پیوندهای مفید
اخبار و اعلانات
آمار
| تعداد نشریات | 25 |
| تعداد شماره‌ها | 932 |
| تعداد مقالات | 7,652 |
| تعداد مشاهده مقاله | 12,494,635 |
| تعداد دریافت فایل اصل مقاله | 8,886,238 |
Influence of surface alignment on the orientation behavior of a liquid crystal cell near nanoscale grooved surfaces | ||
| Journal of Interfaces, Thin Films, and Low dimensional systems | ||
| دوره 6، شماره 2، فروردین 2023، صفحه 657-668 اصل مقاله (1.53 M) | ||
| نوع مقاله: Original Article | ||
| شناسه دیجیتال (DOI): 10.22051/jitl.2023.43616.1085 | ||
| نویسندگان | ||
| Saeedeh Shoarinejad* 1؛ Zahra Keikavousi1؛ Mohammad Reza Mozaffari2 | ||
| 1Department of Theoretical and Nanophysics, Faculty of Physics, Alzahra University, Tehran, Iran. | ||
| 2Department of Physics, University of Qom, Qom, Iran. | ||
| چکیده | ||
| In this work, we investigate the anchoring energy of a nematic liquid crystal cell with one patterned and one unpatterned surface. Surface reorientation effects are studied both in the absence of an external electric field and under the action of an external field. We consider the contribution of the saddle-splay surface energy and obtain the anchoring energies of the system. Director profiles are determined and the influence of the geometry, as well as the pitch values of the sinusoidal surface, are discussed. The reorientation of liquid crystal molecules in the vicinity of a nano-size grooved surface and the effect of different surface energy terms on the orientational behavior of a liquid crystal near the surfaces are investigated. Our calculations were performed using the Oseen-Frank theory based on nano-scale groove models. Our results reveal the crucial effects of surface and external fields on nematic reorientational behavior near a patterned surface. Also, our findings highlight the importance of the saddle-splay surface energy when comparing the Fukuda and Berreman models. Besides, it turns out that the presence of an external electric field significantly affects the results reported by these models. | ||
| کلیدواژه‌ها | ||
| Nematic Liquid Crystals؛ Surface grooves؛ Anchoring energy؛ Director profile؛ groove pitches | ||
| عنوان مقاله [English] | ||
| تاثیر تنظیم سطحی بر رفتار سمتگیری یک بلور مایع در نزدیکی سطوح شیاردار نانومقیاس | ||
| نویسندگان [English] | ||
| سعیده شعاری نژاد1؛ زهرا کیکاووسی1؛ محمد رضا مظفری2 | ||
| 1دانشکده فیزیک، دانشگاه الزهرا، تهران، ایران. | ||
| 2گروه فیزیک، دانشگاه قم، قم، ایران. | ||
| چکیده [English] | ||
| در این کار، انرژی چنگ زدگی یک سلول بلور مایع نماتیک با یک سطح طرح دار و یک سطح بدون الگو را بررسی می کنیم. اثرات سمت گیری مجدد سطح، هم در غیاب میدان الکتریکی خارجی و هم تحت عمل یک میدان خارجی، مورد مطالعه قرار می گیرد. ما سهم انرژی سطحی زینی را در نظر می گیریم و انرژی های چنگ زدگی سیستم را بدست می آوریم. پروفایل های جهت نما تعیین می شوند و تأثیر هندسه سیستم ، همچنین اثر اندازه گام سطح سینوسی، مورد بحث قرار می گیرند. سمتگیری مجدد مولکول‌های بلورمایع در مجاورت یک سطح شیاردار نانومقیاس و تأثیر جملات مختلف انرژی سطحی بر رفتار سمتگیری بلور مایع در نزدیکی سطوح مورد بررسی قرار می‌گیرد. محاسبات ما با استفاده از نظریه اوسین-فرانک بر اساس مدل‌های شیارهای نانومقیاس انجام شده است. نتایج ما اثرات حیاتی میدان‌های سطحی و خارجی را بر رفتار سمتگیری مجدد نماتیک در نزدیکی یک سطح الگودارنانومقیاس نشان می‌دهد. همچنین، یافته‌های ما اهمیت انرژی سطحی زینی را هنگام مقایسه مدل‌های فوکودا و برمن، نشان می‌دهد. علاوه بر این، به نظر می رسد که وجود یک میدان الکتریکی خارجی به طور قابل توجهی بر نتایج گزارش شده توسط این مدل ها تأثیر می گذارد. | ||
| کلیدواژه‌ها [English] | ||
| بلور مایع نماتیک, شیارهای سطحی, انرژی چنگ زدگی, پروفایل جهت نما, گام های شیار | ||
| مراجع | ||
|
[1] Y. Choi, H. Yokoyama and J. Seog Gwag, "Determination of surface nematic liquid crystal anchoring strength using nano-scale surface grooves", Optics Express, 21 (2013) 12135.
