Related Experiment Video
Updated: Mar 17, 2026
11:17
Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction
Published on: January 19, 2016
23.4K
Communication: Theory of melt-memory in polymer crystallization
1Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA.
The Journal of Chemical Physics
|July 25, 2016
Summary
Polymer crystallization memory effects arise from an intermediate melt state, not just cooling. A new theory explains these phenomena using dissolution and transition temperatures, aligning with experimental data.
Area of Science:
- Polymer Science
- Materials Science
- Physical Chemistry
Background:
- Polymer crystallization from a melt is influenced by the initial melt state, leading to memory effects.
- Unlike small molecules, polymer crystallization memory effects are not solely determined by supercooling.
- This phenomenon has been a long-standing puzzle in polymer science for over five decades.
Purpose of the Study:
- To address the puzzle of melt-memory effects in polymer crystallization.
- To present a theoretical framework explaining the influence of the initial melt state on crystallization.
- To provide analytical formulas for nucleation rate as a function of melt temperature.
Main Methods:
- Introduction of a theory invoking an intermediate inhomogeneous melt state.
- Definition of new parameters: dissolution temperature T1(0) and transition temperature Tt(0).
- Derivation of analytical formulas for nucleation rate based on melt temperature.
Main Results:
- The theory successfully describes melt-memory effects by considering an intermediate inhomogeneous melt state.
- Analytical formulas for nucleation rate are derived as a function of melt temperature.
- The theory is general and applicable to various melt-memory scenarios, depending on melt temperature relative to equilibrium melting temperature.
Conclusions:
- The proposed theory provides a mechanistic explanation for melt-memory effects in polymer crystallization.
- The derived formulas show qualitative agreement with existing experimental data.
- The study offers predictions for future experimental investigations into polymer melt-memory phenomena.
Related Concept Videos
01:21Polymer Classification: Crystallinity
4.2K
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...
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...
4.2K
01:26Polymer Classification: Stereospecificity
3.4K
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...
3.4K
01:10Recrystallization: Solid–Solution Equilibria
4.5K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
4.5K
02:39Phase Transitions: Melting and Freezing
15.5K
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...
15.5K
01:08Molecular Weight of Step-Growth Polymers
3.0K
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...
3.0K
01:25Crystal Growth: Principles of Crystallization
5.7K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
5.7K