李敏
液晶超分子、光电功能分子合成与性质研究
个性化签名
- 姓名:李敏
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学术头衔:
博士生导师
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学科领域:
高分子化学
- 研究兴趣:液晶超分子、光电功能分子合成与性质研究
李敏,女,1965年12月生,1988年获吉林大学化学系高分子材料理学学士学位,1993年获中国科学院长春应用化学研究所高分子物理专业博士学位,1994年吉林大学博士后,1996年起在吉林大学任教,由于教学和科研业绩突出,2000年被破格提升为教授,2001年遴选为博士生导师。1999年获国家留学基金委员会的经费支持在英国的SOUTHAMPTON 大学化学系作高级访问学者。 主要研究方向为液晶超分子、光电功能分子合成与性质研究,研究结果在Tetrahedron,Macromolecular Rapid Communication, Polymer, Liquid Crystals等国内外有影响的学术期刊上发表学术论文近50篇,其中SCI论文35篇,研究论文在“吉林省第五届自然科学优秀学术论文、科技建议奖”评选中获学术论文二等奖(1篇)和三等奖(2篇)。先后主持国家自然科学基金3项,教育部“新世纪优秀人才支持计划”项目、教育部“优秀青年教师资助计划”项目和吉林省科技厅基础研究项目的研究工作。2004年入选教育部新世纪优秀人才支持计划。是Polymer, J.Org.Chem,高等学校化学学报、应用化学等学术期刊的通信评审人。
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成果阅读
672
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成果数
10
李敏, HONGJIN QIU, MIN LI*, XINFANG CHEN, FENGYING JING, and ENLE ZHOU
Liquid Crystals, 1998, Vol. 25, No.3, 419-425,-0001,():
-1年11月30日
Two series of monomers, namely n-1-bromo-[ 4-(4-nitrophenylazo)phenyloxy]alkanes (Bn, n=2, 3, 4, 5, 6, 8, 10) and N-n-[4-(4-nitrophenylazo)phenyloxy]alkyl diethanolamines (Cn, n=3, 5, 6, 10), were synthesized and characterized. Their thermal behaviour was studied by di€ erential scanning calorimetry (DSC), wide angle X-ray di€ ractometry (WAXD) and polarizing optical microscopy (POM) equipped with a hot stage. The results showed that the Bns (n> 6) exhibit monotropic nematic liquid crystalline behaviour; no liquid crystalline phase was found for the Bns (n<6), while for the Cns, enantiotropic smectic liquid crystallinity for n=5, 6, 10 was seen, and for n=3 monotropic smectic phases were found. This di€ erent phase behaviour between Bn and Cn compounds is attributed to their di€ erent end groups. The FTIR analysis of Cn indicated that there exists an intermolecular hydrogen bond between hydroxy groups, so that more stable liquid crystalline phase are formed. The effect of the length of the flexible chain on the thermal behaviour is also discussed.
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李敏, BINGLIAN BAI†, MIN LI*†, DONGMEI PANG†, YUQING WU‡, and HAIHAO ZHANG‡
Liquid Crystals, Vol. 32, No.6, June 2005, 755-761,-0001,():
-1年11月30日
Novel hydrazide-modified 4-methoxyazobenzene derivatives, namely 4-{n-[4-(4-methoxyphenylazo) phenoxy] alkoxy} benzoic acid hydrazide (Dn, n=3,6,10), were synthesized and characterized. The FTIR spectra of the Dn compounds were examined in the range 3500-1000cm-1 at different temperatures, and two different kinds of ydrogen-bonded supramolecular structure are proposed. The length as well as the parity of the alkyl spacer in Dn play key roles in determining both the supramolecular structure and the liquid crystalline properties. D6 and D10 are monotropic nematic liquid crystals, while D3, is a nonmesomorphic material. The melting temperatures of Dn are higher than those of the 4-{n-[4-(4-methoxyphenylazo)phenoxy] alkoxy}benzoic ethyl esters (Cn, n=3,6,10) due to the formation of hydrogen bonds.
