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Markelov DA, Matveev VV, Ingman P, Nikolaeva MN, Lähderanta E, Shevelev VA, Boiko NI. NMR Studies of Carbosilane Dendrimer with Terminal Mesogenic Groups. J Phys Chem B 2010; 114:4159-65. [DOI: 10.1021/jp909658v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Denis A. Markelov
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Vladimir V. Matveev
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Petri Ingman
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Marianna N. Nikolaeva
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Erkki Lähderanta
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Vladimir A. Shevelev
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
| | - Natalia I. Boiko
- Laboratory of Physics, Lappeenranta University of Technology, Box 20, 53851 Lappeenranta, Finland, Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 Russia, Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg, 199004 Russia, Instrument Centre, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014, Turku, Finland, and Faculty of Chemistry, Moscow State University,
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Filip D, Cruz C, Sebastião PJ, Cardoso M, Ribeiro AC, Vilfan M, Meyer T, Kouwer PHJ, Mehl GH. Phase structure and molecular dynamics of liquid-crystalline side-on organosiloxane tetrapodes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:011702. [PMID: 20365386 DOI: 10.1103/physreve.81.011702] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Indexed: 05/29/2023]
Abstract
X-ray diffraction and proton NMR relaxation measurements were carried out on two liquid-crystalline organosiloxane tetrapodes with side-on mesogenic groups, exhibiting nematic and smectic- C phases, and on a monomeric analog. Packing models for the mesophases exhibited by these systems are proposed on the basis of x-ray diffraction data. As a consequence of microsegregation, the aromatic cores are packed in between two sublayers formed by a mixture of interdigitated aliphatic and siloxane chains. The mixed sublayers are characteristic for the tetrapodes with side-on mesogenic groups presented in this work and have not been observed in tetrapodes with terminally attached mesogens. The tilt angle in the smectic- C phase is found very large, i.e., approximately 61 degrees -62 degrees . Notably, smectic- C clusters are present also in the whole temperature range of the nematic phase. NMR relaxometry yields T(1)-1 dispersions clearly different from those of conventional calamitics. The influence of molecular tendency to form interdigitated structures is evidenced by frequency-dependent relaxation rate in the isotropic phase-indicating the presence of ordered clusters far above the phase transition-and by the diminished role of molecular self-diffusion in ordered phases. Nematiclike director fluctuations are the dominating relaxation mechanism whereas the translational displacements are strongly hindered by the interdigitation of dendrimer arms.
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Affiliation(s)
- D Filip
- Centro de Física da Matéria Condensada, Universidade de Lisboa, Lisboa, Portugal
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Domenici V, Cifelli M, Alberto Veracini C, Boiko NI, Agina EV, Shibaev VP. Order and Dynamics of a Liquid Crystalline Dendrimer by Means of 2H NMR Spectroscopy. J Phys Chem B 2008; 112:14718-28. [DOI: 10.1021/jp8003085] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Valentina Domenici
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
| | - Mario Cifelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
| | - Carlo Alberto Veracini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
| | - Natalia I. Boiko
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
| | - Elena V. Agina
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
| | - Valery P. Shibaev
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126, Italy and Chemistry Department, Moscow State University, Moscow 119992, Russia
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