Related Experiment Video
Updated: Jan 28, 2026
08:37
Forming, Confining, and Observing Microtubule-Based Active Nematics
Published on: January 13, 2023
3.2K
Nanoparticle-based hollow microstructures formed by two-stage nematic nucleation and phase separation.
Sheida T Riahinasab1, Amir Keshavarz2, Charles N Melton1
1Department of Physics, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA.
Nature Communications
|February 24, 2019
Summary
Researchers developed a novel method for rapidly assembling nanoparticles into hollow microstructures using a two-stage liquid crystal nucleation process. This technique enables tunable formation of foams, shells, and networks for advanced applications.
Area of Science:
- Materials Science
- Nanotechnology
- Soft Matter Physics
Background:
- Rapid assembly of nanoparticles into microstructures is crucial for applications like controlled release, catalysis, and sensing.
- Existing methods face challenges in achieving controlled, large-scale fabrication of nanoparticle assemblies.
Purpose of the Study:
- To report a novel method for forming size-tunable hollow microstructures from nanoparticles.
- To investigate the mechanism of nanoparticle assembly within liquid crystals.
- To control the formation of different hollow structures like foams, shells, and networks.
Main Methods:
- Dispersing mesogen-modified nanoparticles in liquid crystal above the nematic-isotropic transition temperature (TNI).
- Controlled cooling through TNI to induce a two-stage nematic nucleation process.
- Utilizing Cahn-Hilliard simulations to model phase separation dynamics.
- Employing microscopy to analyze the resulting nanoparticle assemblies.
Main Results:
- Successfully formed hollow microstructures including closed-cell foams, spherical shells, and tubular networks.
- Demonstrated that nanoparticle density and cooling rate control structural differentiation and aggregate size.
- Identified second-stage nucleation as a key factor in controlling internal void formation.
Conclusions:
- The reported two-stage nematic nucleation process offers a viable route for rapid, bulk assembly of nanoparticles into diverse hollow microstructures.
- The findings provide insights into controlling nanoparticle self-assembly in liquid crystals.
- This method holds promise for fabricating advanced nanomaterials for various technological applications.
Related Concept Videos
02:39Phase Diagrams
50.0K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
50.0K
01:15Thin-Walled Hollow Shafts
559
In analyzing a thin-walled hollow shaft subjected to torsional loading, a segment with width dx is isolated for examination. Despite its equilibrium state, this segment faces torsional shearing forces at its ends. These forces are quantitatively described by the product of the longitudinal shearing stress on the segment's minor surface and the area of this surface, leading to the concept of shear flow. This shear flow is consistent throughout the structure, indicating a uniform distribution of...
559
02:31Phase Transitions
23.1K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.1K
02:39Phase Transitions: Melting and Freezing
15.0K
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...
15.0K
01:26Stages of Infection
65.2K
Stages of infection describe what happens to a susceptible host once a pathogen invades the human body. The stages of infection are incubation, prodromal, illness, stage of decline, and convalescence. The incubation stage is the period from exposure to a pathogen until symptoms start. The infected person is unaware of impending illness as the pathogens grow and multiply within the body. The duration may vary depending on the type of infection. The incubation period of measles averages ten to...
65.2K
01:28Inductance: Single-Phase And Three-Phase Line
621
Understanding the inductance of transmission lines is crucial for efficient design and operation in electrical power systems. This discussion delves into the inductance characteristics of single-phase two-wire and three-phase three-wire transmission lines with equal phase spacing.
Single-Phase Two-Wire Line:
A single-phase line consists of two solid cylindrical conductors, denoted as x and y. Each conductor carries phasor currents ix and iy, respectively. Given that the sum of these currents is...
Single-Phase Two-Wire Line:
A single-phase line consists of two solid cylindrical conductors, denoted as x and y. Each conductor carries phasor currents ix and iy, respectively. Given that the sum of these currents is...
621