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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 generated carbocation,...

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The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael acceptor.

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Related Experiment Video

Updated: Jul 7, 2026

Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions

Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions

Published on: October 10, 2013

Barrier crossing by a star polymer.

Ananya Debnath¹, K L Sebastian

¹Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|February 1, 2008

Summary

This summary is machine-generated.

We studied star polymers in a double well potential, finding their crossing rate depends on arm length and conformation. Longer polymers may cross barriers faster due to non-monotonic length dependence.

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Area of Science:

Polymer Physics
Statistical Mechanics
Soft Matter Physics

Background:

Star polymers are complex macromolecules with unique dynamic properties.
Understanding polymer dynamics in confined potentials is crucial for materials science.

Purpose of the Study:

To analyze the dynamics of star polymers in a double well potential.
To determine the factors influencing the rate of barrier crossing for star polymers.

Main Methods:

Utilized the continuum Rouse-Adam model for polymer dynamics.
Applied Langer's multidimensional approach to calculate crossing rates.
Solved Newton's equations for independent particles in an inverted potential to find transition states.

Main Results:

Identified a critical barrier curvature determining coiled vs. stretched transition states.
Activation energy shows non-monotonic dependence on star polymer arm length.
Developed methods to handle infinite products in prefactor calculations and resolve rate divergences.

Conclusions:

Star polymer barrier crossing rate is conformation-dependent (coiled vs. stretched).
Non-monotonic dependence of rate on length suggests longer polymers can cross barriers faster.
The study provides a theoretical framework for predicting star polymer dynamics in complex environments.