Related Experiment Video
Updated: Aug 30, 2025
08:00
DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers
Published on: October 25, 2017
7.0K
Tuning Single-Polymer Growth via Hydrogen Bonding in Conformational Entanglements
Susil Baral1, Chunming Liu1,2, Xianwen Mao1
1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
ACS Central Science
|August 29, 2022
Summary
Synthetic polymer growth is controlled by tuning hydrogen bonding interactions. This study reveals how intra- and intermolecular forces influence polymer dynamics and entanglement, offering new control strategies for polymerization.
Area of Science:
- Polymer Chemistry
- Materials Science
- Physical Chemistry
Background:
- Synthetic polymers are crucial in daily life and advanced materials.
- Controlling polymer synthesis is essential for efficient material design.
- Nonequilibrium conformational entanglements during polymerization influence kinetics and dispersion.
Purpose of the Study:
- To investigate the real-time polymerization dynamics of single polynorbornene-based polymers.
- To systematically tune and study the effect of hydrogen-bonding interactions on polymerization.
- To understand the role of hydroxyl (OH) content in monomer and polymer on polymerization kinetics and dispersion.
Main Methods:
- Utilized magnetic tweezers to perform real-time single-polymer growth measurements.
- Employed ring-opening metathesis polymerization (ROMP).
- Systematically varied the hydroxyl group content in norbornene monomers and polymers, including a nonreactive analogue.
Main Results:
- Demonstrated that intrachain and intermolecular hydrogen bonding compete and affect nonequilibrium entanglements.
- Observed multiphasic dependences of polymerization dynamics on the polymer's OH content.
- Developed a model to quantitatively explain these multiphasic behaviors based on hydrogen bonding interactions.
Conclusions:
- Intra-/intermolecular interactions, polymer conformations, and free monomers interconnectedly affect polymerization kinetics and dispersion.
- Hydrogen bonding provides a tunable mechanism to influence polymer growth dynamics.
- Findings open new avenues for manipulating synthetic polymerization reactions.
Related Concept Videos
01:03Step-Growth Polymerization: Overview
3.6K
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...
3.6K
01:08Molecular Weight of Step-Growth Polymers
2.3K
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...
2.3K
01:17Radical Chain-Growth Polymerization: Chain Branching
2.0K
The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...
2.0K
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
3.4K
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...
3.4K
00:57Cationic Chain-Growth Polymerization: Mechanism
2.4K
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...
2.4K
02:34Polymers
36.4K
The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the...
36.4K