[2] K. Haruna and H. Okada, "Alignment of liquid crystals with 200 nm-sized V-shaped groove structure fabricated by nano-imprint lithography", Journal of Molecular Liquids, 286 (2019) 110830.
[3] P. J. Collings and J. S. Patel, Handbook of Liquid Crystal Research, Oxford University Press, Oxford, 1997, Chap. 6.
[4] Y. Shang, J. Wang, T. Ikeda and L. Jiang, "Bio-inspired Liquid crystal Actuator materials", Journal of Materials chemistry C, 7 (2019) 3413.
[5] C. Gear, K. Diest, V. Liberman and M. Rothschild, "Engineered liquid crystal anchoring energies with nanopatterned surfaces", Optics Express, 23 (2015) 807.
[6] J. S. Gwag, J. Hyuk Kwon, M. Oh-e, J.-i. Niitsuma, M. Yoneya and H. Yokoyama, "Higher-order surface free energy in azimuthal nematic anchoring on nanopatterned grooves", Applied Physics Letters, 95 (2009) 103101.
[7] J. i. Fukuda, Yoneya Makoto and H. Yokoyama, "Anchoring of a nematic liquid crystal induced by surface grooves: A numerical study", Physical Review E, 77 (2008) 030701.
[8] Y. T. Kim, S. Hwang, J.-H. Hong and S.-D. Lee, "Alignment layerless flexible liquid crystal display fabricated by an imprinting technique at ambient temperature", Applied Physics Letters, 89 (2006) 173506.
[9] D. C. Flanders, D. C. Shaver and H. I. Smith, "Alignment of liquid crystals using submicrometer periodicity gratings", Applied Physics Letters, 32 (1978) 597.
[10] D. H. Kim, D. Wook Lee, J. Young Oh, J. Won and D.-S. Seo, "Nanopatterning of polymer/Gallium Oxide thin films by UV-Curing Nanoimprint Lithography for Liquid Crystal Alignment", ACS Applied Nano Materials, 5 (2022) 1435.
[11] P. Kumar, C. Jaggi, V. Sharma and K. Kumar Raina, "Advancements of vertically aligned liquid crystal displays", Micron, 81 (2016) 34.
[12] D. H. Kim, J. Hwan Lee, D. Wook Lee, J. Young Oh, J. Won, Y. Liu and D.-S. Seo, "Controlled nano structures on solution-processed inorganic/organic film for liquid crystal application", Journal of Sol-Gel Science and Technology, 104 (2022) 412.
[13] B. Zhang, F. K. Lee, O. K. C. Tsui and P. Sheng, "Liquid Crystal orientation transition on microtextured substrates", Physical Review Letters, 91 (2003) 215501.
[14] H. Chen, C. Xu, G. Xiao, Z. Chen, M. Yi and J. Zhang, "Surface anchoring behavior of 5CB liquid crystal confined between iron surfaces: A molecular dynamic study", Applied Surface Science, 508 (2020) 145284.
[15] H. Chen, Q. sun, G. Xiao, Z. Chen, M. Yi, J. Zhang and C. Xu, "Molecular Dynamic simulations on the flow behavior of 5CB liquid crystal sandwiched between iron walls", Advanced Theory and Simulation, 5 (2022) 2200346.
[16] J. Yang, Y. Yuan, K. Li, T. Amann, C. Wang, C. Yuan and A. Neville, "Ultralow friction of 5CB liquid crystal on steel surfaces using a 1,3-diketone additive", Wear, 480-481 (2021) 203934.
[17] J. Prakash, A. Kumar and S. Chauhan, "Aligning Liquid Crystal Materials through Nanoparticles: A review of recent progress", Liquids, 2 (2022) 50.
[18] B. Jerome, "Surface effects and anchoring in liquid crystals", Reports on progress in physics, 54, (1991) 391.
[19] A. Rapini and M. Papoular, "Distorsion d'une lamelle ne'matique sous champ magne'tique conditions d'ancrage aux parois", Le Journal de Physique Colloques, 30 (1969) C4-54.
