Pub Date : 2022-10-02DOI: 10.1080/1358314X.2022.2179827
Takenaka Yoshiko, D. Sato, T. Yamamoto
ABSTRACT Fibre structures of liquid crystals are of particular interest because they are expected to be used in optical fibres, optical devices, and lasers. Micrometre- sized liquid crystal self-assembly demonstrates new optical functions or interfacial interactions which cannot be observed in the bulk. Thermotropic liquid crystals organize fibres by phase transitions or shape changes. The fibrous self- assembly of liquid crystal made by self-organisation was reviewed in the study. We will also introduce the characteristics of these fibres as well as those of lyotropic myelin and lyotropic fibres. Theoretical research on the growth mechanism and physical properties of the fibres has also been summarized.
{"title":"Fibrous self-assembly of liquid crystal made by self-organisation","authors":"Takenaka Yoshiko, D. Sato, T. Yamamoto","doi":"10.1080/1358314X.2022.2179827","DOIUrl":"https://doi.org/10.1080/1358314X.2022.2179827","url":null,"abstract":"ABSTRACT Fibre structures of liquid crystals are of particular interest because they are expected to be used in optical fibres, optical devices, and lasers. Micrometre- sized liquid crystal self-assembly demonstrates new optical functions or interfacial interactions which cannot be observed in the bulk. Thermotropic liquid crystals organize fibres by phase transitions or shape changes. The fibrous self- assembly of liquid crystal made by self-organisation was reviewed in the study. We will also introduce the characteristics of these fibres as well as those of lyotropic myelin and lyotropic fibres. Theoretical research on the growth mechanism and physical properties of the fibres has also been summarized.","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41699978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.1080/1358314X.2022.2168968
M. Ali
ABSTRACT Structure and optical transmission properties of spontaneously formed diffraction gratings by bent-core liquid crystalline materials that exhibit a twist-bend nematic (NTB) phase transition, when confined in thin planar cells are reported. We begin with experimentally measuring the polarisation properties of diffraction peaks up to the second-order and observe a generalised behaviour of polarisation of the first-order peaks. Moreover, we show that the study of the second-order diffraction peaks combined with the proposed preliminary model can be an effective tool to predict the spatial variation of the optic axis. Then, we build a continuum model that describes the formation of gratings as a result of competition between surface conditions and bulk strain due to the shrinking of pseudo-layers and determine the threshold conditions on the onset of a 2D pseudo-layer structure of the NTB phase. We use the beam propagation method and transfer matrix method to calculate the transmissivity of diffracted light by using the spatial variation of the optic axis determined from the modelled structure. It is established that the beam propagation method is superior to the transfer matrix method.
{"title":"Diffraction gratings formed spontaneously by a two-dimensional undulation of the pseudo-layer structure of a twist-bend nematic phase","authors":"M. Ali","doi":"10.1080/1358314X.2022.2168968","DOIUrl":"https://doi.org/10.1080/1358314X.2022.2168968","url":null,"abstract":"ABSTRACT Structure and optical transmission properties of spontaneously formed diffraction gratings by bent-core liquid crystalline materials that exhibit a twist-bend nematic (NTB) phase transition, when confined in thin planar cells are reported. We begin with experimentally measuring the polarisation properties of diffraction peaks up to the second-order and observe a generalised behaviour of polarisation of the first-order peaks. Moreover, we show that the study of the second-order diffraction peaks combined with the proposed preliminary model can be an effective tool to predict the spatial variation of the optic axis. Then, we build a continuum model that describes the formation of gratings as a result of competition between surface conditions and bulk strain due to the shrinking of pseudo-layers and determine the threshold conditions on the onset of a 2D pseudo-layer structure of the NTB phase. We use the beam propagation method and transfer matrix method to calculate the transmissivity of diffracted light by using the spatial variation of the optic axis determined from the modelled structure. It is established that the beam propagation method is superior to the transfer matrix method.","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43379200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.1080/1358314X.2022.2168969
