Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Polymer Classification: Stereospecificity01:26

Polymer Classification: Stereospecificity

2.7K
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...
2.7K
Polymer Classification: Crystallinity01:21

Polymer Classification: Crystallinity

3.2K
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...
3.2K
Anionic Chain-Growth Polymerization: Overview01:20

Anionic Chain-Growth Polymerization: Overview

2.2K
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
2.2K
Cationic Chain-Growth Polymerization: Mechanism00:57

Cationic Chain-Growth Polymerization: Mechanism

2.5K
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...
2.5K
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

2.4K
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...
2.4K
Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

4.0K
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
4.0K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Time-staggered chemo-immunotherapy via engineered nanofiber resists postoperative dynamic immunosuppression in glioblastoma.

Nature communications·2026
Same author

Hyperbranched dielectric polymer networks exhibiting giant energy storage density at 250 °C.

Nature communications·2026
Same author

Loss of PINK1 causes age-dependent mitochondrial trafficking deficits in nigrostriatal dopaminergic neurons via aberrant p38 MAPK activation.

NPJ Parkinson's disease·2026
Same author

Mechanoelectrical metamaterials for broad-range, high-sensitivity pressure sensing.

Science (New York, N.Y.)·2026
Same author

Down-Feather-Inspired Cellulose/Chitin Coaxial Cryogel Fibers with Triple Barriers for Thermal Insulation Textiles.

Biomacromolecules·2026
Same author

Agar-modified gelatin/polyvinyl alcohol-based tough hydrogels for 3D printing to prepare multifunctional sensors and flexible supercapacitors.

Carbohydrate polymers·2026
Same journal

The BRCA1-A complex restricts replication fork reversal-dependent DNA repair in ATM deficient cells.

Nature communications·2026
Same journal

Signaling downstream of tumor-stroma interaction regulates mucinous colorectal adenocarcinoma apicobasal polarity.

Nature communications·2026
Same journal

Click-polymerized polyenamine membranes for efficient lithium extraction.

Nature communications·2026
Same journal

Joint trajectories of brain atrophy, white matter hyperintensities and cognition quantify brain maintenance.

Nature communications·2026
Same journal

Proton shuttling at electrochemical interfaces under alkaline hydrogen evolution.

Nature communications·2026
Same journal

metilene<sup>3</sup>: identifying DMRs across multiple conditions with auto-classification.

Nature communications·2026
See all related articles

Related Experiment Video

Updated: Oct 7, 2025

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation
11:11

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Published on: May 2, 2016

11.2K

Solid-state cooling by elastocaloric polymer with uniform chain-lengths.

Shixian Zhang1, Quanling Yang1, Chenjian Li1

  • 1State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, and School of Materials Science and Engineering, Wuhan University of Technology, 430070, Wuhan, China.

Nature Communications
|January 11, 2022
PubMed
Summary
This summary is machine-generated.

Researchers developed advanced polymer elastomers with uniform molecular chains, significantly boosting the elastocaloric effect for efficient solid-state cooling. This breakthrough could lead to commercial elastocaloric refrigeration devices.

More Related Videos

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction
11:17

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

Published on: January 19, 2016

22.2K
Microfluidic Preparation of Liquid Crystalline Elastomer Actuators
12:04

Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

Published on: May 20, 2018

9.1K

Related Experiment Videos

Last Updated: Oct 7, 2025

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation
11:11

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Published on: May 2, 2016

11.2K
Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction
11:17

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

Published on: January 19, 2016

22.2K
Microfluidic Preparation of Liquid Crystalline Elastomer Actuators
12:04

Microfluidic Preparation of Liquid Crystalline Elastomer Actuators

Published on: May 20, 2018

9.1K

Area of Science:

  • Materials Science
  • Thermodynamics
  • Polymer Science

Background:

  • The elastocaloric effect, observed in natural rubber over 160 years ago, has potential for solid-state refrigeration.
  • Commercialization of elastocaloric cooling using polymer elastomers has been limited by insufficient effects and high extension ratio requirements.

Purpose of the Study:

  • To demonstrate significantly enhanced elastocaloric effects in polymer elastomers with uniform molecular chain lengths.
  • To develop a strategy for improving elastocaloric performance in polymers for practical cooling applications.

Main Methods:

  • Synthesizing poly(styrene-b-ethylene-co-butylene-b-styrene) with controlled molecular chain lengths.
  • Characterizing the elastocaloric properties, including adiabatic temperature and isothermal entropy changes.
  • Designing and testing a rotary-motion cooling device optimized for rubber materials.

Main Results:

  • Achieved a substantial adiabatic temperature change of -15.3 K and an isothermal entropy change of 145 J kg-1 K-1 near room temperature.
  • Demonstrated that uniform molecular chain lengths in polymer elastomers lead to enormous, reversible elastocaloric effects.
  • Successfully tailored a rotary-motion cooling device to leverage the high-strain capabilities of the developed elastomers.

Conclusions:

  • Uniform molecular chain lengths are crucial for maximizing elastocaloric effects in polymers.
  • The developed polymer elastomers show superior performance compared to previously reported materials.
  • This research offers a viable strategy for commercializing polymer elastomer-based solid-state cooling devices.