Compound having thermotropic liquid crystal structure and polyethylene glycol polymer thereof

Abstract

This invention relates to a compound having a thermotropic liquid crystal structure obtained by modifying a thermotropic liquid crystal molecule with an epoxide functional group, and a polyethylene glycol polymer obtained by ring-opening polymerization of the compound. More specifically, this invention relates to a polyethylene glycol main chain polymer which can be easily molded into a thin film, bulk, or fiber and has high thermal conductivity, and therefore may be used alone as a heat-dissipating polymer or in the form of a composite material.

Description

[Technical Field]

[0001] The present invention relates to a compound having a thermotropic liquid crystal structure obtained by modifying thermotropic liquid crystal molecules with epoxide functional groups, and a polyethylene glycol polymer obtained by ring-opening polymerization of the compound. More specifically, the present invention relates to a polyethylene glycol main chain polymer that can be easily molded into thin films, bulk, or fibers and has high thermal conductivity, and therefore may be used alone as a heat-dissipating polymer or in the form of a composite material. [Background technology]

[0002] Liquid crystalline polymers (LCPs) are polymers (macromolecules) that exhibit a liquid crystalline phase in the molten or solution state, and generally have a structure containing mesogenic units. Thermotropic liquid crystalline polymers (TLCPs) exhibit liquid crystalline behavior in response to temperature changes, and their properties vary significantly depending on the position, shape, and structure of the mesogenic units. Because of their high heat and chemical resistance as well as excellent mechanical properties, they have been applied in fields such as high-performance composites and engineering plastics, and have been the subject of active academic and industrial research.

[0003] However, the thermotropic liquid crystal polymers reported so far have the disadvantage that they must be synthesized and processed at high temperatures or in a solution state of strong acids and organic solvents due to their high melting temperatures and chemical resistance. Most liquid crystal polymers are synthesized using solvents, as described in detail in Patent Documents 1-3: U.S. Patent Nos. 04954606, 05109100, and 04912193. However, in this case, a process of removing the solvent is required after the liquid crystal polymer is produced, and processing in a molten state is difficult. In order to lower the polymerization temperature and processing temperature, methods such as placing bulky molecules in the side chain or introducing long flexible chains into the main chain have been used. Examples of such conventional techniques include Non-Patent Documents 1-6: Journal of Polymer Science Part A: Polymer Chemistry, Vol. 19, (8), 1901 (1981); Macromolecular Chemistry and Physics, Vol. 192, (2), 201 (1991); Polymer Journal, Vol. 17, (1), 105 (1985); Polymer, Vol. 32, (9), 1703 (1991); Polymer Preprint (American Chemical Society), Vol. 27, (1), 369 (1986); Polymer Journal, Vol. 17, (1), 277 (1985); Journal of Polymer Science Part A: Polymer Chemistry, Vol. 21, (11), 3313 (1983). However, at the polymerization temperature and processing temperature of such a structure, performance is reduced to some extent. However, the introduction of new processes and reactants increases costs, and there is a limitation in that additional processes are required to process the produced liquid crystal polymer.

[0004] Therefore, in order to solve the above problems, the present inventors recognized that it was urgent to develop a compound having a thermotropic liquid crystal structure and a polyethylene glycol polymer thereof in order to develop a thermoplastic liquid crystal polymer that is easily molded, and completed the present invention. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent No. 04954606 [Patent Document 2] US Patent No. 05109100 [Patent Document 3] US Patent No. 04912193 [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of Polymer Science Part A: Polymer Chemistry,Vol.19,(8),1901(1981) [Non-patent document 2] Macromolecular Chemistry and Physics,Vol.192,(2),201(1991) [Non-patent document 3] Polymer Journal,Vol.17,(1),105(1985) [Non-patent document 4] Polymer, Vol. 32, (9), 1703 (1991) [Non-Patent Document 5] Polymer Preprint (American Chemical Society), Vol. 27, (1), 369 (1986): Polymer Journal, Vol. 17, (1), 277 (1985) [Non-patent document 6] Journal of Polymer Science Part A: Polymer Chemistry,Vol.21,(11),3313(1983) Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a compound having a thermotropic liquid crystal structure obtained by modifying a thermotropic liquid crystal molecule with an epoxide functional group, and a polyethylene glycol polymer obtained by ring-opening polymerization of the compound.

[0008] Another object of the present invention is to provide a polyethylene glycol polymer that can be easily formed into a thin film, bulk or fiber form and has high thermal conductivity, and therefore can be used as a heat-dissipating polymer or composite material.

[0009] The technical problems that the present invention aims to solve are not limited to the above-mentioned technical problems, and other technical problems not mentioned will also be clearly understood by a person having ordinary skill in the art from the description of the present invention. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a compound having a thermotropic liquid crystal structure in a side chain, represented by the following chemical formula (I).

[0011] [ka]

[0012] (wherein n is an integer of 1 to 30).

[0013] The present invention provides a compound having a thermotropic liquid crystal structure in a side chain, represented by the following chemical formula (II).

[0014] [ka]

[0015] (wherein n is an integer of 1 to 30).

[0016] The present invention provides a polyethylene glycol polymer obtained by ring-opening polymerization of the compound represented by the above chemical formula (I).

[0017] The present invention provides a polyethylene glycol polymer obtained by ring-opening polymerization of the compound represented by the above chemical formula (II).

[0018] The present invention also provides a polyethylene glycol polymer represented by the following chemical formula (III), which is obtained by ring-opening polymerization of a compound represented by the chemical formula (I) or (II).

[0019] [ka]

[0020] (wherein X1 and X2 may be the same or different and are selected from the compounds described in claim 1 or the compounds described in claim 2).

[0021] The polyethylene glycol polymer can be used as a general-purpose material for various electronic components, such as substrates, compounds, adhesives, pads, heat spreaders and heat sinks.

[0022] All references to the compound having a thermotropic liquid crystal structure and its polyethylene glycol polymer are equally applicable unless inconsistent. [Effects of the Invention]

[0023] The novel polyethylene glycol polymer produced by the present invention can be easily molded into thin films, bulk, and fibers, has improved thermal conductivity, and can be used in a variety of electronic components.