Vidhika Punjani
s were submitted from 43 different countries, which is a significant number. Out of a total of 650 abstracts, 280 abstracts were accepted for oral presentations and 348 abstracts were accepted for poster presentations. Two hundred and eighty abstracts for the oral presentation included 6 tutorials, 5 plenary, 58 invited and 2 public lectures. A group photo of all the on-site participants was also taken on the second last day of the conference (Figure 2). Five scientists were invited to give plenary talks. Prof. Sriram Ramaswamy of the Indian Institute of Science (IISc), Bengaluru, India, opened the technical session with a plenary lecture. He is a powerful orator who discussed the flow, order, defects, fluctuations, and chirality in active LCs (Figure 3, top left). Prof. Maria Blanca Ros of the University of Zaragoza, Spain, delivered the second plenary lecture on strategies for benefiting from the supramolecular interaction of mesogens. The third plenary speaker, Prof. Randall Kamien of the University of Pennsylvania in the United States, discussed the significance of topology in LCs. Prof. Robin Selinger of Kent State University in the United States then discussed morphing liquid crystalline polymers using machine learning. The fifth plenary talk was delivered by Prof. Sung Tae Shin from Korea University, Sejong Campus, Korea, on future video displays. In addition, 28 scientists were invited for keynote lectures. The various topics covered during the keynote lectures included twist-bent nematic mesophases, applications of liquid crystalline elastomers, responsive photonic materials, colloidal LCs, blue phases, topological solitons in frustrated chiral nematics, etc. Keynote speaker, Prof. Nicholas L. Abbott of Cornell University in the United States spoke about the dynamical interaction Figure 1. Left: Padrão dos Descobrimentos (Discoveries Monument), Middle: Belém Tower, Right: Jerónimos Monastery in Lisbon, Portugal (Photos by Vidhika Punjani). Figure 2. Group photo of the on-site participants at the 28 International Liquid Crystal Conference (ILCC 2022) at NOVA University of Lisbon, Portugal (Photo taken by the organizers of ILCC 2022). LIQUID CRYSTALS TODAY 55
{"title":"Report on the 28th International Liquid Crystal Conference 2022 (ILCC 2022)","authors":"Vidhika Punjani","doi":"10.1080/1358314X.2022.2168969","DOIUrl":"https://doi.org/10.1080/1358314X.2022.2168969","url":null,"abstract":"s were submitted from 43 different countries, which is a significant number. Out of a total of 650 abstracts, 280 abstracts were accepted for oral presentations and 348 abstracts were accepted for poster presentations. Two hundred and eighty abstracts for the oral presentation included 6 tutorials, 5 plenary, 58 invited and 2 public lectures. A group photo of all the on-site participants was also taken on the second last day of the conference (Figure 2). Five scientists were invited to give plenary talks. Prof. Sriram Ramaswamy of the Indian Institute of Science (IISc), Bengaluru, India, opened the technical session with a plenary lecture. He is a powerful orator who discussed the flow, order, defects, fluctuations, and chirality in active LCs (Figure 3, top left). Prof. Maria Blanca Ros of the University of Zaragoza, Spain, delivered the second plenary lecture on strategies for benefiting from the supramolecular interaction of mesogens. The third plenary speaker, Prof. Randall Kamien of the University of Pennsylvania in the United States, discussed the significance of topology in LCs. Prof. Robin Selinger of Kent State University in the United States then discussed morphing liquid crystalline polymers using machine learning. The fifth plenary talk was delivered by Prof. Sung Tae Shin from Korea University, Sejong Campus, Korea, on future video displays. In addition, 28 scientists were invited for keynote lectures. The various topics covered during the keynote lectures included twist-bent nematic mesophases, applications of liquid crystalline elastomers, responsive