Orthogonal Monomer Design Enables Sequentially Cured Hybrid Polymers for Ultralow-Dielectric Applications.

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Precise molecular design and orthogonal reaction pathways are crucial for engineering advanced polymer networks.
• Controlled nanoscale architectures and dielectric properties are essential for modern electronic applications.

Purpose of the Study:

• To report an orthogonal monomer design strategy for constructing hybrid polymers with sequentially cured, nanoconfined silsesquioxane (SSQ) domains.
• To achieve precise spatial confinement of SSQ domains within a covalent organic matrix, minimizing defects and phase separation.

Main Methods:

• Integration of ring-opening metathesis polymerization (ROMP), photodimerization, and thermally induced benzocyclobutene (BCB) crosslinking.
• Modular incorporation of photoreactive anthracene and thermally active BCB units into ROMP-compatible monomers for chemically decoupled dual curing.

Main Results:

• The resulting hybrid networks exhibit an ultralow dielectric constant (Dk = 2.08) and extremely low dissipation factor (Df = 6.67 × 10⁻⁴).
• High thermal stability (Td5 > 400°C), hydrophobic surfaces (water contact angle > 100°), and robust mechanical integrity were achieved.
• Sequential crosslinking enabled precise spatial confinement of SSQ domains, minimizing interfacial defects and phase separation.

Conclusions:

• This work highlights a generalizable chemical design paradigm linking orthogonal monomer reactivity to nanoscale structure control.
• The developed hybrid polymers offer a promising pathway for advanced electronic packaging materials with multifunctional dielectric performance.