Surface grafting thermoresponsive PEO-PPO-PEO chains

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Engineering

Background:

• Thermoresponsive polymers offer tunable surface properties for advanced applications.
• Controlling polymer chain conformation in response to temperature is crucial for smart materials.
• Polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblocks exhibit temperature-dependent behavior in aqueous media.

Purpose of the Study:

• To engineer surfaces with covalently bound, thermoresponsive PEO-PPO-PEO chains.
• To demonstrate the temperature-dependent coiling and uncoiling of grafted polymer chains.
• To explore the potential of these surfaces for applications like tissue engineering and drug delivery.

Main Methods:

• Poly(ethylene terephthalate) (PET) films were functionalized using ammonia plasma to introduce amine groups.
• Hydroxy-terminated PEO-PPO-PEO triblocks were grafted onto the amine-functionalized PET surface using hexamethylene diisocyanate (HDI) as a coupling agent.
• Surface characterization involved X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, and water contact angle measurements.

Main Results:

• XPS confirmed successful nitrogen incorporation (N1s peak at 400.2 eV) after plasma treatment and increased ether C1s peak (286.5 eV) after polymer grafting.
• FTIR spectroscopy and water contact angle measurements corroborated the successful surface modification and polymer attachment.
• The thermoresponsive behavior of the grafted PEO-PPO-PEO chains (P-F127) was confirmed by temperature-dependent water contact angle measurements.

Conclusions:

• A robust method for covalently grafting thermoresponsive PEO-PPO-PEO chains onto PET surfaces was established.
• The engineered surfaces exhibit temperature-dependent conformational changes, demonstrating thermoresponsiveness.
• These functionalized surfaces hold promise for developing advanced materials in biomedical and drug delivery fields.