[0024] The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will become apparent to those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0025] [Figure 1]1H-NMR spectra of EPCNn (4-(n-(oxiran-2-ylmethoxy)alkyloxy)-4-biphenylcarbonitrile) synthesized according to one embodiment of the present invention, where (a) is the spectrum of EPCN4, (b) is the spectrum of EPCN5, (c) is the spectrum of EPCN6, (d) is the spectrum of EPCN7, (e) is the spectrum of EPCN8, and (f) is the spectrum of EPCN9. [Figure 2] 13C-NMR spectra of the EPCNn, where (a) is the spectrum of EPCN4, (b) is the spectrum of EPCN5, (c) is the spectrum of EPCN6, (d) is the spectrum of EPCN7, (e) is the spectrum of EPCN8, and (f) is the spectrum of EPCN9. [Figure 3] 1H-NMR spectra of P-EPCNn synthesized according to other embodiments of the present invention, where (a) is the spectrum of P-EPCN4, (b) is the spectrum of P-EPCN5, (c) is the spectrum of P-EPCN6, (d) is the spectrum of P-EPCN7, (e) is the spectrum of P-EPCN8, and (f) is the spectrum of P-EPCN9. [Figure 4] 1 is an FT-IR spectrum of the P-EPCNn. [Figure 5] 1 shows the results of gel permeation chromatography (GPC) analysis of the P-EPCNn. [Figure 6] 1 is a phase transition diagram analyzed by a differential scanning calorimeter (DSC). [Figure 7] 1A and 1B are DSC analysis graphs of the EPCNn analyzed at a heating and cooling rate of 2°C / min, where (a) is the spectrum of EPCN4, (b) is the spectrum of EPCN5, (c) is the spectrum of EPCN6, (d) is the spectrum of EPCN7, (e) is the spectrum of EPCN8, and (f) is the graph of EPCN9. [Figure 8] 1 is a polarized optical microscope (POM) image of the EPCNn (scale bar = 50 μm). [Figure 9]1 is a DSC analysis graph of the P-EPCNn analyzed at a heating and cooling rate of 5° C. / min. [Figure 10] This is a POM image of the P-EPCNn (scale bar = 50 μm). [Figure 11] This is a bulk test piece of P-EPCNn manufactured for thermal conductivity evaluation. [Figure 12] 1 is an X-ray diffraction analysis (XRD) graph of P-EPCNn at room temperature. [Figure 13] The optimized molecular structure of the P-EPCNn model compound calculated by density functional theory (DFT) at the B3LYP / 6-31G level is shown. [Figure 14] 1H-NMR spectra of OMPBn (4-(oxiran-2-ylmethoxy)phenyl 4-alkoxybenzoates) synthesized according to another embodiment of the present invention, where (a) is the spectrum of OMPB4, (b) is the spectrum of OMPB6, (c) is the spectrum of OMPB8, and (d) is the spectrum of OMPB10. [Figure 15] 13C-NMR spectra of the OMPBn, where (a) is the spectrum of OMPB4, (b) is the spectrum of OMPB6, (c) is the spectrum of OMPB8, and (d) is the spectrum of OMPB10. [Figure 16] 1H-NMR spectra of P-OMPBn synthesized according to another embodiment of the present invention, where (a) is the spectrum of P-OMPB4, (b) is the spectrum of P-OMPB6, (c) is the spectrum of P-OMPB8, and (d) is the spectrum of P-OMPB10. DETAILED DESCRIPTION OF THE INVENTION

[0026] The terms used in this specification are currently commonly used and general terms that are selected as much as possible while taking into consideration the functions of the present invention, but they may vary depending on the intentions of those skilled in the art, precedents, or the emergence of new technologies. In addition, in certain cases, the applicant may arbitrarily select terms, and in such cases, their meanings will be described in detail in the description of the invention. Therefore, the terms used in this specification are defined based on the meanings that the terms have and the overall content of the present invention, rather than simply by their names.

[0027] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0028] Numerical ranges are inclusive of the numerical values ​​defined in the range. Every maximum numerical limitation given herein includes every lower numerical limitation, as if such lower numerical limitation were expressly stated. Every minimum numerical limitation given herein includes every higher numerical limitation, as if such higher numerical limitation were expressly stated. Every numerical limitation given herein includes every finer numerical range within a broader numerical range, as if such narrower numerical limitations were expressly stated.

[0029] The present invention will be described in detail below.

[0030] The present invention provides a compound having a thermotropic liquid crystal structure in a side chain, represented by the following chemical formula (I).

[0031] [ka]

[0032] (wherein n is an integer of 1 to 30).

[0033] The compound of formula (I) can be synthesized by reacting 4-hydroxy-4-biphenylcarbonitrile as a starting material with a dibromoalkane to give 4-(4-bromoalkoxy)-4-biphenylcarbonitrile (BRCNn), which can then be synthesized by reacting 4-(4-bromoalkoxy)-4-biphenylcarbonitrile with glycidol again as a starting material.

[0034] The compound may be 4-(n-(oxiran-2-ylmethoxy)alkyloxy)-4-biphenylcarbonitrile.

[0035] The preparation of the compound of formula (I) may be carried out under basic conditions, for example in the presence of sodium hydroxide.

[0036] In preparing the compound of formula (I), dimethylformamide (DMF), N-methylpyrrolidone (NMP), N,N'-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), meta-cresol (m-cresol), or a mixture thereof can be used as a solvent.

[0037] The reaction for producing the compound of formula (I) may be carried out at a temperature of 20 to 45°C, preferably 30 to 45°C.

[0038] The preparation time of the compound of formula (I) may be 36 to 48 hours, preferably 36 to 42 hours.

[0039] The present invention provides a compound having a thermotropic liquid crystal structure in a side chain, represented by the following chemical formula (II).

[0040] [ka]

[0041] (wherein n is an integer of 1 to 30).

[0042] The compound of formula (II) can be synthesized by reacting 4-(alkoxy)benzoic acid as a starting material with hydroquinone to synthesize 4-hydroxyphenyl-4-alkoxybenzoate (HPBn), and then reacting the 4-hydroxyphenyl-4-alkoxybenzoate with epichlorohydrin to synthesize the compound.

[0043] The compound may be 4-(oxiran-2-ylmethoxy)phenyl-4-butoxybenzoate.

[0044] The preparation of the compound of formula (II) may be carried out under basic conditions, for example in the presence of sodium hydroxide.

[0045] The reaction for producing the compound of formula (II) may be carried out at a temperature of 65 to 95°C, preferably 70 to 85°C.

[0046] The preparation time of the compound of the formula (II) may be 0.5 to 4 hours, preferably 0.5 to 2 hours.

[0047] The present invention provides a polyethylene glycol polymer obtained by ring-opening polymerization of a compound having a thermotropic liquid crystal structure in its side chain, represented by the above chemical formula (I).

[0048] The present invention provides a polyethylene glycol polymer obtained by ring-opening polymerization of a compound having a thermotropic liquid crystal structure in its side chain, represented by the above chemical formula (II).

[0049] The present invention also provides a polyethylene glycol polymer represented by the following chemical formula (III), which is obtained by ring-opening polymerization of a compound having a thermotropic liquid crystal structure represented by the chemical formula (I) or (II):

[0050] The ring-opening polymerization may be any one selected from anionic ring-opening polymerization, cationic ring-opening polymerization, and radical ring-opening polymerization, but is not limited thereto.

[0051] [ka]

[0052] (wherein X1 and X2 may be the same or different and are selected from the compounds described in claim 1 or the compounds described in claim 2).

[0053] The compound of formula (III) may be a homopolymer or a copolymer.

[0054] The ring-opening polymerization may be carried out in the presence of an initiator, and the initiator may be a metal alkoxide such as potassium tert-butoxide, lithium tert-butoxide, sodium tert-butoxide, potassium ethoxide, aluminum butoxide, or aluminum isopropoxide, or any initiator known to those skilled in the art may be used.

[0055] The ring-opening polymerization may be carried out in the presence of a catalyst, which may be a catalyst such as 18-crown-6-ether, 15-crown-5-ether, dibenzo-18-crown-6, dicyclohexyl-18-crown-6, and tetramethylammonium chloride (TMAC), or any catalyst known to those skilled in the art may be used.

[0056] The ring-opening polymerization may be carried out in the presence of a solvent, and the solvent may be a solvent such as toluene, cyclohexane, hexane, heptane, xylene, or ethylbenzene, or any solvent known to those skilled in the art may be used.

[0057] In the ring-opening polymerization, the initiator may be contained in an amount of 1 to 45 parts by weight, preferably 5 to 45 parts by weight, and more preferably 10 to 45 parts by weight, relative to 100 parts by weight of all the monomers.

