聚合物分散液晶中电场诱导相分离结构的研究
摘要
液晶器件研究已经逐渐进入“液晶后显示时代”，聚合物分散液(PDLC)便是其中一个重要的研究领域。PDLC不需要偏光片和取向层,并且制备工艺简单，应用范围广泛。如电子纸、大尺寸柔性显示、调光玻璃、电子床帘、光栅等。
电子纸技术在进步，液晶应该有进一步作为。本文在聚合物分散液晶(PDLC)的基础上，提出新的聚合物分散向列相液晶双稳模式，以期能够制备出具有双稳性质的，驱动电压低，响应速度快，对比度好的聚合物分散向列相液晶膜，争取能使聚合物分散向列相液晶也能实现双稳态。
为了实现双稳态，本文首先构想获得液晶方微滴结构。当液晶为方微滴时，液晶分子构形就会有一致，沿边，垂边分布，都可能稳定。在实际试验中本文考虑利用施加交流电场方诱导聚合物分散液晶的相分离过程，来验证交流电场对聚合物相分离结构的影响,使聚合物定向生长对液晶分子产生弱锚定。聚合物分散液晶在结晶发生相分离过程的过程中，聚合物会沿电场或垂直于电场方向定向结晶生长。由于聚合物分子长链的锚定作用，相分离完成后，液晶分子会保持沿构形方向一致排列，在显示中易于形成双稳态结构，为双稳态液晶电子书研制提供理论基础和试验检验。
在本文中为了探讨液晶方形微滴的形成，做了大量实验。其中包括正性液晶和负性液晶分别在外加交流电场诱导下定向聚合形成稳态结构。通过实验得到了聚合物分散弱锚定的正性和负性液晶稳态结构。稳态结构的寿命很好，至少可以保持在一个月以上。对实验结果进行理论和对比分析，可以得出结论聚合物分散向列相液晶有双稳态。但是由于时间和精力有限，本文在对两性液晶的配比和实验方面做得研究很少。期待在今后的研究中继续未完成的工作，以使其满足真正实际之要求。
Today, the research of the liquid crystal device has gradually into the“post-era of the LCD”. Polymerdispersed liquid (PDLC) is one important area of the research. The PDLC mode does not need polarizer andalignment layer, but simple process and wide range of applications. It can use to the electronic paper, large sizeflexible, dimming glass, electronic curtain, grating and so on.
The E-paper technology is in progress, the LCD should have a further used. In this paper, based on thePDLC mode, we proposed a new polymer dispersed liquid crystal bistable mode. It will have a bistable nature,low driving voltage, fast response, good contrast.
In order to achieve bistability, we make efforts to obtain the liquid crystal structure of square droplets .When the structure of the liquid crystal droplets are square, the liquid crystal molecules will have the sameconfiguration, along the border, vertical edge distribution, are likely to stabilize. In the actual experiment, weconsider the use of applied AC electric field induced the phase separation of polymer dispersed liquid crystalprocess, to verify the AC electric field on the structure of the polymer phase separation, in order to have thepolymer oriented growth and also have a weak anchor to the liquid crystal. Polymer dispersed liquid crystalphase separation occurs in the crystallization process, the polymer will grow along the direction of electricfield or perpendicular to the electric field oriented. Because of long-chain polymer anchor role, phaseseparation is completed. The liquid crystal molecules will remain in the same direction along the arrayconfiguration, will form the bistable structure and provide a theoretical basis and experimental testing for thedevelopment of E-book.
In order to investigate the formation of the square liquid crystal droplets, we have done a lot ofexperiments, including positive and negative liquid crystal in the applied AC field were directedpolymerization. Through the experiments we have the steady state structure of positive and negative liquidcrystal. The steady-state structure also has a good life, will at least to maintain more than one month. Throughthe theoretical and experimental results of comparative analysis, we can conclude that polymer dispersednematic liquid crystal will have bistable nuture. Because the limited time and energy, we have little researchabout the amphoteric liquid crystal. We are looking forward to do future research to complete the unfinishedwork and make it practical to meet the real requirements.
