3D printable soft and solvent-free thermoplastic elastomer containing dangling bottlebrush chains.

Area of Science:

• Polymer Chemistry
• Materials Science
• Additive Manufacturing

Background:

• Bottlebrush polymer networks offer tunable, soft mechanical properties.
• Their implementation in functional processing, like 3D printing, remains limited.

Purpose of the Study:

• To design and develop a novel polydimethylsiloxane (PDMS)-based thermoplastic elastomer for 3D printing.
• To create a solvent-free material with properties suitable for high spatial fidelity additive manufacturing.

Main Methods:

• Synthesized two copolymers: polystyrene-block-bottlebrush polydimethylsiloxane (PS-b-bbPDMS) and polystyrene-block-polydimethylsiloxane-block-polystyrene (PS-PDMS-PS).
• Formulated a blend of these copolymers to create a self-assembling physical network.
• Utilized elevated temperatures for 3D printing without volatile solvents or post-treatment.

Main Results:

• Achieved a soft, solvent-free thermoplastic elastomer with yield stress and rapid recovery.
• Successfully 3D printed self-supportive structures with spanning elements.
• Demonstrated tunability of mechanical properties through molecular design and copolymer ratios (3:1 diblock to triblock).
• Material exhibited a low shear modulus (G' = 3.3 kPa).

Conclusions:

• The developed bottlebrush polymer network is compatible with 3D printing.
• This material enables the creation of complex, soft structures with high fidelity.
• Opens avenues for bottlebrush materials in soft robotics, scaffolds, sensors, and actuators.