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李敏, Min Li, Zhijun Hu, Gang Chen, Xinfang Chen
Journal of Applied Polymer Science, Vol. 88, 2275-2279 (2003),-0001,():
-1年11月30日
Side-chain liquid-crystalline copolymethacrylates (PMm's), containing para-nitro azobenzene as the mesogenic group and 2-hydroxylethyl methacrylate (HEMA) as a comonomer, were synthesized by radical polymerization, and their corresponding liquid-crystalline elastomers (LCEm's) were prepared through chemical crosslinking. All of the polymers (PMm's) and the elastomers studied showed enantiotropic smectic A phases; the clearing temperature (Ti) of the PMm polymers decreased with increasing amount of HEMA, and the Ti of the corresponding LCEm's decreased compared to that of their precursors. Small-angle X-ray scattering studies on the copolymers quenched from their liquid-crystalline phases indicated that the characteristic distance increased with increasing amorphous component content and thus, the amorphous components were in between the smectic layers.
liquid-crystalline polymer, phase behavior
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李敏, Guojie Wang, Min Li*, Xinfang Chen, Fang Wu, Wenjing Tian, Jiacong Shen
Macromol. Rapid Commun. 20, 591-594 (1999),-0001,():
-1年11月30日
A novel poly (1,4-phenylenevinylene) (PPV) derivative containing an azobenzene side chain was prepared via a dehydrochlorination route. Poly{2-methoxy-5-[(4-(4-methoxyphenylazo)phenyloxy)- hexyloxy]-1,4-phenylenevinylene}, which is soluble in ordinary solvents such as chloroform, tetrahydrofuran (THF), acetone, xylene, etc., was characterized by FTIR, 1H NMR, GPC, and UV-visible spectroscopies, thermogravimetric analysis (TGA), and cyclic voltammetry. The photoluminescence spectrum of the polymer showed an emission maximum at λ=550nm.
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【期刊论文】Inverse Suspension Polymerization of Sodium Acrylate
李敏, GUOJIE WANG, MIN LI, XINFANG CHEN
J Appl Polym Sci 65: 789-794, 1997,-0001,():
-1年11月30日
A superwater-absorbent sodium polyacrylate was synthesized by inverse suspension polymerization, using Span60 as the dispersant, cyclohexane as the organic phase, N, N*-methylene bisacrylamide as the crosslinking agent, and potassium persulfate as the initiator. The effect of reaction conditions such as reaction time, crosslinking agent, and dispersant on deionized-water and saline solution absorbability, average particle size, and distribution of the sol-gel of the resin is discussed. The deionizedwater and saline solution absorbabilities of sodium polyacrylate prepared at proper conditions were 300-1200 and 50-120, respectively; the number-average particle size was 10-50mm and the gel portion was 20-85% by weight.
superwater-absorbent resin, sodium acrylate, inverse suspension polymerization, degree of bsorption, gel
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李敏, Dongmei Pang, Haitao Wang, and Min Li*
Tetrahedron 61 (2005) 6108-6114,-0001,():
-1年11月30日
Six dissymmetrical dihydrazide derivatives, N-(4-alkoxybenzoyl)-N0-(40-nitrobenzoyl) hydrazine (Cn-NO2) and N-(4-alkoxybenzoyl)-N0-(40-biphenyl carbonyl) hydrazine (Cn-Ph), were synthesized and investigated by means of ifferential scanning calorimetry, polarized optical microscopy and wide angle X-ray diffraction. The compounds exhibit smectic A1 phase. Based on the results of 1H NMR and variable temperature FT-IR spectroscopy, lateral intermolecular hydrogen bonding between-C=O and-N-H groups was proposed and the effect of hydrogen bonding on the phase transitions was discussed. It was concluded that the combination of lateral intermolecular hydrogen bonding and microphase segregation stabilized the smectic A phase.
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【期刊论文】Soluble conjugated copolymers based on poly (1,4-phenylenevinylene)
李敏, Guojie Wanga, *, Min Lia, Chaowei Guoa, Fang Wub, Wenjing Tianb, Xinfang Chena, Jiacong Shenb
Polymer 41 (2000) 2309-2312,-0001,():
-1年11月30日
Soluble conjugated copolymers containing 2-methoxy-5 ((4-(4-methoxyphenylazo) phenyloxy) hexyloxy)-1,4-phenylenevinylene (MHPV) and 2-methoxy-5-n-butoxy-1,4-phenylenevinylene (MBPV) units were prepared via a dehydrochlorination route. The copolymers were characterized by FTIR, 1H NMR, GPC cyclic voltammetry, UV-Visible and photoluminescence spectroscopies. q1999 Elsevier Science Ltd. All rights reserved.
