WE CLAIM:
1. A method of preparing molecular imprinted polymer over a semiconducting layer coated
substrate, comprising steps of:
preparing a porogen solvent comprising in an ratio of 6.75 and 0.75 mL v/v, in a glass
container;
10 sonicate the porogen solvent for about 30-90 seconds,
add a mixture containing template volatile organic compound and about 20-30 µL
monomer into the glass container and sonicate the contents for about 15 minutes;
add about 110-120 µL cross-linker and purge the glass container with nitrogen gas for
about 120 seconds,
15 sonicate the contents for about 10 minutes;
stir the contents for about 10 minutes;
about 10-15 mg of initiator is added to the above content and stirred for about 15 minutes
in a nitrogen atmosphere, to obtain a pre polymer mixture;
semiconducting layer coated substrate is immersed in the pre polymer mixture and
20 purged with nitrogen for about 2 minutes before carefully sealing the glass container,
the sealed glass container is placed in a UV chamber and photopolymerization is carried
out at room temperature at wavelength (λ) of about 350 nm for about 60-100 min using
a 8W UV bulb;
the semiconducting layer coated substrate were removed after about 6-10 min and dried
25 in normal atmospheric conditions;
a thick white layer of molecularly imprinted polymer forms on the surface of the
semiconducting layer coated substrate in about 5-10 seconds;
the molecularly imprinted polymer- semiconducting layer coated substrates are
immersed in a mixture of about 20- 50 µL acetic acid and about 150-200 mL methanol
30 solution, and extracted for about 12 hours using a soxhlet apparatus at about 80-90 ˚C for
the removal of template volatile organic compounds and creation of template-voids;
to obtain molecular imprinted over semiconducting layer coated substrate.
2. The method as claimed in claim 1 wherein the template volatile organic compound is
selected from alcohol, aldehyde, aromatic compounds, styrene, ketone, cyclic ketone,
35 esters, amines, organochlorides, organophosphates, alkanes, alkyne, alkenes.
3. The method as claimed in claim 1 wherein the ratio of template volatile organic
compound, monomer, and cross-linker are kept constant at as n:4:8, wherein ‘n’ ranges
about 1-5.
4. The method as claimed in claim 1 wherein,
the alcohol is selected from 2-phenylethanol, hexenol, linalool, nerolidol, ethanol,
10 methanol, pinocarveol, isopropyl alcohol, pentanol;
the aldehyde is selected from heptanal, nonanal, pentanal, hexanal, acetaldehyde,
formaldehyde, butanal, octanal, octenal, benzaldehyde, phenylacetaldehyde,
cinnamaldehyde, cuminaldehyde, (E,E)‐α‐farnesene‐2(3),9(10)‐diepoxide,
malondialdehyde, hydroxyacetalydehyde, 2-butenal, dimethylbenzaldehyde,
15 phenylpropionaldehyde, perillic aldehyde, methional, hexenal, pentenal;
the aromatic compound is selected from toluene, benzene, styrene, dimethylfuran,
anthracene, dimethylnaphthalene, phenol, xylene, ethylbenzene, cyclohexene,
trimethylbenzene, dichlorobenzene, hydroxytoluene, propylbenzene, phthalates,
benzoates;
20 the styrene is selected from 4-vinylanisole, 4-methoxystyrene, vinylbenzene,
ethenylbenzene, cinnamene, phenylethylene;
the ketone is selected from 2-butanone, pentenone, acetone, pentanone, hexanone,
heptanone, benzophenone, hendecanone, pentadecanone, methyl isobutyl ketone,
heptadecanone; and
25 the cyclic ketone is selected from cyclohexanone, cyclopentanone, cycloheptanone,
cyclooctenone.
5. The method as claimed in claim 1, wherein the semiconducting layer is selected from
polyaniline, carbon nantotubes, activated carbon, graphene oxide, reduced graphene
oxide, class of MXene materials, siloxene, phosphorene, black phosphorus germanene
30 and graphitic carbon nitride, metal oxides, metal chalcogenides, metal phosphides, metal
vanadates, etc their combinations of composite materials and alloys thereof.
