Thermoreversible hydroferrogels with tunable mechanical properties utilizing block copolymer mesophases as template

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Thermoreversible hydroferrogels (FGs) are advanced materials with tunable properties.
• Pluronic P123 is a triblock copolymer used as a gelator for creating hydrogels.
• Maghemite ferrofluids (FFs) are colloidal suspensions of magnetic nanoparticles.

Purpose of the Study:

• To prepare and characterize thermoreversible hydroferrogels using maghemite ferrofluids and Pluronic P123.
• To investigate the phase behavior and transition temperatures of these hydroferrogels.
• To explore the templating effect of P123 mesophases on magnetic nanoparticles.

Main Methods:

• Gelation of aqueous maghemite ferrofluids with Pluronic P123.
• Rheology and micro-differential scanning calorimetry (μ-DSC) to construct the P123 phase diagram.
• Magnetization experiments to analyze nanoparticle behavior within the hydroferrogels.

Main Results:

• Stable homogeneous hydroferrogels were prepared with maghemite content up to 14 wt % and P123 concentrations of 28-42 wt %.
• Maghemite nanoparticles were effectively templated by cubic and hexagonal P123 mesophases.
• Hydroferrogels exhibited reversible temperature-triggered transitions between cubic and hexagonal phases, with altered mechanical properties (softening).
• Superparamagnetic behavior of maghemite nanoparticles remained unaltered, while cobalt ferrite nanoparticles showed hysteretic behavior.

Conclusions:

• Thermoreversible hydroferrogels can be successfully prepared using maghemite ferrofluids and Pluronic P123.
• The P123 mesophases effectively template magnetic nanoparticles without significantly altering their phase behavior or transition temperatures.
• The developed hydroferrogels demonstrate potential for applications requiring temperature-responsive and magnetically responsive materials.