电子纸技术在进步，液晶应该有进一步作为。本文在聚合物分散液晶(PDLC)的基础上，提出新的聚合物分散向列相液晶双稳模式，以期能够制备出具有双稳性质的，驱动电压低，响应速度快，对比度好的聚合物分散向列相液晶膜，争取能使聚合物分散向列相液晶也能实现双稳态。
为了实现双稳态，本文首先构想获得液晶方微滴结构。当液晶为方微滴时，液晶分子构形就会有一致，沿边，垂边分布，都可能稳定。在实际试验中本文考虑利用施加交流电场方诱导聚合物分散液晶的相分离过程，来验证交流电场对聚合物相分离结构的影响,使聚合物定向生长对液晶分子产生弱锚定。聚合物分散液晶在结晶发生相分离过程的过程中，聚合物会沿电场或垂直于电场方向定向结晶生长。由于聚合物分子长链的锚定作用，相分离完成后，液晶分子会保持沿构形方向一致排列，在显示中易于形成双稳态结构，为双稳态液晶电子书研制提供理论基础和试验检验。
在本文中为了探讨液晶方形微滴的形成，做了大量实验。其中包括正性液晶和负性液晶分别在外加交流电场诱导下定向聚合形成稳态结构。通过实验得到了聚合物分散弱锚定的正性和负性液晶稳态结构。稳态结构的寿命很好，至少可以保持在一个月以上。对实验结果进行理论和对比分析，可以得出结论聚合物分散向列相液晶有双稳态。但是由于时间和精力有限，本文在对两性液晶的配比和实验方面做得研究很少。期待在今后的研究中继续未完成的工作，以使其满足真正实际之要求。
Today, the research of the liquid crystal device has gradually into the“post-era of the LCD”. Polymerdispersed liquid (PDLC) is one important area of the research. The PDLC mode does not need polarizer andalignment layer, but simple process and wide range of applications. It can use to the electronic paper, large sizeflexible, dimming glass, electronic curtain, grating and so on.
The E-paper technology is in progress, the LCD should have a further used. In this paper, based on thePDLC mode, we proposed a new polymer dispersed liquid crystal bistable mode. It will have a bistable nature,low driving voltage, fast response, good contrast.
In order to achieve bistability, we make efforts to obtain the liquid crystal structure of square droplets .When the structure of the liquid crystal droplets are square, the liquid crystal molecules will have the sameconfiguration, along the border, vertical edge distribution, are likely to stabilize. In the actual experiment, weconsider the use of applied AC electric field induced the phase separation of polymer dispersed liquid crystalprocess, to verify the AC electric field on the structure of the polymer phase separation, in order to have thepolymer oriented growth and also have a weak anchor to the liquid crystal. Polymer dispersed liquid crystalphase separation occurs in the crystallization process, the polymer will grow along the direction of electricfield or perpendicular to the electric field oriented. Because of long-chain polymer anchor role, phaseseparation is completed. The liquid crystal molecules will remain in the same direction along the arrayconfiguration, will form the bistable structure and provide a theoretical basis and experimental testing for thedevelopment of E-book.
In order to investigate the formation of the square liquid crystal droplets, we have done a lot ofexperiments, including positive and negative liquid crystal in the applied AC field were directedpolymerization. Through the experiments we have the steady state structure of positive and negative liquidcrystal. The steady-state structure also has a good life, will at least to maintain more than one month. Throughthe theoretical and experimental results of comparative analysis, we can conclude that polymer dispersednematic liquid crystal will have bistable nuture. Because the limited time and energy, we have little researchabout the amphoteric liquid crystal. We are looking forward to do future research to complete the unfinishedwork and make it practical to meet the real requirements.
引文
[1]王新久，液晶光学与液晶显示，北京，科学出版社，2006
[2]赵晓鹏，郭慧林，王建平，北京，化学工业出版社，1998
[3]陈港，王芳，刘晓尧，陈广学，电子纸的研究进展及应用，现代显示，2008年27卷第9期，47-50
[4]闫晓林，朱昌昌，付东，电子纸技术和产业的发展，上海，2010，225-229
[5] Huang X Y, Stefanov M, Yang D K,et al. Cost-Effective，Driving Scheme for Bistable CholestericDisplays [C]，SID 96 Digest, 1996. 359-362.
[6] Ebru A. Büyüktanir, Nadina Gheorghiu, and John L. West，Field-induced polymer wall formation in abistable smectic-A liquid crystal display，APPLIED PHYSICS LETTERS 89, 031101 2006.
[7] Wang Hu, Haiyan Zhao, and Huai Yang，Electrically Controllable Selective Reflection of Chiral NematicLiquid Crystal/Chiral Ionic Liquid Composites，Adv. Mater. 2009, 21, 1–5.
[8]谢毓章，液晶物理学，北京，科学出版社，1998
[9] Bucher, H.K.; Klingbiel, R.T.; VanMeter, J.P. Appl.Phys. Lett. 1974, 25, 186–188.