6. The method as claimed in claim 1, wherein the substrate is selected from ceramic
alumina, glass slides, fabrics, fluorine doped tin oxide substrates, indium doped tin oxide
substrates, silicon wafers, flexible polymer substrates.
35 7. The method as claimed in claim 1, wherein the porogen solvent is acetonitrile and
toluene, 2-methoxyethanol, methanol, chloroform, tetrahydrofuran (THF),
dichloroethane, N,N-dimethylformamide (DMF) and ionic liquids as 1-Butyl-3
methylimidazolium hexafluorophosphate [BMIM][PF6], 1-Butyl-3 methylimidazolium
tetrafluoroborate [BMIM][BF4], 1-Methyl-3-octyl-imidazolium-hexafluorophosphate
[OMIM][PF6], 1-Hexyl-3-methyl-imidazolium-hexafluorophosphate [HMIM][PF6].
8. The method as claimed in claim 1, wherein the monomer is selected from methacrylic
acid, acrylamide, 4-Vinylpyridine, acrylic acid, 2-Hydroxyethyl Methacrylate (HEMA),
styrene, N,N'-Methylenebisacrylamide (BIS), N-Methacryloyl-(L)-phenylalanine
10 (MAPA), N-Isopropylacrylamide (NIPAM), divinylbenzene (DVB).
9. The method as claimed in claim 1, the crosslinker is selected from ethylene glycol
dimethacrylate, trimethylolpropane trimethacrylate (TRIM), pentaerythritol tetraacrylate
(PETA), N,N'-Methylenebisacrylamide (BIS), 1,4-Butanediol Dimethacrylate
(BDDMA), 1,2-Bis(allyloxy)ethane (BAE).
15 10. The method as claimed in claim 1, the initiator is selected from 2,2'-
azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA), azobis
(2-methylpropionitrile) (AMBN), Benzoyl peroxide, 2,2'-azobis(2,4-
dimethylvaleronitrile) (ADMVN), N,N,N',N'-tetramethylethylenediamine (TEMED).
11. The method as claimed in claim 1, wherein the polyaniline coated substrate for molecular
20 imprinting is prepared by the steps of;
preparing a cationic precursor solution containing about 0.1M aniline in about 0.1M
sulphuric acid;
preparing an anionic precursor solution containing about 0.1M ammonium persulphate
in 0.1M of sulphuric acid; and anionic precursor solution is maintained at 4˚C;
25 substrates were first immersed in the cationic precursor for about 20 seconds,
secondly, substrates were immersed in the anionic precursor for about 15 seconds,
continuing the immersion process in the cationic and the anionic precursor solutions for
about 20 seconds and about 15 seconds alternately for about 50 cycles,
to obtain polyaniline coated substrates;
30 further, the polyaniline coated substrate is immersed in double distilled water to remove
unbound and unreacted anilinium ions; and
the polyaniline coated substrate is dried in vacuum oven at about 80-90˚C for about 24
hours.
12. The method as claimed in claims 1-11, wherein the semiconducting layer coated substrate
35 for molecular imprinting is prepared by UV photopolymerization, bulk polymerization,
electro-polymerization, microwave polymerization, precipitation polymerization,
Reversible addition−fragmentation chain-transfer (RAFT)polymerization, surface
imprinting, lithography imprinting, immobilization imprinting, micro contact imprinting,
and emulsion polymerization.
13. Molecular imprinted polyaniline coated ceramic substrate obtained by the method as
claimed in claims 1-12.
14. A sensor, for sensing volatile organic compounds, comprising;
10 at least two electrodes, and
a molecularly imprinted polymer over a semiconducting layer coated substrate as claimed
in claims 1-12 as sensing element, electrically connected to the two electrodes.
15. The sensor as claimed in claim 14, wherein the distribution of the molecularly imprinted
polymer over semiconducting layer is in the form of a continuous layer with template15 voids, wherein the entire layer is electrically conductive.