Modeling the Additive Effects of Nanoparticles and Polymers on Hydrogel Mechanical Properties Using Multifactor...

Area of Science:

• Materials Science
• Polymer Chemistry
• Rheology

Background:

• Interpenetrating networks (IPNs) are biomimetic materials used to tailor hydrogel mechanical properties.
• Understanding the rheological behavior of IPNs is crucial for their application in various formulations.
• Acrylamide (AAm) hydrogels with varying crosslinker (Bis), silica nanoparticle (SiNP), and dextran concentrations were investigated.

Purpose of the Study:

• To characterize the rheological behavior of AAm-based single-network and IPN hydrogels.
• To investigate the influence of SiNP and dextran on hydrogel mechanical properties, specifically the saturation modulus.
• To quantify the impact of dextran concentration and molecular weight on IPN viscoelasticity using Han plots.

Main Methods:

• Rheological characterization of AAm hydrogels with varying Bis, SiNP, and dextran concentrations.
• Frequency sweep at 1 Hz and strain sweep at 1% after 90 min gelation.
• Analysis using retrospective 3-level factorial design models and Han plots for multifactor analysis.

Main Results:

• Single-network hydrogels showed a prominent transition at specific Bis concentrations, validated by factorial design models (R² = 0.86).
• IPN hydrogels with dextran exhibited increased elastic (G') and viscous moduli (G") (R² = 0.99).
• Dextran concentration was the most significant factor (R_Dex = 35.3 dB) influencing IPN viscoelasticity, followed by SiNP concentration and dextran MW.

Conclusions:

• Dextran concentration is a key factor in modulating the viscoelasticity of AAm-based IPN hydrogels.
• Han plots provide a systematic method to quantify the effects of thermodynamic properties on rheological transitions in IPNs.
• This study demonstrates a method for tuning hydrogel properties for targeted applications.