[0058] If the amount of the initiator added is less than 1 part by weight, the problem of non-polymerization may occur, and if the amount of the initiator added is more than 45 parts by weight, the problem of low molecular weight polymer formation may occur.

[0059] In the ring-opening polymerization, the catalyst may be contained in an amount of 0.1 to 15 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 15 parts by weight, relative to 100 parts by weight of all monomers.

[0060] If the amount of the catalyst added is less than 0.1 parts by weight, problems of non-polymerization or a decrease in reaction rate may occur, and if the amount of the catalyst added exceeds 15 parts by weight, problems of the production of low molecular weight polymers may occur.

[0061] The ring-opening polymerization may be carried out at a temperature of 50 to 70°C, preferably at a temperature of 55 to 65°C.

[0062] The ring-opening polymerization may be carried out for 72 to 84 hours, preferably 72 to 80 hours.

[0063] The ring-opening polymerization may be carried out by displacement under non-reactive gas conditions, and the non-reactive gas may be helium, argon or nitrogen, preferably argon or nitrogen, most preferably argon.

[0064] After the ring-opening polymerization, the polymerization solution can be precipitated in alcohol.

[0065] The alcohol may be an alcohol such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, and heptanol, and any alcohol known to those skilled in the art may be used.

[0066] The precipitation may be carried out 2 to 5 times, preferably 2 to 4 times.

[0067] The polyethylene glycol polymer of the chemical formula (III) may have a thermal conductivity of 0.30 (W / mK) or more, for example, 0.30 to 0.45 (W / mK).

[0068] The polyethylene glycol polymer of the chemical formula (III) may have a glass transition temperature of 10°C or higher, for example, 10 to 60°C, preferably 10 to 55°C.

[0069] The polyethylene glycol polymer of the chemical formula (III) may have a melting point of 85°C or higher, for example, 85 to 200°C, preferably 88 to 200°C.

[0070] The polyethylene glycol polymers of the present invention may be used in the electronics industry, for example, in substrates, compounds, adhesives, pads, heat spreaders, and heat sinks. <Example>

[0071] The present invention will be described in detail below with reference to examples to aid in understanding the present invention. However, the following examples are merely illustrative of the contents of the present invention, and the scope of the present invention is not limited by the following examples. The examples of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0072] <Substances used and analytical methods> 1.Substances used 4-Hydroxy-4-biphenylcarbonitrile and six dibromoalkanes were purchased from TCI (Japan). Potassium carbonate, anhydrous toluene, 18-crown-6, and potassium tert-butoxide were obtained from Alfa Aesar (USA). General chemicals such as magnesium sulfate and sodium hydroxide, as well as general organic solvents, were purchased from Duksan and Daejung Chemicals (Korea). Anhydrous toluene, anhydrous acetone, anhydrous DMF, and silica gel were purchased from Wako Pure Chemical (Japan). All chemicals were used without further purification, and all reactions were performed under an argon (Ar) atmosphere.

[0073] 2.Analysis method The chemical structure of the synthesized substance was analyzed at the Instrumental Analysis Center of Kyungpook National University using a nuclear magnetic resonance spectrometer (NMR, AVANCE III 500, Bruker) with CDCL3 or DMSO-d6 as the solvent. 1 H NMR (500 MHz) and 13 The carbon monoxide content was determined by C NMR (125 MHz), and tetramethylsilane (TMS) was used as an internal standard.

[0074] To examine the functional groups of the synthesized polymers, Fourier transform infrared spectroscopy (FT-IR, FT / IR-4100, Jasco) was performed, and high-resolution mass spectrometry (HRMS) was obtained from the Korea Institute for Basic Science, Daegu Center.

[0075] Thermal properties, including phase transition behavior, were investigated using differential scanning calorimeters (DSC, Q2000, TA Instruments, and DSC4000, PerkinElmer) under a N2 atmosphere. Approximately 5.0 mg of sample was used for DSC measurements, and an empty aluminum pan was used as a reference. The heating and cooling rates for DSC measurements were 2°C or 5°C per minute, and no critical differences were confirmed by at least two repeated cycle measurements.

[0076] The mesomorphic properties were analyzed using a polarized optical microscope (POM, BX53M, Olympus) with a Linkam stage (LTS420). For POM observation, a 20 μm-thick liquid crystal (LC) cell fabricated as follows was used.

[0077] Glass plate (2.5 x 2.5 cm) 2 ) and a cleaned glass plate (7.0 × 5.0 cm 2 ) was ultrasonically cleaned in three successive steps using water, distilled water, and 2-propanol with 1.0 wt% neutral detergent. After drying the plate surface at 120°C for 1 hour, a pair of glass plates was assembled with spacers and epoxy adhesive to form an LC cell with a cell gap of 20 μm. The LC material was injected into the cell in its LC state by capillary force.

[0078] The molecular weight of the polymer was measured by gel permeation chromatography (GPC, AS-4050, Jasco) using 50 mM LiBr eluent and dimethylformamide (DMF) and corrected with polystyrene (PS).

[0079] Thermal conductivity (TC) was measured using a TC measurement system (TPS3500S, Hot Disk) on a circular specimen (diameter: 10 mm, thickness: approximately 3 mm).

[0080] The microstructure of the polymer in bulk was investigated using an X-ray diffractometer (XRD, Empyrean, Malvern Panalytical).

[0081] Example 1: Synthesis of EPCNn: 4-(n-(oxiran-2-ylmethoxy)alkyloxy)-4-biphenylcarbonitrile) Monomer

[0082] The following reaction scheme 1 shows the synthesis process of epoxide monomer EPCNn, which has a cyanobiphenyl side chain with a thermotropic liquid crystal structure. BRCNn is synthesized from 4-hydroxy-4-biphenylcarbonitrile as a starting material by reacting it with dibromoalkane, and then EPCNn is obtained by reacting it with glycidol.

[0083] [ka]

[0084] 1) Synthesis of BRCNn: 4-(4-bromoalkoxy)-4-biphenylcarbonitrile A) n=4 (BRCN4) Potassium carbonate (3.19 g, 23.1 mmol) and 4-hydroxy-4-biphenylcarbonitrile (3.00 g, 15.4 mmol) were placed in a three-neck round-bottom flask. After purging with argon, 45 mL of acetone was added to dissolve the solute. 1,4-Dibromobutane (2.80 mL, 23.1 mmol) was then added to the flask and stirred at 60 °C for 24 hours. The resulting substance was extracted with diethyl ether, and the organic phase was dried over magnesium sulfate. It was then purified by silica column chromatography using a hexane:ethyl acetate (8:1 volume ratio) solution as a developing solvent. The yield was 57%. 1 H NMR (500MHz, CDCl3): δ=7.70(d,J=8.5Hz,2H),7.65(d,J=8.5Hz,2H),7.51(d,J=9.0Hz,2H),7.00(d, J=8.5Hz,2H),4.07(t,J=6.0Hz,2H),3.52(t,J=6.5Hz,2H),2.13-2.08(m,2H),2.01-1.96(m,2H)ppm.

[0085] B) n=5(BRCN5) This was synthesized using the same procedure as A) except that 1,5-dibromopentane was used. The yield was 42%. 1 H NMR(500MHz,CDCl3):δ=7.70(d,J=8.5Hz,2H),7.65(d,J=8.5Hz,2H),7.54(d,J=9.0Hz,2H),7.00(d,J=8.5Hz, 2H),4.04(t,J=6.5Hz,2H),3.47(t,J=7.0Hz,2H),1.99-1.93(m,2H),1.88-1.83(m,2H),1.69-1.64(m,2H)ppm.

