Programmable and Spatial Stiffness Gradient Substrates for Highly Robust Artificial Skins.

Area of Science:

• Materials Science
• Robotics
• Wearable Technology

Background:

• Stretchable artificial skins are crucial for human-machine interaction and equipment monitoring.
• Achieving robust sensing performance under mechanical deformation is challenging due to material mismatch and complex fabrication.

Purpose of the Study:

• To develop an easy fabrication strategy for substrates with spatial and programmable stiffness gradients.
• To enhance the robustness and reduce strain interference in stretchable artificial skins.

Main Methods:

• Fabrication of a polydimethylsiloxane (PDMS) substrate with stiffness gradients using direct writing and laser gelation.
• Integration of sensing elements onto stiffer regions of the substrate.
• Characterization of stiffness variation (up to 10-fold), adhesion, and durability.

Main Results:

• The stiffness gradient effectively inhibited strain effects from stretching and bending on sensing elements.
• Prototypes demonstrated robust performance of integrated sensors and light-emitting diodes during dynamic deformations.
• The fabricated substrates exhibited excellent adhesive properties and durability.

Conclusions:

• The proposed method offers an efficient pathway for fabricating robust stretchable electronics.
• This approach is particularly promising for real-time health surveillance applications.
• Spatial stiffness gradients significantly improve the mechanical robustness of artificial skins.