Data-Driven Printability Modeling of Hydrogels for Precise Direct Ink Writing Based on Rheological Properties

Area of Science:

• Materials Science
• Robotics Engineering
• Polymer Chemistry

Background:

• Hydrogels are increasingly used in soft robotics and electronics due to their mechanical properties and sustainability.
• Three-dimensional (3D) printing of hydrogels is a key fabrication method, but printability is not well understood.
• Rheological behavior is critical for successful hydrogel 3D printing.

Purpose of the Study:

• To quantitatively investigate the relationship between hydrogel rheology and 3D printability.
• To develop a predictive model for hydrogel printability using machine learning.
• To identify key rheological parameters influencing printability for soft robotics and electronics applications.

Main Methods:

• Compilation of a database of 150 3D-printed hydrogels with rheological data.
• Utilized nonlinear rheological metrics, including large-amplitude oscillatory shearing (LAOS).
• Employed machine learning (Random Forest regression) to model printability based on rheological data.

Main Results:

• Developed a predictive model for hydrogel printability with a 10% margin of error.
• Identified that horizontal printability depends on post-extrusion recovery and relaxation.
• Determined that vertical printability is governed by viscous response during high-strain-rate extrusion.

Conclusions:

• Established a quantitative link between hydrogel rheology and 3D printability.
• The findings facilitate the sustainable design of hydrogel inks for advanced manufacturing.
• Enabled precise fabrication of soft robotic and electronic structures through optimized 3D printing processes.