Modeling the formation of double rolls from heterogeneously patterned gels

Area of Science:

• Soft Matter Physics
• Materials Science
• Polymer Science

Background:

• Stimuli-responsive gels and biological tissues exhibit 2D-to-3D morphological transitions.
• Understanding these shape changes is crucial for both technological applications and biological growth processes.

Purpose of the Study:

• To develop an analytical model for predicting 2D-to-3D shape transitions in polymer gels with heterogeneous swelling.
• To quantitatively characterize the morphology of double rolls formed by bistrips of hydrogels with different swelling degrees.

Main Methods:

• Derivation of an analytical model based on the theory of thin incompatible elastic sheets, incorporating Flory-Huggins interactions.
• Quantitative analysis of gel swelling, radii, amplitudes, and transition layer characteristics.
• Validation through comparison with experimental data and nonlinear numerical simulations.

Main Results:

• The analytical model accurately predicts the formation of double rolls with a narrow transition layer between cylinders of constant radii.
• Derived expressions for roll radii, amplitudes, and transition layer length show quantitative agreement with experimental data.
• Numerical simulations confirm the analytical predictions, highlighting stress focusing at material interfaces.

Conclusions:

• The developed model provides quantitative predictions for the morphology of heterogeneously swelling hydrogels.
• This work offers insights into stress focusing at the interface of dissimilar soft materials.
• The findings are applicable to designing advanced gels and understanding biological morphogenesis.