[0086] C)n=6(BRCN6) This was synthesized using the same procedure as A) except that 1,6-dibromohexane was used. The yield was 53%. 1H NMR(500MHz,CDCl3):δ=7.70(d,J=9.0Hz,2H),7.65(d,J=8.5Hz,2H),7.54(d,J=9.0Hz,2H),7.00(d,J=8.5Hz, 2H),4.03(t,J=6.0Hz,2H),3.45(t,J=7.0Hz,2H),1.93-1.90(m,2H),1.85-1.82(m,2H),1.53-1.52(m,4H)ppm

[0087] D) n=7(BRCN7) This was synthesized using the same procedure as A) except that 1,7-dibromoheptane was used. The yield was 24%. 1 H NMR (500MHz, CDCl3): δ=7.63(d,J=8.5Hz,2H),7.58(d,J=8.5Hz,2H),7.47(d,J=9.0Hz,2H),6.93(d, J=9.0Hz,2H),3.95(t,J=6.5Hz,2H),3.37(t,J=6.5Hz,2H),1.91-1.79(m,4H),1.51-1.40(m,6H)ppm.

[0088] E)n=8(BRCN8) This was synthesized using the same procedure as A) except that 1,8-dibromooctane was used. The yield was 34%. 1 H NMR (500MHz, CDCl3): δ=7.70(d,J=9.0Hz,2H),7.65(d,J=8.5Hz,2H),7.54(d,J=9.0Hz,2H),7.00(d, J=9.0Hz,2H),4.02(t,J=6.5Hz,2H),3.43(t,J=6.5Hz,2H),1.90-1.79(m,4H),1.53-1.34(m,8H)ppm.

[0089] F)n=9(BRCN9) This was synthesized using the same procedure as A) except that 1,9-dibromononane was used. The yield was 51%. 1H NMR (500MHz, CDCl3): δ=7.70(d,J=8.5Hz,2H),7.50(d,J=8.5Hz,2H),7.54(d,J=9.0Hz,2H),7.00(d,J =8.5Hz,2H),4.02(t,J=6.5Hz,2H),3.43(t,J=6.5Hz,2H),1.89-1.78(m,4H),1.51-1.31(m,10H)ppm.

[0090] 2) Synthesis of EPCNn: 4-(n-(oxiran-2-ylmethoxy)alkyloxy)-4-biphenylcarbonitrile G)n=4(EPCN4) The BRCN4 (1.94 g, 5.87 mmol) and sodium hydroxide (0.352 g, 8.81 mmol) were placed in a three-necked round-bottom flask, and after replacing the atmosphere with argon, glycidol (1.00 ml, 11.6 mmol) and 35.0 ml of dimethylformamide were added. The reaction was carried out at 30°C for 3 days, and the resulting substance was extracted with ethyl acetate, dried over magnesium sulfate, and then purified by silica column chromatography using a hexane:ethyl acetate solution in a volume ratio of 4:1 as a developing solvent. The yield was 51%. The substance was identified by 1 H NMR, 13 The analysis was performed using C NMR and high-resolution mass spectrometry, and the results are as follows: 1 H NMR(500MHz,CDCl3):δ=7.70(d,J=8.5Hz,2H),7.65(d,J=8.5Hz,2H),7.53(d,J=8.5Hz,2H),6.99(d,J=8.5Hz,2H),4.04(t,J=6.5Hz,2H),3.77(dd,J= 11.5,3Hz,1H),3.60(m,2H),3.39(dd,J=11.5,6Hz,1H),3.16(m,1H),2.80 (dd,J=5,4.5Hz,1H),2.61(dd,J=5,3Hz,1H),1.90(m,2H),1.81(m,2H)ppm. 13C NMR(125MHz,CDCl3):δ=159.7,145.3,132.6,131.4,128.3,127.1,119.1,115.1,110.1,71.5,71.1,67.8,50.9,44.2,26.3,26.0ppm.HRMS(+EI):calcd for[C 20 H 21 NO3] + : m / z 323.1521; found: m / z 323.1522 (Figure 1(a) and Figure 2(a)).

[0091] H)n=5(EPCN5) This was synthesized in the same manner as in G) except that BRCN5 was used. The yield was 35%. 1 H NMR (500MHz, CDCl3): δ=7.70(d,J=8.5Hz,2H),7.65(d,J=8.5Hz,2H),7.53(d,J=9Hz,2H),6.99(d,J=9Hz,2H),4.02(t,J=6Hz,2H),3.77(dd,J=11.5,3Hz ,1H),3.55(m,2H),3.40(dd,J=11.5,6Hz,1H),3.15(m,1H),2.80(dd,J=5,4H z,1H),2.62(dd,J=5,2.5Hz,1H),1.84(m,2H),1.68(m,2H),1.56(m,2H)ppm. 13 C NMR (125MHz, CDCl3): δ=159.7,145.3,132.6,131.3,128.3,127.1,119.1,115. 1,110.0,71.6,71.4,68.0,50.9,44.3,29.5,29.0,22.7ppm.HRMS(+EI):calcd for[C 21 H 23 NO3] + : m / z 337.1678; found: m / z 337.1680 (Figure 1(b) and Figure 2(b)).

[0092] I)n=6(EPCN6) This was synthesized in the same manner as in G), except that BRCN6 was used. The yield was 47%. 11H NMR (500 MHz, CDCl3): δ = 7.70 (d, J = 8.5 Hz, 2H), 7.65 (d, J = 8 Hz, 2H), 7.53 (d, J = 8.5 Hz, 2H), 6.99 (d, J = 9 Hz, 2H), 4.01 (t, J = 6.5 Hz, 2H), 3.74 (dd, J = 11.5, 3 Hz, 1H), 3.52 (m, 2H), 3.38 (dd, J = 11.5, 6 Hz, 1H), 3.15 (m, 1H), 2.80 (dd, J = 5, 4.5 Hz, 1H), 2.61 (dd, J = 5, 3 Hz, 1H), 1.82 (m, 2H), 1.64 (m, 2H), 1.50 (m, 4H) ppm. 13 13C NMR (125 MHz, CDCl3): δ = 159.8, 145.3, 132.6, 131.3, 128.3, 127.1, 119.1, 115.1, 110.0, 71.5, 71.5, 68.0, 50.9, 44.3, 29.6, 29.7, 25.9 ppm. HRMS (+EI): calcd for 22 H 25 NO3] + : m / z 351.1834; found: m / z 351.1832 (Figure 1(c) and Figure 2(c)).

[0093] J)n=7(EPCN7) Synthesized in the same procedure as G) except using the above BRCN7. The yield was 33%. 1 1H NMR (500 MHz, CDCl3): δ = 7.70 (d, J = 9 Hz, 2H), 7.65 (d, J = 8.5 Hz, 2H), 7.53 (d, J = 9 Hz, 2H), 6.99 (d, J = 8.5 Hz, 2H), 4.00 (t, J = 6.5 Hz, 2H), 3.73 (dd, J = 11.5, 3 Hz, 1H), 3.51 (m, 2H), 3.39 (dd, J = 11.5, 5.5 Hz, 1H), 3.14 (m, 1H), 2.80 (dd, J = 5, 4 Hz, 1H), 2.61 (dd, J = 5, 2.5 Hz, 1H), 1.81 (m, 2H), 1.61 (m, 2H), 1.50 (m, 2H), 1.39 (m, 4H) ppm. 13C NMR(125MHz,CDCl3):δ= 159.8,145.3,132.6,131.3,128.3,127.1,119.1,115.1,110.0,71.6,71.5,68.1,50.9,44.3,29.6,29.2,29.1,26.0,25.9ppm.HRMS(+EI):calcd for[C 23 H 27 NO3] + : m / z 365.1991; found: m / z 365.1992 (Figure 1(d) and Figure 2(d)).

