Characterization of Photocurable IP-PDMS for Soft Micro Systems Fabricated by Two-Photon Polymerization 3D Printing.

Area of Science:

• Materials Science
• Microfabrication
• Polymer Science

Background:

• Micro-scale additive manufacturing (AM) enables advanced microelectromechanical systems (MEMS) with soft components.
• Fabricating soft materials at the micro-scale presents challenges.
• IP-PDMS, a soft photocurable polydimethylsiloxane (PDMS) resin, is now available for two-photon polymerization (2PP) AM.

Purpose of the Study:

• To comprehensively characterize the novel IP-PDMS resin for 2PP AM.
• To provide essential material property data for developing microdevices with soft components.
• To report previously undocumented properties of IP-PDMS.

Main Methods:

• Characterization of uncured IP-PDMS: surface tension, contact angle, spin-coating, transmittance, and FTIR.
• Characterization of cured IP-PDMS: mechanical creep, friction, dielectric permittivity, dielectric breakdown strength, contact angle with water, Young's modulus, and viscoelastic properties.
• Utilized both 3D-printed and spin-coated samples for specific measurements.

Main Results:

• Reported novel properties for uncured IP-PDMS, including surface tension (26.7 ± 4.2 mN/m) and contact angle with glass (11.5 ± 0.6°).
• Detailed new characterizations for cured IP-PDMS, such as velocity-dependent friction and high dielectric breakdown strength (up to 73.3 ± 13.3 V/µm).
• Measured key properties of cured IP-PDMS: contact angle with water (103.7 ± 0.5°), Young's modulus (5.96 ± 0.2 MPa), and dielectric permittivity (2.63 ± 0.02).

Conclusions:

• IP-PDMS exhibits promising characteristics for micro-scale soft MEMS applications.
• The comprehensive data facilitates the use of IP-PDMS in microfluidics, storage devices, and smart material technologies.
• This research addresses a critical gap in material characterization for soft microfabrication.