photonic materials, colloidal LCs, blue phases, topological solitons in frustrated chiral nematics, etc. Keynote speaker, Prof. Nicholas L. Abbott of Cornell University in the United States spoke about the dynamical interaction Figure 1. Left: Padrão dos Descobrimentos (Discoveries Monument), Middle: Belém Tower, Right: Jerónimos Monastery in Lisbon, Portugal (Photos by Vidhika Punjani). Figure 2. Group photo of the on-site participants at the 28 International Liquid Crystal Conference (ILCC 2022) at NOVA University of Lisbon, Portugal (Photo taken by the organizers of ILCC 2022). LIQUID CRYSTALS TODAY 55","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44059770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.1080/1358314x.2022.2137993
H. Monobe
The 19th Optics of Liquid Crystals (OLC2021) Satellite Workshop (SWS) 2022 took place in Bankoku Shinryokan, Nago City, Okinawa from 25 until 30 of September 2022. Last year, OLC2021 was affected by the fifth wave of COVID-19 in Japan, and it was not possible to hold a face-to-face meeting with participants on-site. The venue was also the location of the G8 Summit 2000, and it is located on a cape protruding into the sea in central Okinawa. A total of 32 oral invited lectures were given and 27 posters were presented. There were about 60 participants, four scientists came to Japan from overseas to give an invited lecture. All oral lectures were delivered simultaneously live and via Zoom and were made available free of fees to all OLC2021 participants. On Sunday 25th, a public lecture was held as a related event. Ten groups of elementary and junior high school students in Okinawa attended the lecture and listened carefully and with great interest to the research on neutrinos and gravitational waves from two professors at Kyoto University. On Monday, after the opening, Prof. H. Yokoyama of Kent State University, USA, gave a lecture on the podium and Prof. I. Smalyukh of Colorado University were shown on the screen through Zoom. After that, there were two domestic presentations in the morning and two in the afternoon, followed by online presentations from Prof. S. Žumer and Prof. M. Ravik of the University of Ljubljana, Slovenia. All the presentations were followed by lively Q & A from the venue audience. After these talks, there were 14 poster presentations in the area behind the venue, which provided plenty of space for the prevention of the novel corona virus. On Tuesday, after an online lecture by Prof. I-C. Khoo of the Pennsylvania State University, USA, followed by on-site lectures by Prof. M.H. Godinho of the NOVA University Lisbon, Portugal (Figure 1), Prof. G. Chu of Alto University, Finland and Prof. W. Lee of the National Yang Ming Chiao Tung University, Taiwan, two presentations in the afternoon, and an online lecture by Prof. I. Dierking of The University of Manchester, UK, and 13 poster presentations were followed by lively Q & A, as during the previous day (Figure 2). On Wednesday, after four lectures, a group photograph was taken in front of the venue under the clear skies at Okinawa as shown in Figure 3. In the afternoon of Wednesday, a conference excursion to Zakimi Castle Ruin was organised, which took participants to one of the world heritage sites of Japan. The castle was built in the beginning of the 15 century and now lays in ruins except for
{"title":"Report on Optics of Liquid Crystals (OLC) 2021 Satellite Workshop (SWS) 2022, Okinawa","authors":"H. Monobe","doi":"10.1080/1358314x.2022.2137993","DOIUrl":"https://doi.org/10.1080/1358314x.2022.2137993","url":null,"abstract":"The 19th Optics of Liquid Crystals (OLC2021) Satellite Workshop (SWS) 2022 took place in Bankoku Shinryokan, Nago City, Okinawa from 25 until 30 of September 2022. Last year, OLC2021 was affected by the fifth wave of COVID-19 in Japan, and it was not possible to hold a face-to-face meeting with participants on-site. The venue was also the location of the G8 Summit 2000, and it is located on a cape protruding into the sea in central Okinawa. A total of 32 oral invited lectures were given and 27 posters were presented. There were about 60 participants, four scientists came to Japan from overseas to give an invited lecture. All oral lectures were delivered simultaneously live and via Zoom and were made available free of fees to all OLC2021 participants. On Sunday 25th, a public lecture was held