[20] Y. Guo-chen, Z. Shu-jing, h. Li-jun and G. Rong-Hua, "the formula of anchoring energy for a nematic liquid crystal", Liq. Cryst., 31 (2004) 1093.
[21] G. Babakhanova and O. D.Laverntovich, "The Techniques of Surface Alignment of Liquid Crystals", Modern Problems of the Physics of Liquid Systems, Selected Reviews from the 8th International Conference "Physics of Liquid Matter: Modern Problems", Kyiv, Ukraine, May 18-22, 2018, Springer International Publishing, 2019.
[22] D. W.Berreman, "Alignment of liquid crystals by grooved surfaces", Molecular Crystals and Liquid Crystals, 23 (1973) 215.
[23] D. W.Berreman, "Solid surface shape and the alignment of an adjacent nematic liquid crystal", Physical Review Letters, 28 (1972) 1683.
[24] J. i. Fukuda, M. Yoneya and H. Yokoyama, "Surface-groove induced azimuthal anchoring of a nematic liquid crystal: Berreman's model reexamined", Physical Review Letters, 98 (2007) 187803.
[25] J. i. Fukuda, M. Yoneya and H. Yokoyama, "Erratum: Surface-groove-induced azimuthal anchoring of a nematic liquid crystal: Berreman's Model Reexamined [Phys.Rev.Lett.98,187803 (2007)]", Physical Review Letters, 99 (2007) 139902.
[26] O. A.Rojas-Gomez, M. M. Telo da Gama and J. M. Romero-Enrique, "Wetting of Nematic Liquid crystals on crenellated substrates: A Frank-Oseen Approach", Cryatals, 9 (2019) 430.
[27] D.Demus, J. Goodby, G. Gray, H. Spiess and V. Vill, Handbook of liquid crystals, vol. 2 A: Low molecular weight liquid crystals I, Wiley-VCH, 1998.
[28] S. Kralj, S. Zumer and D. Allender, "Nematic-isotropic phase transition in a liquid-crystal droplet", Physical Review A, 43 (1991) 2943.
[29] J. Nehring and A. Saupe, "On the elastic theory of uniaxial liquid crystals", Journal of Chemical Physics, 54 (1971) 337.
[30] J. i. Fukuda, M. Yoneya and H. Yokoyama, "Consistent numerical evaluation of the anchoring energy of a grooved surface", Physical Review E, 79 (2009) 011705.
[31] D. G. Ryu, G. J. Choi, R. Kumar Mishra and J. Seog Gwag, "Anchoring energy of nematic liquid crystals on zinc oxide film", Journal of the Korean Physival Society, 78 (2021) 307.
[32] M.Emdadi, J. Poursamad, M. Sahrai and F. Moghaddas, "Behaviour of nematic liquid crystals doped with ferroelectric nanoparticles in the presence of an electric field", Molecular Physics, 116, (2018) 1650.
[33] Z. Keikavousi, S. Shoarinejad و M. R. Mozaffari, "Adjusted Structures in Nematic Liquid Crystals", Iranian Journal of Applied Physics, 10 (2020) 29.
[34] S. Shoarinejad and M. Shahzamanian, "On the numerical study of Frederick transition in nematic liquid crystals", Journal of Molecular Liquids, 138 (2008) 14.
[35] S. Khosla, S. Lal and A. Devi, "Review of Blue phase liquid crystal devices", AIP Conference Proceedings, 2352 (2021) 020037.
[36] R.H.Self, C. Please and T. Sluckin, "Deformation of nematic liquid crystals in an electric field", European Journal of Applied Mathematics, 13, (2002) 1.
[37] D. K. Yang and S.-T. Wu, Fundamentals of liquid crystal devices, second ed., Willey, England, 2014.
[38] M. Ravnik, "Colloidal structures confined to thin nematic layers: doctoral thesis, M. Ravnik, 2009.
[39] J. i. Fukuda and S. Zumer, "Field-induced dynamics and structures in a cholesteric-blue-phase cell", Physical Review E, 87 (2013) 042506.
[40] M. Kleman and O. D.Lavrentovich, Soft matter physics: an introduction, NY: Springer New York, 2003.
[41] U.Wolff, W. Greubel and H. Kruger, "The homogeneous alignment of liquid crystal layers", Molecular Crystals and Liquid Crystals, 23 (1973) 187. | ||
|
آمار تعداد مشاهده مقاله: 166 تعداد دریافت فایل اصل مقاله: 173 |
||