Dendrimers are hyperbranched molecules with well-defined nanometer-scale dimensions. Important technological applications of these systems, both in biomedicine and materials science, have been recently proposed. Liquid crystal dendrimers are fascinating materials that combine the characteristics of dendrimers with the anisotropic physical behaviour and molecular self-organization typical of liquid crystals. This unique association of physical and chemical properties, together with the possibility of multi-selective functionalization put forward by dendrimers, opens new perspectives for applications. Nuclear magnetic resonance (NMR) is a powerful experimental technique applied in materials science and an important tool to the study of molecular organization and dynamics. This book presents an introduction to dendrimers properties with special insight into liquid crystal dendrimers and a detailed description of the NMR theory and experimental techniques used in the investigation of these materials. It also discusses recent NMR research results on liquid crystal dendrimers, with emphasis on molecular order and dynamics studies.
This book introduces the properties of dendrimers, with special insight into liquid crystal dendrimers, and a detailed description of NMR theory and experimental techniques used in the investigation of these materials. It also discusses results of recent NMR research on liquid crystal dendrimers, with an emphasis on molecular order and dynamics studies. Advanced undergraduate and graduate students of physics, chemistry, and materials science and researchers in the fields of dendrimers, liquid crystals, and NMR will find the book extremely useful.
Introduction Dendrimers NMR of Liquid Crystals and Liquid Crystal Dendrimers Liquid Crystals Liquid Crystals Mesophases of Thermotropic Liquid Crystals Molecular Structures of Liquid Crystalline Dendrimers Side-Chain Liquid Crystal Dendrimers Main-Chain Liquid Crystalline Dendrimers Shape Persistent Liquid Crystalline Dendrimers Supramolecular dendromesogens Other Liquid Crystalline Dendrimer Structures Overview Fundamentals of Nuclear Magnetic Resonance Introduction Nuclear Paramagnetism Dynamics of Non-interacting Spins, Bloch Equations The Nuclear Spin Hamiltonian Dynamics of Interacting Spins Pulsed Nuclear Magnetic Resonance NMR spectroscopy of anisotropic fluid systems. Theory and Experimental Introduction Nuclear Spin Hamiltonian for NMR of Anisotropic Fluid Systems Averaged Second Rank Tensorial Quantities and Order Parameters Determination of High Field NMR Absorption Spectra for Selected Spin Systems Quantum mechanical analysis of selected NMR pulse sequences Experimental details NMR relaxation and molecular dynamics. Theory General concepts Relaxation rates Relaxation Mechanisms NMR relaxometry and molecular dynamics. Experimental techniques Inversion-recovery Fast Field-Cycling Experimental Setups NMR spectroscopy of liquid crystal dendrimers. Experimental results NMR of LC dendrimers and the investigation of the biaxial nematic phase Comparison with tetrapode's monomers and other side-chain LC dendrimers NMR relaxometry of liquid crystal dendrimers. Experimental results Liquid crystal dendrimers investigated by NMR relaxometry The influence of dendrimers structure on the molecular dynamics
Carlos R. Cruz received his PhD in physics from the Technical University of Lisbon, Portugal, in 1994. He is a senior lecturer at Instituto Superior Tecnico ( IST) and coordinator of the Complex Fluids NMR and Surfaces Group of CeFEMA (Center of Physics and Engineering of Advanced Materials), Technical University of Lisbon. His research work is mainly focused on liquid crystals experimental physics with particular emphasis on NMR and X-ray diffraction studies. In recent years he has been team leader in two European Projects on liquid crystal dendrimers. Joao L. Figueirinhas received his PhD in physics from Kent State University, Ohio, USA ,in 1987. He is currently a senior lecturer at IST and a researcher at CeFEMA. His main research interests focus on NMR spectroscopy and electro-optics of anisotropic fluids including liquid crystals, polymer liquid crystals and their composites. He has co-authored more than 70 research articles on those subjects. Pedro J. Sebastiao received his PhD in physics from the Technical University of Lisbon in 1993. He is a senior lecturer of physics at IST and a researcher at CeFEMA. His current research interests include NMR study of molecular dynamics in liquid crystals, ionic liquids and other soft matter systems, the development of new fast field cycling NMR technology and model fitting software.