as a related event. Ten groups of elementary and junior high school students in Okinawa attended the lecture and listened carefully and with great interest to the research on neutrinos and gravitational waves from two professors at Kyoto University. On Monday, after the opening, Prof. H. Yokoyama of Kent State University, USA, gave a lecture on the podium and Prof. I. Smalyukh of Colorado University were shown on the screen through Zoom. After that, there were two domestic presentations in the morning and two in the afternoon, followed by online presentations from Prof. S. Žumer and Prof. M. Ravik of the University of Ljubljana, Slovenia. All the presentations were followed by lively Q & A from the venue audience. After these talks, there were 14 poster presentations in the area behind the venue, which provided plenty of space for the prevention of the novel corona virus. On Tuesday, after an online lecture by Prof. I-C. Khoo of the Pennsylvania State University, USA, followed by on-site lectures by Prof. M.H. Godinho of the NOVA University Lisbon, Portugal (Figure 1), Prof. G. Chu of Alto University, Finland and Prof. W. Lee of the National Yang Ming Chiao Tung University, Taiwan, two presentations in the afternoon, and an online lecture by Prof. I. Dierking of The University of Manchester, UK, and 13 poster presentations were followed by lively Q & A, as during the previous day (Figure 2). On Wednesday, after four lectures, a group photograph was taken in front of the venue under the clear skies at Okinawa as shown in Figure 3. In the afternoon of Wednesday, a conference excursion to Zakimi Castle Ruin was organised, which took participants to one of the world heritage sites of Japan. The castle was built in the beginning of the 15 century and now lays in ruins except for","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44820805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.1080/1358314X.2022.2137991
M. P. Allen
{"title":"Liquid crystals and their computer simulations","authors":"M. P. Allen","doi":"10.1080/1358314X.2022.2137991","DOIUrl":"https://doi.org/10.1080/1358314X.2022.2137991","url":null,"abstract":"","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45658960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.1080/1358314X.2022.2137989
H. Kitzerow
We mourn the loss of Professor Dr. Gerd Heppke, who passed away on 4 June 2022 at the age of 82. Gerd Heppke was a distinguished researcher and a brilliant teacher, who significantly influenced the progress of liquid crystal research. In this article, some of his achievements are reviewed in recognition of Gerd Heppke’s outstanding merits. Being a physicist by training, Gerd Heppke (Figure 1) received his Ph. D. in 1971 and his habilitation in 1975, became Professor at the Technical University of Berlin (TUB), founded a large research group in the division of physical chemistry, initiated and led an interdisciplinary research programme on liquid crystals at TUB, and established the special research area of ‘Anisotropic Fluids’ in Berlin. Heppke’s ability to guide interdisciplinary work in both physics and chemistry enabled the synthesis and characterisation of many new liquid crystalline compounds, in particular cholesteric liquid crystals and mesogenic chiral additives, ferroelectric smectic liquid crystals, low-molar-mass glass-forming liquid crystals, and bentcore mesogens. Through his extraordinary creativity, his continuous readiness to challenge state-of-the-art mainstream assumptions, his outstanding managing capabilities and hard work, Heppke facilitated the explanation of some surprising experimental observations and the discovery of new effects in the fields of re-entrant smectic phases, helix inversion of cholesteric phases, electric field effects in blue phases, ferroelectricity, antiferroelectricity and ferrielectricity of smectic C-phases, higher ordered smectic phases and phases of bent-core mesogens, optical storage effects, and optical nonlinearities (Table 1) [1–79]. In 1970, when Gerd Heppke started to get interested in liquid crystals [1], standard textbooks of physics and chemistry described the latter as being composed of rod-like molecules, which tend to align parallel to each other in certain temperature ranges, thereby forming mesophases, in particular a nematic (N) phase [in which the locally preferred direction of the molecules