[0094] K)n=8(EPCN8) This was synthesized in the same manner as in G) except that BRCN8 was used. The yield was 44%. 1 H NMR (500MHz, CDCl3): δ=7.70(d,J=8Hz,2H),7.65(d,J=8.5Hz,2H),7.53(d,J=8. 5Hz,2H),6.99(d,J=9Hz,2H),4.00(t,J=6.5Hz,2H),3.73(dd,J=11.5,3Hz,1H),3 .50(m,2H),3.39(dd,J=11.5,5.5Hz,1H),3.15(m,1H),2.80(dd,J=5,4.5Hz,1H) ,2.61(dd,J=5,3Hz,1H),1.80(m,2H),1.60(m,2H),1.47(m,2H),1.36(m,6H)ppm. 13 C NMR(125MHz,CDCl3):δ=159.8,145.3,132.6,131.3,128.3,127.1,119.1,115.1,110.0 ,71.7,71.5,68.1,50.9,44.3,29.7,29.4,29.3,29.2,26.0,25.9ppm.HRMS(+EI):calcd for[C 24 H 29 NO3] + : m / z 379.2147; found: m / z 379.2145 (Figure 1(e) and Figure 2(e)).

[0095] L)n=9(EPCN9) This was synthesized in the same manner as in G) except that BRCN9 was used. The yield was 38%. 1 H NMR (500MHz, CDCl3): δ=7.70(d,J=8.5Hz,2H),7.65(d,J=8.5Hz,2H),7.53(d,J= 9Hz,2H),6.99(d,J=8.5Hz,2H),4.00(t,J=6.5Hz,2H),3.72(dd,J=11.5,3Hz,1H) ,3.50(m,2H),3.37(dd,J=11.5,6Hz,1H),3.15(m,1H),2.79(dd,J=5,4Hz,1H),2 .61(dd,J=5,2.5Hz,1H),1.80(m,2H),1.59(m,2H),1.47(m,2H),1.33(m,8H)ppm. 13 C NMR(125MHz,CDCl3):δ=159.8,145.3,132.6,131.3,128.3,127.1,119.1,115.1,110.0,71 .7,71.5,68.2,50.9,44.3,29.7,29.5,29.4,29.3,29.2,26.1,26.0ppm.HRMS(+EI):calcd for[C 25 H 31 NO3] + : m / z 393.2304; found: m / z 393.2304 (Figure 1(f) and Figure 2(f)).

[0096] Example 2: Synthesis of EPCNn polymer (P-EPCNn) The following reaction scheme 2 shows the synthesis process of P-EPCNn, a polyethylene glycol derivative having a liquid crystalline cyanobiphenyl in the side chain. As shown in the following reaction scheme 2, it was synthesized by anionic ring-opening polymerization of epoxide monomer EPCNn to form a polyethylene glycol main chain.

[0097] [ka]

[0098] A) n = 4 (P-EPCN4) EPCN4 (1.34 mmol), potassium tert-butoxide (50.5 mg, 500 μmol), and 18-crown-6 (28.0 mg, 100 μmol) were placed in a Schlenk tube, and after replacing the atmosphere with argon, 3 mL of toluene was added. The polymerization solution was stirred at 60 °C for 3 days, then poured into 50 mL of methanol for precipitation, and the precipitate was collected. The precipitation process was repeated twice, yielding a pale yellow solid in 61% yield. 1 H NMR (500MHz, CDCl3): δ=7.63-7.45(m,6H),6.93-6.92(m,2H),3.98-3.95(m,2H),3.76-3.39(m,7H),1.83-1.40(m, 4H),1.09(s,terminal-9H)ppm.FT-IR(ATR):3365,3184,2940,2867,2225,1651,1603,1495,1250,1110,822,770cm -1( Figure 3(a)).

[0099] B) n = 5 (P-EPCN5) This was synthesized in the same manner as in A) except that EPCN5 was used. The yield was 72%. 1 H NMR(500MHz,CDCl3):δ=7.67-7.66(m,2H),7.62-7.61(m,2H),7.50-7.49(m,2H),6.96-6.95(m,2H),3.98-3.97(m,2H),3.80-3.41(m, 7H),1.80-1.42(m,6H),1.11(s,terminal-9H)ppm.FT-IR(ATR):3360,3181,2937,2865,2224,1657,1602,1494,1248,1110,821,771cm -1 (Figure 3(b)).

[0100] C) n = 6 (P-EPCN6) This was synthesized in the same manner as in A) except that EPCN6 was used. The yield was 71%. 1H NMR (500MHz, CDCl3): δ=7.66(s,2H),7.62-7.61(m,2H),7.50-7.49(m,2H),6.96-6.95(m,2H),3.98-3.97(m,2H),3.77-3.41(m,7H) ,1.80-1.42(m,8H),1.11(s,terminal-9H)ppm.FT-IR(ATR):3362,3176,2935,2863,2224,1656,1603,1495,1250,1111,822,770cm -1 (Figure 3(c)).

[0101] D) n = 7 (P-EPCN7) This was synthesized in the same manner as in A) except that EPCN7 was used. The yield was 71%. 1 H NMR (500MHz, CDCl3): δ=7.66(s,2H),7.62(s,2H),7.50(s,2H),6.97(s,2H),3.98-3.97(m,2H),3.78-3.43(m,7H),1.79-1.37(m, 10H),1.11(s,terminal-9H)ppm.FT-IR(ATR):3675,3364,3184,2989,2990,2225,1653,1603,1495,1393,1249,1065,822,771cm -1 (Figure 3(d)).

[0102] E)n=8(P-EPCN8) This was synthesized in the same manner as in A) except that EPCN8 was used. The yield was 71%. 1 H NMR(500MHz,CDCl3):δ=7.68-7.67(m,2H),7.63-7.62(m,2H),7.52-7.50(m,2H),6.97-6.96(m,2H),3.98-3.96(m,2H),3.74-3.42(m,7H),1. 79-1.34(m,12H),1.11(s,terminal-9H)ppm.FT-IR(ATR):3675,3364,3185,2930,2859,2224,1652,1603,1495,1250,1111,1077,822,770cm -1(Figure 3(e)).

[0103] F)n=9(P-EPCN9) This was synthesized in the same manner as in A) except that EPCN9 was used. The yield was 71%. 1 H NMR(500MHz,CDCl3):δ=7.68-7.67(m,2H),7.65-7.62(m,2H),7.53-7.51(m,2H),6.98-6.97(m,2H),4.00-3.94(m,2H),3.73-3.41(m,7H),1.79 -1.31(m,14H),1.11(s,terminal-9H)ppm.FT-IR(ATR):3675,3380,3192,2931,2854,2225,1650,1603,1495,1394,1251,1110,1077,823,770cm -1 (Fig. 3(f)).

[0104] Referring to FIG. 4, which shows the FT-IR (Fourier transform infrared) spectrum of the P-EPCNn obtained above, it can be seen that the polyethylene glycol (PEG) backbone polymer was synthesized without leaving any epoxide moiety.

