Inorganic gyroid with exceptionally low refractive index from block copolymer templating

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Nanoporous materials with ordered structures are crucial for various applications.
• Block copolymers offer a versatile platform for templating nanostructures.
• Degradable polymers enable template removal for creating single-component materials.

Purpose of the Study:

• To fabricate nanoporous polymers with gyroid nanochannels.
• To develop a nanohybrid material with a gyroid silica nanostructure.
• To create a highly porous inorganic gyroid network with a low refractive index.

Main Methods:

• Self-assembly of degradable polystyrene-b-poly(l-lactide) (PS-PLLA) block copolymers.
• Hydrolysis of poly(l-lactide) (PLLA) blocks to create nanoporous polystyrene (PS).
• Sol-gel reaction using nanoporous PS as a template for silica (SiO2) formation.
• UV degradation of the PS matrix to yield the final inorganic gyroid network.

Main Results:

• Successfully fabricated polymers with gyroid nanochannels.
• Obtained a nanohybrid material with a SiO2 gyroid nanostructure within a PS matrix.
• Achieved a highly porous, single-component inorganic gyroid network after PS removal.
• Measured an exceptionally low refractive index (as low as 1.1) for the final material.

Conclusions:

• The self-assembly and degradation strategy is effective for creating complex gyroid nanostructures.
• The resulting inorganic gyroid network exhibits a record-low refractive index.
• This material holds significant potential for applications in low-index coatings and optical devices.