[10]窦艳丽，聚合物分散液晶膜的制备与研究，博士学位论文，吉林：吉林大学，2007
[11] Park NH,Cho SA,Kim JY, Suh KD. Preparation of polymer dispersed liquid crystal films containing asmall amount of liquid crystalline polymer and their properties, J Appl Polym Sci. 2000；77：3178-88
[12] Ringsdorf H, Schmidt HW, Schneller A. Miscibility studies of polymeric and low molecular weight liquidcrystals and their behavior in an electric field. Makromol Chem Rapid Commun. 1982; 3:745–51
[13] Benthack-Thoms H, Fink elmann H. Phase separation in binary mixtures of nematic liquid crystal sidechain polymers and low-mass nematic liquid crystals. Makromol Chem 1985;186:1895–903
[14] Shimada E, Uchida T. Control of polymer orientation in polymer dispersed liquid crystal(PDLC).J ApplPhys, Part 2 Jpn 1992;31:352–4.
[15] Bhargava R, Wang S Q, Koenig J L.FTIR imaging studies of a new two-step process to produce polymerdispersed liquid crystals. Macromolecules,1999, 32:2748-2760
[16] Hoppe C E, Galante M J, Williams R J J. Polymer-dispersed liquid crystals based on polystyrene andEBBA: analysis of phase diagrams and morphologies generated. Macromol. Chem. Phys., 2003, 204 :928–935
[17] Gogibus N, Maschke U, Benmouna F, et al. Phase diagrams of poly and 5CB blends. J. Polym.Sci.Pol.Phy.,2001,39:581– 588
[18] Shen C, Kyu T. Spinodals in a polymer dispersed liquid crystal. Chem. Phys. , 1995,102(1):556–562
[19] Gogibus N, Maschke U, Benmouna F,et al. Phase diagrams of poly and 5CB blends. J. Polym. Sci. Pol.Phy. , 2001, 39: 581–588
[20] Shen C, Kyu T. Spinodals in a polymer dispersed liquid crystal. Chem. Phys.,1995, 102(1):556–562 [16]H. K. Bucher, R. T. Klingbiel, and J. P. Van Meter,“Frequency addressed liquid crystal field effect,”Appl. Phys. Lett. 25, 1974, 186–188
[21] Kubo S, Gu Z Z,Sato O, et al. Control of the optical properties of liquid crystal-infiltrated inverse opalstructures using photo irradiation and/or an electric field.Chem.Mater.,2005,17:2298-2309
[22] Luther B J, Springer G H, and Higgins D A. Templated droplets and ordered arrays in polymer-dispersedliquid-crystal films.Chem.Mater.,2001,13: 2281–2287
[23] Ikeda T, Tsutsumi O. Optical switching and image storage by means of azo benzene liquid crystal film.Science 1995; 268: 1873–5.
[24]何曼君，张红东，陈维孝，高分子物理学，上海，复旦大学出版社，2008
[25]毛益民,杨其,李光宪,黄亚江，剪切场下聚合物结晶形态学研究进展，高分子材料科学与工程，2004年第20卷第1期，36-39
[26]刘强,崔建忠,刘晓涛,许光明，静电场对熔融结晶聚丙烯薄膜显微形态的影响，高分子材料科学与工程，2005年第21卷第5期，174-176
[27]刘强,葛研,郭树国,郭北涛,宗琳，磁场诱导下的等规聚丙烯薄膜显微结构分析，沈阳化工学院学报，2005年第19卷第1期，28-31
[28] Giguere R J , Bray T L ,Duncan S M, et al. Application of Commercial Microwave Ovens to OrganicSynthesis [ J ] . Tetrahedron Letterpress, 1986 , 27 (41) : 4945 - 4948
[29] Jong-Hyun Kim, Makoto Yoneya, Hiroshi Yokoyama, Tristable nematic liquid-crystal device usingmicropatterned surface alignment, NATURE ,VOL 420, 14 ,2002.
[30]范志新，液晶器件工艺基础，北京，北京邮电大学出版社，2000
[2]赵晓鹏，郭慧林，王建平，北京，化学工业出版社，1998
[3]陈港，王芳，刘晓尧，陈广学，电子纸的研究进展及应用，现代显示，2008年27卷第9期，47-50
[4]闫晓林，朱昌昌，付东，电子纸技术和产业的发展，上海，2010，225-229
[5] Huang X Y, Stefanov M, Yang D K,et al. Cost-Effective，Driving Scheme for Bistable CholestericDisplays [C]，SID 96 Digest, 1996. 359-362.
[6] Ebru A. Büyüktanir, Nadina Gheorghiu, and John L. West，Field-induced polymer wall formation in abistable smectic-A liquid crystal display，APPLIED PHYSICS LETTERS 89, 031101 2006.