Phenylenevinylene copolymers, Azobenzene, Photoluminescence
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李敏, Xiaobo Sun, , Min Li, Dong Liu, Peng Zhang, Wenjing Tian
Journal of Applied Polymer Science, Vol. 91, 396-403 (2004),-0001,():
-1年11月30日
Two novel poly (1,4-phenylenevinylene)(PPV) derivatives containing liquid crystalline oxadiazole side chains were prepared by a dehydrochlorination process. The homopolymer poly (2-methoxy-5-((2-methoxy-phenyl)-5-hexyloxy-phenyloxy-1,3,4-oxadiazole)-1,4-phenylenevinylene)(HO-PE6) is insoluble in common solvents, whereas the copolymer poly(2-methoxy-5-((2-methoxy-phenyl)-5-hexyloxyphenyloxy-1,3,4-oxadiazole))-(2-methoxy-5-(2-methylhexyloxy))-1,4-phenylenevinylene)(CO-PE6) is soluble in common solvents such as chloroform, THF, and p-xylene. The molecular structure of CO-PE6 was con.rmed by FTIR, 1H-NMR, UV-vis spectroscopy, and polarized light microscopy. CO-PE6 showed a maximum emission at 556 nm in chloroform and at 564nm in 20074013. solid. lm, when excited at 450nm. The maximum electroluminescence emission of the device indium-tin oxide (ITO)CO-PE6/Al is at 555nm. The turn-on voltage of LEDs based on CO-PE6 and MEH-PPV is 6.5 and 8.5V, respectively. The electron mobility of CO-PE6 is higher than that of MEH-PPV based on the results of current-voltage and lectrochemical behavior of both MEH–PPV and CO-PE6.
light-emitting polymers, poly (, p-phenylenevinylene), derivatives, electron transport, 1,, 3,, 4-oxadiazole group, electrochemistry
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【期刊论文】Synthesis and characterization of novel crosslinkable side-chain liquid crystalline polyesters
李敏, Min Li*, Hongjin Qiu, Xinfang Chen, Enle Zhou, Fengying Jing
Macromol. Chem. Phys. 200, 834-839 (1999),-0001,():
-1年11月30日
Crosslinkable side-chain liquid crystalline polyesters PCn from N-[n-(4-(4-nitrophenylazo) phenyloxy) alkyl] diethanolamine (Cn, n=3, 5, 6, 10) as mesogenic monomers and maleic anhydride were ynthesized and characterized. The thermal properties of PCn's were studied by means of DSC, polarized optical microscopy (POM) and wide angle X-ray diffraction (WAXD), and the results showed that all the olymers studied exhibit enantiotropic liquid crystallinity. In the molar mass independent region, the relatively high content of cis-CH=CH-groups in the polymer backbone of PC3 causes an increase of the melting temperature (Tm) and a decrease of Tg and isotropisation temperature (Ti). The crosslinking of PCn in the radical polymerization with styrene was confirmed by FTIR spectroscopy. The absorption band at 1300cm-1 attributed to the in-plane C1H-bending vibration of trans 1CH2CH1 in the polymer backbone disappeared after crosslinking, indicating that the trans 1CH2CH1 functions are consumed in the crosslinking polymerization of styrene.
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李敏, GUOJIE WANG, , FANG WU, MIN LI, WENJING TIAN, XINFANG CHEN, JIACONG SHEN
Journal of Applied Polymer Science, Vol. 78, 2180-2185 (2000),-0001,():
-1年11月30日
The synthesis of poly (2-methoxy-5-n-butoxy-p-phenylene vinylene)(MBPPV) via a dehydrochlorination of 2-methoxy-5-n-butoxy-a, a 9-dichloro-p-xylene is described. The soluble polymer was characterized by elemental analysis, Fourier transforminfrared (FTIR), 1H nuclear magnetic resonance (NMR), and UV-visible spectroscopy. The energy gap (Eg) of the polymer was 2.53eV determined by cyclic voltammogram. Light-emitting diode (LED) and light-emitting electrochemical cell (LEC) with the polymer were fabricated. The LED displayed unipolar I-V dependence with the turn-on voltage at 4.2V. I-V curve of the LEC with poly(ethylene oxide) (PEO, Mw 2×10×4) displayed mirror symmetry with the turn-on voltage at 2.7V, but to the device with PEO (Mw 5×10×6) no mirror symmetry was observed, the turn-on voltages at 12.7V, 211.5V. The emission maximum of the polymer in chloroform was at λ=550nm, whereas the emission maxima of the LEDat 5.2V and the LECat 4.8V were at λ=566, 569nm, respectively.
conjugated polymer, photoluminescence, electroluminescence, light emitting diodes, light emitting cells
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