Related Experiment Video
Updated: Jul 20, 2026
08:39
Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles
Published on: October 16, 2017
Dynamics of polymorphic nanostructures: from growth to collapse.
F Carlier1, S Benrezzak, Ph Cahuzac
1Laboratoire Aimé Cotton CNRS, Bât. 505, Université Paris-Sud, 91405 Orsay Cedex, France.
Nano Letters
|September 14, 2006
Summary
Researchers created unique nanoislands by depositing preformed clusters on surfaces. These nanostructures exhibit spectacular flattening collapse processes due to accumulated constraints, offering new insights into surface instabilities.
Area of Science:
- Surface science
- Nanotechnology
- Materials science
Background:
- Controlled deposition of preformed clusters on surfaces enables the construction of complex artificial nanostructures.
- The shape and properties of these nanostructures are highly dependent on cluster size and deposition conditions.
Purpose of the Study:
- To describe methods for generating unusual polymorphic nanoislands.
- To utilize these nanoislands as platforms for exploring instabilities.
- To investigate the role of accumulated constraints in nanostructure evolution.
Main Methods:
- Deposition of preformed clusters onto surfaces.
- Controlled variation of cluster size and surface coverage.
- In-situ observation of nanostructure formation and evolution.
Main Results:
- Generation of unique polymorphic nanoislands with size-dependent shapes.
- Observation of spectacular flattening collapse processes in nanostructures at increased coverage.
- Demonstration that accumulated constraints within nanostructures, rather than substrate constraints, drive collapse.
Conclusions:
- Preformed cluster deposition is a viable route to complex nanostructures.
- Polymorphic nanoislands serve as excellent platforms for studying surface instabilities.
- Internal stress accumulation within nanostructures leads to unique collapse phenomena distinct from substrate-induced effects.
Related Concept Videos
01:03Step-Growth Polymerization: Overview
Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
Many natural and synthetic polymers are produced by...
Many natural and synthetic polymers are produced by...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta catalyst, high molecular...
01:08Molecular Weight of Step-Growth Polymers
Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
01:09Radical Chain-Growth Polymerization: Mechanism
The radical chain-growth polymerization mechanism consists of three steps: initiation, propagation, and termination of polymerization. The polymerization initiates when a free radical generated from the radical initiator adds to the unsaturated bond in the monomer. The unpaired electron of the free radical and one π electron in the unsaturated bond creates a σ bond between the free radical and the monomer. As a result, the other π electron in the unsaturated bond converts this species into the...
01:10Radical Chain-Growth Polymerization: Overview
Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
02:17Microtubule Instability
Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated assembly and...