[0105] Table 1 below shows the molecular weight of the P-EPCNn obtained above (FIG. 5), and Table 2 below shows the physical properties of the P-EPCNn.

[0106] [Table 1]

[0107] [Table 2]

[0108] The mesophase and phase transition behavior of the material synthesized as described above were analyzed using a differential scanning calorimeter (DSC) and a polarized optical microscope (POM). As shown in Figures 6 to 10, the phase transition behavior observed in the POM showed the same tendency as the DSC results.

[0109] In the monomeric state, the cyanobiphenyl (CB) structure, a typical thermotropic liquid crystal, forms a transparent liquid crystal phase, although some variability was observed depending on the length of the alkyl linking chain. Specifically, as shown in Figure 7, EPCN5, EPCN6, and EPCN8 exhibited enantiotropic mesophases, while EPCN4, EPCN7, and EPCN9 exhibited monotropic liquid crystals upon cooling. EPCN5 exhibited a relatively broad liquid crystal phase (LC phase) below room temperature, whereas EPCN7 exhibited a significantly narrower mesophase above room temperature. Furthermore, POM observations confirmed that the liquid crystal phase of all monomers was a transparent nematic phase. Overall, the EPCN series was a thermotropic LC with a mesophase in the temperature range of approximately 40°C to 15°C, slightly above room temperature.

[0110] 9, it can be seen that P-EPCNn exhibits phase transition behavior independent of EPCNn in the polymer (high molecular weight) state. Because a polyethylene glycol (PEG) main chain polymer is formed while maintaining the monomer structure, some tendency in the polymer structure was expected, but the results did not show this.

[0111] Except for P-EPCN4, the glass transition temperature (T g ) was observed between 15 and 20°C, which was slightly lower than room temperature, while the T g was observed at 32.6°C, slightly higher than room temperature.

[0112] Melting temperature (T m), the endothermic peaks of P-EPCN5, P-EPCN7, and P-EPCN9, which have odd numbers of interchain spacers, were observed below 100 °C, whereas the endothermic peaks of P-EPCN4, P-EPCN6, and P-EPCN8, which have even numbers of interchain spacers, were observed above 100 °C.

[0113] Unlike the glass transition behavior, certain trends were observed in the melting behavior related to the odd-even effect, which is believed to be related to the formation of alkyl spacer crystalline structures.

[0114] As shown in Tables 1 and 2, P-EPCNn exhibited a clear odd-even effect due to the alkyl spacer. This result is believed to be due to the relative orientation of the mesogenic groups affecting the average shape of the side chains and the equivalent weight of the spacer moiety. In the odd-numbered members, the mesogenic units were perpendicular to the backbone, whereas in the even-numbered members, the mesogenic units were restricted to being positioned at specific angles relative to the backbone. Furthermore, the effect of chain length was significant in the odd-numbered members but not in the even-numbered members. These results suggest that even-numbered linkers, restricted by symmetry effects, have greater angular restriction than chain length.

[0115] Overall, the phase transition temperature of P-EPCN4 was slightly higher than that of other polymers (polymers), and the behavior of the other polymers (polymers) was similar. This is thought to be the result of similar adjustment of the molecular weight and degree of polymerization. Since P-EPCNn was a side-chain liquid crystal polymer (SCLCP) rather than a main-chain type, it is presumed that similar phase transition behavior was observed when the linker length that allows interaction was secured to a certain extent. In particular, T m At temperatures above this, a highly viscous, translucent liquid phase is obtained, and T m The opaque solid phase remained below this temperature.

[0116] To evaluate the thermal conductivity (TC), P-EPCNn bulk specimens were prepared by a melting process. m Each sample was melted at the above temperatures and processed into circular chips with a diameter of 1 cm. The thickness varied depending on the amount of sample, but was fixed at approximately 3 mm (Figure 11). The color of the sample after polymerization was completely white, but changed to pale yellow after processing. This is thought to be due to the interaction of the aromatic components. The TC values ​​can be confirmed from Table 2 above.

[0117] Liquid crystal polymers exhibit anisotropic thermal conductivity because their molecules are aligned in a specific direction. In particular, this molecular orientation improves thermal conductivity by reducing phonon scattering due to uniform alignment in a specific direction, and induces different phonon paths depending on the dimension. However, in this experiment, P-EPCNn did not exhibit dimensional anisotropy because no alignment process was performed during the bulk material preparation process. It is expected to exhibit anisotropy on a microscale but isotropy on a macroscale. Nevertheless, all P-EPCNn except P-EPCN4 exhibited a thermal conductivity of 0.42-0.46 Wm -1 K -1 P-EPCN4 showed a significantly higher TC of 0.32 Wm -1 K -1 The TC was about 0.2-0.3 Wm, which is also high considering the value of PEG. For PEG, whose main chain is similar to that of P-EPCNn, slight changes were observed depending on the molecular weight, but the TC was about 0.2-0.3 Wm -1 K -1 Therefore, it is clear that P-EPCNn has a two-fold higher TC due to the interaction of the cyanobiphenyl mesogens in the pendant chains.

[0118] To confirm the intermolecular interactions, we analyzed the crystalline structure of the bulk specimens by X-ray diffraction (XRD). As shown in Figure 12, the diffraction curves showed three distinct peaks: a low-angle peak below 10° 2θ (shown in light yellow), a peak near 20° (shown in light blue), and a peak above 25° (shown in light green). Despite the difference in molecular weight, pure linear PEG, a highly crystalline semicrystalline polymer, showed two distinct peaks around 20° and multiple peaks above 25°, suggesting that P-EPCNn is a SCLCP with a similar backbone structure. In the case of P-EPCN6–P-EPCN8, the peaks originating from the PEG backbone were clearly identified near 2θ = 20°, while the peaks elsewhere showed similar, though vague, shapes.

[0119] However, the sharpness of the peaks, which represents the interfacial distance of the mesogens due to the random LC alignment, was different in the PEG sample. However, the sharpness of the peaks was different for the PEG sample, which was assumed to represent the interplanar spacing of mesogens due to random LC ordering. This broad peak was approximately 4–5 Å, corresponding to a typical intermesogen spacing. In particular, clear evidence of mesogen self-organization was observed in the low-angle region below 10°. Depending on the chain spacer length, slight differences were observed between the peak at approximately 4° and the peak at 7–8°. The peak at approximately 4° corresponds to 20–25 Å, while the peak at 7–8° corresponds to 11–13 Å, indicating relatively long-range ordering.

[0120] Long-range interactions were observed in P-EPCN5 to P-EPCN9, but weak interactions were observed in P-EPCN4, which exhibited a liquid crystalline phase (LC phase) at room temperature. As a result, the alignment quality of P-EPCN4 was deteriorated by the interactions, and its thermal conductivity was lower than that of the other samples. Furthermore, optical observation confirmed that the LC phase of all P-EPCNn was a nematic phase, but structural analysis suggested that P-EPCN5 to P-EPCN9 were not in a smectic phase but had relatively strong ordering at room temperature.

[0121] Furthermore, the XRD results confirmed that P-EPCN5 to P-EPCN9 have similar molecular ordering levels and show similar trends in TC. On the other hand, P-EPCN4, which showed differences in molecular ordering levels in XRD, also showed large differences in TC. These results indicate that the molecular ordering level in the polymer network has a significant impact on the TC value.