is uniform and can be described by the unit vector n, the director], a cholesteric (N*) phase [which appears in the presence of chiral molecules. i. e. molecules without mirror symmetry, and is characterised by a helical director field n(r)], or one of different smectic (Sm) phases [where the molecules form layers in addition to their orientational order]. Television and computer screens were heavy, bulky objects with large power consumption, based on cathode ray tubes (CRT), quite different from the flat liquid crystal displays (LCDs) that are ubiquitous, today. In the early 1970s, first wrist watch Figure 1. Prof. Gerd Heppke 1991 (Foto: Inge Kundel-Saro). LIQUID CRYSTALS TODAY 2022, VOL. 31, NO. 2, 18–27 https://doi.org/10.1080/1358314X.2022.2137989
{"title":"Obituary Prof. Dr. Gerd Heppke","authors":"H. Kitzerow","doi":"10.1080/1358314X.2022.2137989","DOIUrl":"https://doi.org/10.1080/1358314X.2022.2137989","url":null,"abstract":"We mourn the loss of Professor Dr. Gerd Heppke, who passed away on 4 June 2022 at the age of 82. Gerd Heppke was a distinguished researcher and a brilliant teacher, who significantly influenced the progress of liquid crystal research. In this article, some of his achievements are reviewed in recognition of Gerd Heppke’s outstanding merits. Being a physicist by training, Gerd Heppke (Figure 1) received his Ph. D. in 1971 and his habilitation in 1975, became Professor at the Technical University of Berlin (TUB), founded a large research group in the division of physical chemistry, initiated and led an interdisciplinary research programme on liquid crystals at TUB, and established the special research area of ‘Anisotropic Fluids’ in Berlin. Heppke’s ability to guide interdisciplinary work in both physics and chemistry enabled the synthesis and characterisation of many new liquid crystalline compounds, in particular cholesteric liquid crystals and mesogenic chiral additives, ferroelectric smectic liquid crystals, low-molar-mass glass-forming liquid crystals, and bentcore mesogens. Through his extraordinary creativity, his continuous readiness to challenge state-of-the-art mainstream assumptions, his outstanding managing capabilities and hard work, Heppke facilitated the explanation of some surprising experimental observations and the discovery of new effects in the fields of re-entrant smectic phases, helix inversion of cholesteric phases, electric field effects in blue phases, ferroelectricity, antiferroelectricity and ferrielectricity of smectic C-phases, higher ordered smectic phases and phases of bent-core mesogens, optical storage effects, and optical nonlinearities (Table 1) [1–79]. In 1970, when Gerd Heppke started to get interested in liquid crystals [1], standard textbooks of physics and chemistry described the latter as being composed of rod-like molecules, which tend to align parallel to each other in certain temperature ranges, thereby forming mesophases, in particular a nematic (N) phase [in which the locally preferred direction of the molecules is uniform and can be described by the unit vector n, the director], a cholesteric (N*) phase [which appears in the presence of chiral molecules. i. e. molecules without mirror symmetry, and is characterised by a helical director field n(r)], or one of different smectic (Sm) phases [where the molecules form layers in addition to their orientational order]. Television and computer screens were heavy, bulky objects with large power consumption, based on cathode ray tubes (CRT), quite different from the flat liquid crystal displays (LCDs) that are ubiquitous, today. In the early 1970s, first wrist watch Figure 1. Prof. Gerd Heppke 1991 (Foto: Inge Kundel-Saro). LIQUID CRYSTALS TODAY 2022, VOL. 31, NO. 2, 18–27 https://doi.org/10.1080/1358314X.2022.2137989","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45079018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.1080/1358314x.2022.2137992
Ethan I. L. Jull
{"title":"Report of the International Liquid Crystal Conference, NOVA School of Science and Technology, 24th to 29th July 2022","authors":"Ethan I. L. Jull","doi":"10.1080/1358314x.2022.2137992","DOIUrl":"https://doi.org/10.1080/1358314x.2022.2137992","url":null,"abstract":"","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48723243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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