for starting materials to obtain such hybrid materials. The invention also provides for processes of manufacturing said starting materials, said hybrid materials, said intermediate goods, for the use of said starting materials, said hybrid materials, and said intermediate goods.
1 . A solid hybrid material comprising
50-90 wt-% nanoparticles selected from the group of titanates;
1-20 wt-% surfactants selected from the group of monocarboxylic acids comprising a polyether tail and phosphate esters of alkyl ethers;
9-49 wt-% polymeric matrix selected from the group of acrylate polymers, sulfone polymers, epoxy polymers, vinyl polymers, urethane polymers and imide polymers,
characterized in that the nanoparticles are titanates of formula (I),
M x Ti y O z (I),
wherein:
M represents alkaline- or alkaline earth metal,
x represents 0, a real number below 1 or 1,
y represents 1 or, a real number below 1 but excluding 0,
z represents a real number below 1 but excluding 0,
provided that:
z=x/2+2*y if M represents an alkaline metal or
z=x+2*y if M represents an alkaline earth metal or
z=2*y if x=0.
2 . The hybrid material according to claim 1 , wherein the nanoparticles are of a core-shell structure, whereby
the core is a titanate of formula (I) and the shell is Al2O3; and.
3 . The hybrid material according to claim 1 , wherein the titanate is a rutile type TiO2.
4 . The hybrid material according to claim 1 , comprising 75-85 wt-% nanoparticles.
5 . The hybrid material according to claim 1 , wherein said surfactant is a monocarboxylic acid of formula (II),
R(OC n H 2n ) q OCH 2 C(O)OH (II)
wherein
R is C 1-5 -alkyl,
q is an integer from 0 to 5,
n is an integer from 1 to 3.
6 . The hybrid material according to claim 1 , wherein said surfactant is a phosphate ester of an alkyl ether wherein the alkyl ether is of formula (IV),
R 4 O—(C 2 H 4 O) m (C 3 H 6 O) n — (IV),
wherein
R 4 is C 1-10 -alkyl;
m is an integer from 2 to 60;
n is an integer from 2 to 60.
7 . The hybrid material according to claim 1 , wherein the acrylate polymers are obtained from monomers of formula (V-I) or (V-II)
wherein
R 1 independently represents hydrogen or methyl;
X independently represents oxygen or sulphur;
R 2 represents a substituent selected from phenyl, phenyl-C 1-4 alkyl, phenyl-oxy and phenyl-oxy-C 1-4 alkyl;
said phenyl optionally being substituted by 1-3 substituents selected from the group of C 1-4 alkyl, phenyl, halogen, hydroxy.
R 3 represents a substituent selected from phenyl, diphenyl (Ph-Ph), diphenylsulfyl (Ph-S-Ph), diphenyloxy (Ph-O-Ph),
said phenyl optionally being substituted by 1-3 substituents selected from the group of C 1-4 alkyl, phenyl, halogen, hydroxy.
8 . The hybrid material according to claim 1 , wherein the sulfone polymers have repeating units of formula (VI),
wherein
Ar 1 represents phenyl, a phenylether, a phenylthio-ether, a bisphenol, said phenyl optionally being substituted by 1-3 substituents selected from the group of C 1-4 alkyl, phenyl, halogen, hydroxy.
Ar 2 represents phenyl,
said phenyl optionally being substituted by 1-3 substituents selected from the group of C 1-4 alkyl, phenyl, halogen, hydroxy.
9 . The hybrid material according to claim 1 , wherein the vinyl polymer comprises repeating units of formula (VII)
wherein:
R 7 represents hydrogen, C 1-4 alkyl, hydroxy, cyano, 2-pyrrolidone,
R 8 represents hydroxy, cyano, 2-pyrrolidone;
or wherein:
R 7 , R 8 together form a heterocycle,
said heterocycle being selected from 1,3-dioxanes,
said heterocycle optionally being substituted by 1-3 C 1-8 alkyl groups.
10 . The hybrid material according to claim 1 in the form of a thin layer or in the form of micro lenses,
said layer having a thickness of 30 nm-100 μm; and/or
said micro lenses having a diameter of 1-500 μm; and/or
said nanoparticles having a size of 5-30 nm.
11 . An intermediate good comprising a substrate coated with at least one hybrid material layer according to claim 10 .
12 . The intermediate good according to claim 11 , having the following (bottom-up) structure:
Substrate/hybrid material layer/transparent electrode (EL)/active layer stack (AL)-acting as an index matching layer; or
Substrate/hybrid material layer/transparent electrode (EL)/active layer stack (AL) acting as a light extraction layer; or
having the following (bottom-up) structure: Substrate/multiple units of low refractive index layer (LRI) and hybrid material layer or substrate/multiple layers of the hybrid material and low refractive index layer (LRI); or
substrate/hybrid material layer in the form of micro-lenses; or
Substrate/hybrid material layer comprising additional scattering elements (SE)/transparent electrode (EL)/active layer stack (AL) acting as a light extraction layer.
13 . A device comprising the intermediate good according to claim 11 , the device selected from the group consisting of
devices containing a display,
devices that emit light,
fenestration, and
products containing an optical authentication element.
14 . A suspension comprising
0.5-80 wt-% nanoparticles selected from the group of titanates of formula (I),
M x Ti y O z (I),
wherein:
M represents alkaline- or alkaline earth metal,
x represents 0, a real number below 1 or 1,
y represents 1 or, a real number below 1 but excluding 0,
z represents a real number below 1 but excluding 0,
provided that:
z=x/2+2*y if M represents an alkaline metal or
z=x+2*y if M represents an alkaline earth metal or
z=2*y if x=0;
0.01-20 wt-% surfactants wherein said surfactant is a phosphate ester of an alkyl ether wherein the alkyl ether is of formula (IV),
R 4 O—(C 2 H 4 O) m (C 3 H 6 O) n — (IV),
wherein
R 4 is C 1-10 -alkyl;
m is an integer from 2 to 60;
n is an integer from 2 to 60;
0.09-99 wt-% polymeric matrix selected from the group of acrylate polymers, sulfone polymers, epoxy polymers, vinyl polymers, urethane polymers and imide polymers;
0-99 wt-% organic solvent selected from the group of water, alcohols, glycol-ethers, ketones, and aprotic polar solvents.
15 . The suspension of claim 14 , characterized in that
said alcohols are selected from the group of methanol, ethanol, isopropanol, propanol, and butanol;
said glycol-ether is Propoxy-ethanol;
said ketones are selected from acetone and MEK;
said aprotic polar solvents are selected from dimethyl sulfoxide, N-methyl pyrrolidone, dimethyl formamide, dimethyl acetamide.
16 . A method for manufacturing a suspension according to claim 14 , said method comprising the steps of
combining components the organic solvent, nanoparticles and surfactants to obtain a first suspension;
combining components the organic solvent and polymeric matrix to obtain a first solution;
combining said first suspension and said first solution to obtain the suspension.
17 . A method for manufacturing a hybrid material, said method comprising the steps of
providing a suspension according to claim 14 ;
removing the organic solvent, optionally by the aid of reduced pressure and/or heat;
optionally curing the thus obtained material.
18 . A method for manufacturing an intermediate good, said method comprising the steps of
providing a suspension according to claim 14 ;
providing a support material which is optionally coated with one or more layers;
coating/printing said optionally coated support material with said suspension;
optionally providing further coatings on said coated substrate; and/or
optionally post-treatment of said coated support material.
19 . The hybrid material according to claim 2 , wherein the shell amounts to less than 20 wt-% (based on oxide weight) of the whole particle.