Molecular Templating of Nanoporous Ultralow Dielectric Constant (≈1.5) Organosilicates by Tailoring the Microphase Separation of Triblock Copolymers

Abstract

Triblock polymers, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-b-PPO-b-PEO), are used as molecular templates in poly(methyl silsesquioxane) (MSQ) matrixes to fabricate nanoporous organosilicates. The triblock copolymers microphase-separate into nanometer domains as the MSQ matrix becomes increasingly hydrophobic during a curing step. Extremely small pores (2−5 nm) are generated after thermally removing the template material. These materials attain ultralow dielectric constants (k ≈ 1.5) with electrical and mechanical integrity.

Synthesis of hierarchically porous polymethylsilsesquioxane monoliths with controlled mesopores for HPLC separation

“…Meanwhile, micropores are mainly derived from the removal of F127 that is incorporated in the gel network by hydrogen bonding between silanols and EO units, 20),34), 35) and by hydrophobic interaction between the network and PO units. 36),37) Since the interaction of methylsiloxane polymers with amphiphilic surfactant is not strong, 37), 38) it can be speculated that the incorporated amount of surfactant in the gel network is dominated by the local interaction between PMSQ and surfactant rather than the overall concentration of surfactant in the solution. The change of the amount of surfactant therefore poses virtually no influences on microporosity.…”

Sol-gel synthesis, porous structure, and mechanical property of polymethylsilsesquioxane aerogels

“…Since the hydrophobic interaction between MTMS-derived condensates and F127 molecules works, MTMS-derived condensates mainly adsorb hydrophobic PPO units in polar solvent 32), 33) and the surfaces are made hydrophilic. However, since there exist small number of silanol sites available for the formation of hydrogen bonding and the interaction between the methylated silanol groups (= Si(CH3)(OH)) and the oxygen of PPO units are sterically difficult, hydrogen bonding is formed between PEO units and the MTMS-derived condensates.…”

Intramolecular Cross-linking of Polymers Using Difunctional Acetylenes via Click Chemistry

“…There has been revitalized interest in the preparation of polymeric nanoparticles due to the use of these tailor-made materials in a variety of applications, such as microelectronics [1,2], drug-delivery systems [3][4][5][6][7] and polymer processing [8][9][10]. Recently, several strategies were employed for the preparation of polymeric nanoparticles, including intramolecular cross-linking of single polymer chains containing cross-linkable groups in ultra-diluted reaction conditions [11][12][13][14][15][16][17] and single-chain collapse of macromolecules containing suitable reactive groups along the chain with bifunctional cross-linkers [18,19].…”