[0122] The optimized molecular structures of P-EPCNn model compounds calculated using density functional theory (DFT) at the B3LYP / 6-31G level revealed that the long axis length of the CB molecule of P-EPCNn was approximately 11 Å, corresponding to the peak observed in the 7-8° region, as shown in Figure 13. Furthermore, the same DFT calculation results indicated that the long axis length of the entire side chain was 17 Å for P-EPCN4 and 23 Å for P-EPCN9, confirming the regularity of the pendant groups at around 4°. Because the peaks are not sharp, it is unlikely that P-EPCNn has high crystallinity. However, considering that they are polymeric materials, P-EPCNn possesses a sufficiently high degree of crystalline structure derived from the self-assembly of mesogens.

[0123] Furthermore, the reason for the low TC observed for P-EPCN4, unlike other P-EPCNn, can be confirmed by the correlation between the crystal structure and TC. Unlike other P-EPCNn, P-EPCN4 shows almost no peaks in the low-angle region, indicating insufficient self-assembly of the mesogens, which is the reason for the low TC of P-EPCN4.

[0124] Furthermore, unlike other P-EPCNn molecules with longer spacers, the mesogens of P-EPCN4, which are located four carbon alkyl bonds from the main chain, had difficulty in maintaining sufficient distance for interaction. Furthermore, because of their glassy phase at room temperature, P-EPCNn molecules other than P-EPCN4 can form liquid crystal phases (LC phases) in the rubbery region at room temperature. As a result, the crystallinity and TC of P-EPCN4 were low. Conversely, P-EPCNn molecules exhibited a liquid crystal phase at room temperature, resulting in a high TC.

[0125] Example 3: Synthesis of OMPBn: 4-(oxiran-2-ylmethoxy)phenyl-4-butoxybenzoate Monomer The following reaction scheme 3 shows the synthesis process of OMPBn, an epoxide monomer having phenyl benzoate, a thermotropic liquid crystal structure, in the side chain. Starting from 4-(alkoxy)benzoic acid, HPBn is synthesized by reacting it with hydroquinone, and then OMPBn is obtained by reacting it with epichlorohydrin.

[0126] [ka]

[0127] 1) HPBn: Synthesis of 4-hydroxyphenyl-4-alkoxybenzoate A) n=4 (HPB4) 4-Butoxybenzoic acid (3.00 g, 15.4 mmol), hydroquinone (6.80 g, 61.7 mmol), and BH3O3 (0.0318 g) were placed in a three-neck round-bottom flask and the atmosphere was replaced with argon. Then, 120 ml of toluene and 0.1 ml of sulfuric acid were added and stirred at 130 °C for 12 hours. The resulting solution was concentrated using a rotary evaporator, and the organic matter was extracted with diethyl ether. The organic phase was dried over magnesium sulfate and purified by silica column chromatography using a 7:1 hexane:ethyl acetate solution as a developing solvent. The yield was 24%. 1 H NMR (500MHz, CDCl3): δ=8.13(d,J=9.0Hz,2H),7.06(d,J=9.0Hz,2H),6.97(d,J=8.5Hz,2H),6.85(d,J=9.0H z,2H),4.87(s,1H),4.06(t,J=6.5Hz,2H),1.84-1.78(m,2H),1.54-1.48(m,2H),1.00(t,J=7.5Hz,3H)ppm.

[0128] B) n = 6 (HPB6) This was synthesized in the same manner as A), except that 4-(hexyloxy)benzoic acid was used instead of 4-butoxybenzoic acid. The yield was 58%. 1 H NMR (500MHz, CDCl3): δ=8.13(d,J=9.0Hz,2H),7.07(d,J=9.0Hz,2H),6.97(d,J=9.0Hz,2H),6.86(d,J=9.0Hz,2H),4. 87(s,1H),4.05(t,J=6.5Hz,2H),1.85-1.79(m,2H),1.52-1.45(m,2H),1.37-1.34(m,4H),0.93(t,J=7.0Hz,3H)ppm.

[0129] C) n = 8 (HPB8) This was synthesized in the same manner as A), except that 4-(octyloxy)benzoic acid was used instead of 4-butoxybenzoic acid. The yield was 57%. 1 H NMR (500MHz, CDCl3): δ=8.13(d,J=9.0Hz,2H),7.07(d,J=9.0Hz,2H),6.97(d,J=9.0Hz,2H),6.86(d,J=9.0Hz,2H),4. 88(s,1H),4.05(t,J=6.5Hz,2H),1.86-1.79(m,2H),1.50-1.44(m,2H),1.38-1.29(m,8H),0.91(t,J=7.0Hz,3H)ppm.

[0130] D) n = 10 (HPB10) This was synthesized in the same manner as A), except that 4-(decyloxy)benzoic acid was used instead of 4-butoxybenzoic acid. The yield was 59%. 1 H NMR (500MHz, CDCl3): δ=8.13(d,J=9.0Hz,2H),7.07(d,J=8.5Hz,2H),6.97(d,J=8.5Hz,2H),6.86(d,J=9.0Hz,2H),4. 80(s,1H),4.05(t,J=6.5Hz,2H),1.85-1.79(m,2H),1.51-1.44(m,2H),1.38-1.27(m,10H),0.90(t,J=7.0Hz,3H)ppm.

[0131] 2) OMPBn: Synthesis of 4-(oxiran-2-ylmethoxy)phenyl-4-alkoxybenzoate E)n=4(OMPB4) A three-neck flask was charged with 4-hydroxyphenyl-4-butoxybenzoate (HPB4) (0.50 g, 1.74 mmol), NaOH (0.0701 g, 1.74 mmol), and benzyl trimethyl ammonium bromide (0.401 g, 1.74 mmol). After replacing the atmosphere with argon, 10 ml of epichlorohydrin and 1 ml of water were added and stirred at 70°C for 1 hour. After removing the solvent from the resulting solution, the product was purified by silica column chromatography using a 5:1 hexane:ethyl acetate solution as a developing solvent. The yield was 29%. 1 H NMR (500MHz, CDCl3): δ=8.13(d,J=9.0Hz,2H),7.10(d,J=9.5Hz,2H),6.97(d,J=9. 0Hz,2H),6.95(d,J=9.0Hz,2H),4.22(dd,J=11,3.0Hz,1H),4.05(t,J=6.5Hz,2H),3 .98(dd,J=11,5.5Hz,1H),3.38-3.35(m,1H),2.91(dd,J=5.0,4.5Hz,1H),2.77(dd, J=5.0,2.5Hz,1H),1.84-1.78(m,2H),1.53-1.48(m,2H),0.99(t,J=7.0Hz,3H)ppm. 13 C(125MHz,CDCl3):δ=165.3,163.5,156.1,145.0,132.2,122.6,121.6,115.3,114.3,69.2,68.0,50.1,44.7,31.1,19.2,13.8 ppm.HRMS(+EI):calcd for[C 20 H 22 O5] + :342.1467;found:342.1467 (Figure 14(a) and Figure 15(a)).

