Transparency Change Mechanochromism Based on a Robust PDMS-Hydrogel Bilayer Structure.

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Hydrogels offer biocompatibility and hydrophilicity, while polydimethylsiloxane (PDMS) provides a stable, rigid substrate.
• Combining these materials creates synergistic properties for advanced applications.
• Existing methods often struggle with strong interfacial adhesion between PDMS and hydrogels.

Purpose of the Study:

• To develop a transparent and stretchable covalently bonded PDMS-hydrogel bilayer (PHB) structure.
• To investigate the interfacial adhesion mechanisms between PDMS and hydrogels.
• To create a mechanically responsive surface with mechanochromic properties.

Main Methods:

• In situ free radical copolymerization of acrylamide and allylamine-exfoliated-ZrP (AA-e-ZrP) on a functionalized PDMS surface.
• Utilizing AA-e-ZrP as cross-linking nano-patches within the hydrogel network.
• Constructing covalent bonds via addition reactions between PDMS vinyl groups and monomers.
• Creating a wrinkle surface by adding a cross-linked polyvinyl alcohol film.
• Employing a finite element model to simulate wrinkle formation.

Main Results:

• A transparent and stretchable covalently bonded PDMS-hydrogel bilayer (PHB) structure was successfully prepared.
• Strong interfacial adhesion was achieved through covalent bonding between PDMS and the hydrogel.
• A mechanically responsive wrinkle surface exhibiting transparency change mechanochromism was fabricated.
• The finite element model accurately simulated the wrinkle formation process.

Conclusions:

• The developed covalently bonded PHB structure demonstrates excellent interfacial adhesion and mechanical properties.
• The fabrication method provides a robust approach for integrating PDMS and hydrogels.
• The findings have implications for designing advanced PDMS-hydrogel-based materials, such as the PDMS-hydrogel-PVA trilayer (PHPT) structures.