Engineering Ultraporous and Highly Stable Polyacrylonitrile/Poly(vinyl alcohol) Sponges with High Water Absorption...

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Ultraporous sponges are crucial for liquid absorption in diverse applications.
• Developing materials with high water absorption capacity is an ongoing research challenge.

Purpose of the Study:

• To synthesize and characterize ultraporous polyacrylonitrile/poly(vinyl alcohol) (PAN/PVA) sponges.
• To investigate the mechanical properties and morphological changes of these sponges under tensile stress.

Main Methods:

• Four-stage process: electrospinning, short fiber suspension creation, freeze-drying, and PVA cross-linking with varying maleic anhydride (MA) concentrations.
• Characterization using electron microscopy, X-ray microscopy, and mechanical testing.
• In situ tensile testing within a micro-CT scanner coupled with digital volume correlation analysis.

Main Results:

• Achieved sponges with 90% porosity, 0.4 μm average fiber thickness, and up to 16000% water absorption capacity.
• Wet sponges exhibited increased compliance and elongation compared to dry sponges.
• In situ analysis revealed significant morphological changes, strain localization, and identified fracture-prone regions during stretching.

Conclusions:

• The study presents an efficient strategy for producing lightweight, hydrophilic PAN/PVA sponges with exceptional water absorption.
• The findings offer insights into the mechanical behavior and failure mechanisms of these ultraporous materials.
• The developed sponges are suitable for applications in water management, biomedical devices, and tissue engineering.