[0132] F)n=6(OMPB6) This was synthesized in the same manner as in E) except that HPB6 was used. The yield was 40%. 1H NMR(500MHz,CDCl3):δ=8.11(d,J=9.0Hz,2H),7.10(d,J=9.0Hz,2H),6.97(d,J=9.0Hz, 2H),6.95(d,J=9.0Hz,2H),4.22(dd,J=11,3.0Hz,1H),4.04(t,J=6.5Hz,2H),3.97(dd,J =11,5.5Hz,1H),3.38-3.35(m,1H),2.91(dd,J=5.0,4.5Hz,1H),2.77(dd,J=5.0,2.5Hz, 1H),1.85-1.79(m,2H),1.52-1.45(m,2H),1.37-1.34(m,4H),0.91(t,J=7.0Hz,3H)ppm. 13 C(125MHz,CDCl3):δ=165.3,163.5,156.1,145.0,132.2,122.6,121.6,115.3,1 14.3,69.3,68.3,50.1,44.7,31.6,29.1,25.7,22.6,14.0ppm.HRMS(+EI):calcd for[C 22 H 26 O5] + :370.1780;found:370.1779 (Figure 14(b) and Figure 15(b)).

[0133] G)n=8(OMPB8) This was synthesized in the same manner as in E) except that HPB8 was used. The yield was 35%. 1 H NMR (500MHz, CDCl3): δ=8.11(d,J=9.0Hz,2H),7.10(d,J=9.5Hz,2H),6.97(d,J=9.0Hz, 2H),6.95(d,J=9.0Hz,2H),4.22(dd,J=11,3.0Hz,1H),4.04(t,J=6.5Hz,2H),3.97(dd,J =11,5.5Hz,1H),3.38-3.34(m,1H),2.91(dd,J=5.0,4.5Hz,1H),2.77(dd,J=5.0,2.5Hz, 1H),1.85-1.79(m,2H),1.50-1.44(m,2H),1.38-1.29(m,8H),0.89(t,J=7.0Hz,3H)ppm. 13C(125MHz,CDCl3):δ=165.3,163.5,156.1,145.0,132.2,122.6,121.6,115.3,114.3, 69.3,68.3,50.1,44.7,31.8,29.3,29.2,29.1,26.025.7,14.1ppm.HRMS(+EI):calcd for[C 24 H 30 O5] + :398.2093;found:398.2094 (Figure 14(c) and Figure 15(c)).

[0134] H)n=10(OMPB10) This was synthesized in the same manner as in E) except that HPB10 was used. The yield was 36%. 1 H NMR (500MHz, CDCl3): δ=8.11(d,J=9.0Hz,2H),7.10(d,J=9.0Hz,2H),6.97(d,J=8.5Hz,2 H),6.95(d,J=9.0Hz,2H),4.22(dd,J=11,3.0Hz,1H),4.04(t,J=6.5Hz,2H),3.97(dd,J= 11,5.5Hz,1H),3.39-3.35(m,1H),2.91(dd,J=5.0,4.5Hz,1H),2.77(dd,J=5.0,2.5Hz,1 H),1.85-1.79(m,2H),1.50-1.44(m,2H),1.39-1.28(m,12H),0.88(t,J=7.0Hz,3H)ppm. 13 C(125MHz,CDCl3):δ=165.3,163.5,156.1,145.0,132.2,122.7,121.6,115.4,114.3,69.3, 68.3,50.1,44.7,31.9,29.6,29.6,29.4,29.3,29.1,26.0,25.7,14.1ppm.HRMS(+EI):calcd for[C 26 H 34 O5] + :426.2406;found:426.2409 (Figure 14(d) and Figure 15(d)).

[0135] Example 4: Synthesis of OMPBn polymer (P-OMPBn) The following reaction scheme 4 shows the synthesis process of P-OMPBn, a polyethylene glycol derivative having a liquid crystalline phenylbenzoate side chain. As shown in the following reaction scheme 4, it was synthesized by anionic ring-opening polymerization of the epoxide monomer OMPBn to form the polyethylene glycol backbone.

[0136] [ka]

[0137] A) n = 4 (P-OMPB4) OMPB4 (0.300 g, 0.876 mmol), potassium tert-butoxide (39.0 mg, 327 μmol), and 18-crown-6 (18.0 mg, 65.0 μmol) were placed in a Schlenk tube and purged with argon. 3 mL of toluene was added and the mixture was stirred at room temperature for 3 days to polymerize. The polymerization solution was then precipitated in 50 mL of methanol, and the precipitate was collected. The precipitation process was repeated twice, yielding a brown solid in 81% yield. 1 H NMR(500MHz,CDCl3):δ=8.02-7.96(m,2H),6.91-6.82(m,6H),4.29-4.28(m,2H),4 .08-3.64(m,5H),1.81-1.26(m,4H),1.11(s,9H),0.10-0.81(m,3H)ppm (Figure 16(a)).

[0138] B) n = 6 (P-OMPB6) This was synthesized in the same manner as in A) except that OMPB6 was used. The yield was 82%. 1 H NMR(500MHz,CDCl3):δ=8.02-7.96(m,2H),6.91-6.82(m,6H),4.29-4.28(m,2H),4 .08-3.63(m,5H),1.82-1.26(m,8H),1.11(s,9H),0.10-0.81(m,3H)ppm (Figure 16(b)).

[0139] C) n = 8 (P-OMPB8) This was synthesized in the same manner as in A) except that OMPB8 was used. The yield was 82%. 1 H NMR(500MHz,CDCl3):δ=8.02-7.96(m,2H),6.91-6.82(m,6H),4.29-4.28(m,2H),4 .08-3.63(m,5H),1.82-1.26(m,8H),1.11(s,9H),0.10-0.81(m,3H)ppm (Figure 16(c)).

[0140] D) n = 10 (P-OMPB10) This was synthesized in the same manner as in A) except that OMPB10 was used. The yield was 92%. 1 H NMR(500MHz,CDCl3):δ=8.02-7.94(m,2H),7.12-6.86(m,6H),4.37-4.28(m,2H),4 .05-3.97(m,5H),1.82-1.26(m,16H),1.11(s,9H),0.89-0.87(m,3H)ppm (Figure 16(d)).

[0141] Table 3 below shows the molecular weight of the P-OMPBn obtained above, and Table 4 below shows the physical properties of the P-OMPBn.

[0142] [Table 3]

[0143] [Table 4]

[0144] Although specific aspects of the present invention have been described in detail above, it is clear to those skilled in the art that these specific techniques are merely preferred embodiments and do not limit the scope of the present invention. Therefore, the true scope of the present invention can be said to be defined by the appended claims and their equivalents. The scope of the present invention is defined by the claims below, and all modifications and variations derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.

Claims

1. The following chemical formula (I): 【Chemistry 1】 (In the formula, n is 5, 7, 8, or 9.) Represented by A compound having a thermotropic liquid crystal structure in its side chain.

2. The following chemical formula (II): 【Chemistry 2】 (wherein n is 4, 6, 8, or 10). Represented by A compound having a thermotropic liquid crystal structure in its side chain.

3. A compound obtained by ring-opening polymerization of the compound according to claim 1. A polyethylene glycol polymer comprising:

4. A compound obtained by ring-opening polymerization of the compound according to claim 2. A polyethylene glycol polymer comprising:

5. The following chemical formula (III): 【Chemistry 3】 (In the formula, X1 and X2 may be the same or different and are selected from the monovalent groups of the compounds described in claim 1 or the monovalent groups of the compounds described in claim 2.) It is expressed as When X1 and X2 are the same, the compound is obtained by ring-opening polymerization of the compound according to claim 1 or the compound according to claim 2 corresponding to the X1. When X1 and X2 are different, the compound is obtained by ring-opening polymerization of the compound according to claim 1 or the compound according to claim 2. A polyethylene glycol polymer comprising:

6. The polyethylene glycol polymer is Used in substrates, compounds, adhesives, pads, heat spreads, and heat sinks 5. The polyethylene glycol polymer of claim 3 or 4.

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