A Layered Polydiacetylene Containing Hydrogen-Bonding 4,4'-Bipyridyl Guests: Reversible Color Changes with a...

Area of Science:

• Materials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Layered organic polymers typically utilize electrostatic interactions for intercalation.
• Polydiacetylene (PDA) polymers exhibit stimulus-responsive color transitions (e.g., blue to red) under thermal or mechanical stress.
• Controlling the dynamic properties and responsiveness of these materials is crucial for applications.

Purpose of the Study:

• To investigate host-guest interactions via hydrogen bonds in layered organic polymers.
• To explore the thermoresponsive color changes of polydiacetylene incorporating hydrogen-bonding guests.
• To expand the operational temperature range and reversibility of PDA color transitions.

Main Methods:

• Synthesis of layered polydiacetylene (PDA) incorporating 4,4'-bipyridyl as an interlayer guest.
• Characterization of host-guest interactions, focusing on hydrogen bonding.
• Thermal analysis and observation of color changes in response to temperature variations.

Main Results:

• Layered PDA with 4,4'-bipyridyl demonstrated host-guest interactions via hydrogen bonds.
• The introduction of the hydrogen-bonding guest significantly altered the thermoresponsive color transition.
• Gradual, two-stage reversible color changes were observed across a broad temperature range (-20–240 °C), unlike the sharp transition at 65 °C in guest-free PDA.
• Weaker interlayer interactions facilitated enhanced dynamic motion, leading to wider temperature responsiveness.

Conclusions:

• Hydrogen-bonding interactions in layered organic polymers can effectively tune thermoresponsive properties.
• The developed PDA system exhibits enhanced dynamic motion and a significantly broadened, reversible temperature range for color changes.
• This work presents a novel approach for designing advanced thermoresponsive materials with tailored functionalities.