[7] Wang Hu, Haiyan Zhao, and Huai Yang，Electrically Controllable Selective Reflection of Chiral NematicLiquid Crystal/Chiral Ionic Liquid Composites，Adv. Mater. 2009, 21, 1–5.
[8]谢毓章，液晶物理学，北京，科学出版社，1998
[9] Bucher, H.K.; Klingbiel, R.T.; VanMeter, J.P. Appl.Phys. Lett. 1974, 25, 186–188.
[10]窦艳丽，聚合物分散液晶膜的制备与研究，博士学位论文，吉林：吉林大学，2007
[11] Park NH,Cho SA,Kim JY, Suh KD. Preparation of polymer dispersed liquid crystal films containing asmall amount of liquid crystalline polymer and their properties, J Appl Polym Sci. 2000；77：3178-88
[12] Ringsdorf H, Schmidt HW, Schneller A. Miscibility studies of polymeric and low molecular weight liquidcrystals and their behavior in an electric field. Makromol Chem Rapid Commun. 1982; 3:745–51
[13] Benthack-Thoms H, Fink elmann H. Phase separation in binary mixtures of nematic liquid crystal sidechain polymers and low-mass nematic liquid crystals. Makromol Chem 1985;186:1895–903
[14] Shimada E, Uchida T. Control of polymer orientation in polymer dispersed liquid crystal(PDLC).J ApplPhys, Part 2 Jpn 1992;31:352–4.
[15] Bhargava R, Wang S Q, Koenig J L.FTIR imaging studies of a new two-step process to produce polymerdispersed liquid crystals. Macromolecules,1999, 32:2748-2760
[16] Hoppe C E, Galante M J, Williams R J J. Polymer-dispersed liquid crystals based on polystyrene andEBBA: analysis of phase diagrams and morphologies generated. Macromol. Chem. Phys., 2003, 204 :928–935
[17] Gogibus N, Maschke U, Benmouna F, et al. Phase diagrams of poly and 5CB blends. J. Polym.Sci.Pol.Phy.,2001,39:581– 588
[18] Shen C, Kyu T. Spinodals in a polymer dispersed liquid crystal. Chem. Phys. , 1995,102(1):556–562
[19] Gogibus N, Maschke U, Benmouna F,et al. Phase diagrams of poly and 5CB blends. J. Polym. Sci. Pol.Phy. , 2001, 39: 581–588
[20] Shen C, Kyu T. Spinodals in a polymer dispersed liquid crystal. Chem. Phys.,1995, 102(1):556–562 [16]H. K. Bucher, R. T. Klingbiel, and J. P. Van Meter,“Frequency addressed liquid crystal field effect,”Appl. Phys. Lett. 25, 1974, 186–188
[21] Kubo S, Gu Z Z,Sato O, et al. Control of the optical properties of liquid crystal-infiltrated inverse opalstructures using photo irradiation and/or an electric field.Chem.Mater.,2005,17:2298-2309
[22] Luther B J, Springer G H, and Higgins D A. Templated droplets and ordered arrays in polymer-dispersedliquid-crystal films.Chem.Mater.,2001,13: 2281–2287
[23] Ikeda T, Tsutsumi O. Optical switching and image storage by means of azo benzene liquid crystal film.Science 1995; 268: 1873–5.
[24]何曼君，张红东，陈维孝，高分子物理学，上海，复旦大学出版社，2008
[25]毛益民,杨其,李光宪,黄亚江，剪切场下聚合物结晶形态学研究进展，高分子材料科学与工程，2004年第20卷第1期，36-39
[26]刘强,崔建忠,刘晓涛,许光明，静电场对熔融结晶聚丙烯薄膜显微形态的影响，高分子材料科学与工程，2005年第21卷第5期，174-176
[27]刘强,葛研,郭树国,郭北涛,宗琳，磁场诱导下的等规聚丙烯薄膜显微结构分析，沈阳化工学院学报，2005年第19卷第1期，28-31
[28] Giguere R J , Bray T L ,Duncan S M, et al. Application of Commercial Microwave Ovens to OrganicSynthesis [ J ] . Tetrahedron Letterpress, 1986 , 27 (41) : 4945 - 4948
[29] Jong-Hyun Kim, Makoto Yoneya, Hiroshi Yokoyama, Tristable nematic liquid-crystal device usingmicropatterned surface alignment, NATURE ,VOL 420, 14 ,2002.
[30]范志新，液晶器件工艺基础，北京，北京邮电大学出版社，2000