Related Experiment Video
Updated: Jul 12, 2025
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
7.2K
Heating-Induced Switching to Hierarchical Liquid Crystallinity Combining Colloidal and Molecular Order in
Lotta Gustavsson1, Zhong-Peng Lv1, Tomy Cherian1
1Department of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland.
ACS Omega
|October 30, 2023
Summary
Zwitterionic molecules form switchable hierarchical self-assemblies in a solvent-free state. This discovery reveals a new type of thermotropic liquid crystallinity with potential for complex material design.
Area of Science:
- Soft Matter Science
- Supramolecular Chemistry
- Materials Science
Background:
- Hierarchical self-assemblies in soft matter are crucial for creating complex, multifunctional materials inspired by biology.
- Achieving such assemblies in a solvent-free state, balancing competing interactions, presents a significant scientific challenge.
Purpose of the Study:
- To investigate the solvent-free self-assembly behavior of zwitterionic bis-n-tetradecylphosphobetaine.
- To explore the potential for thermally switchable hierarchical structures and novel liquid crystalline phases.
Main Methods:
- Synchrotron small-angle X-ray scattering (SAXS) was employed to analyze structural changes.
- Studies were conducted in the solvent-free state, with and without plasticizing ionic liquids.
Main Results:
- Bis-n-tetradecylphosphobetaine exhibits complex, thermally switchable hierarchical self-assembly in the solvent-free state.
- A reversible transition from molecular-level to hierarchical assemblies (combining colloidal and molecular) was observed upon heating.
- The high-temperature phase displays birefringent flow, indicative of a novel hierarchical thermotropic liquid crystalline phase with 2D oblique nanoplatelets.
Conclusions:
- Simple zwitterionic molecules can generate structural hierarchy and tunable complexity in the absence of solvents.
- Balancing electrostatic and nanosegregation interactions is key to controlling self-assembly in bulk soft matter.
- This work introduces a new class of hierarchical thermotropic liquid crystals with potential applications in advanced materials.
Related Concept Videos
01:21Polymer Classification: Crystallinity
2.9K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
2.9K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K
02:54Molecular and Ionic Solids
17.2K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.2K
01:26Polymer Classification: Stereospecificity
2.4K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
2.4K
02:33Phase Transitions: Sublimation and Deposition
17.2K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
17.2K
00:57Cationic Chain-Growth Polymerization: Mechanism
2.3K
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
2.3K