POSS Core star‐shape molecular hybrid materials: Effect of the chain length and POSS content on dielectric properties

Abstract

A series of inorganic-organic molecular hybrids, poly(styrene-co-octavinyl-polyhedral oligomeric silsesquioxane)s (PS-POSSs), were synthesized, and their structures and properties were characterized by FTIR, 1 H-NMR, 29 Si-NMR, XRD, optical microscopy (OM), and atomic force microscopy (AFM). The chemical incorporation of POSS into polymer matrixes achieves uniform dispersion and makes the resultant hybrids display good film formability. The relationship between molecular structure of these hybrids and their dielectric constants and formation mechanism of low dielectric constant were investigated. The low dielectric constant of the hybrids mainly originates from the increase of free volume, involving the free volume of intrinsic porosity from POSS and an increase in the free volume owing to steric hindrance of bulky POSS. The latter plays a dominant role to increase the free volume and formation of low dielectric constant. Simultaneously, the polymer arm-length has an important influence on the dielectric constant of the star-type hybrids.

Octakis(ethynyldimethylsiloxy) silsesquioxane: Synthesis and application in poly(silicane arylacetylene) resin

“…The reduction of ɛ r is mainly due to the increment in the free volume because of the POSS core and the external porosity introduced by tethering OEMS to the PSA. Ke et al . reported that the contribution of the intrinsic POSS core to the increased free volume is very small compared with the total increased free volume, whereas the steric hindrance of the external porosity plays a dominant role in the growth of free volume and thus reduction of low dielectric constant.…”

Synthesis of composite latexes of polyhedral oligomeric silsesquioxane and fluorine containing poly(styrene‐acrylate) by emulsion copolymerization

“…OvPOSS with eight vinyl groups is easily grafted onto the surface of polymer latexes via one‐step free radical polymerization technique. However, the synthesized composite materials are mainly star‐type rather than network structure due to the steric effect of cage‐like structure of POSS, and those composite materials are soluble in most of the common organic solvents, such as THF, CHCl 3 , dioxane, and toluene . Figure shows the TEM micrographs of the composite latexes.…”

“…The average diameter of FPSA latexes is about 88 nm, while the diameter of OvPOSS/FPSA composite latexes is 95 nm, which is slightly bigger than that of the FPAS, it was probability attribute to the encapsulation of POSS cages, which shown in Scheme . It was reported that POSS cage can promote the crosslinking of the chains to form much denser particles . Therefore, when the OvPOSS content increasing to 1.0%, the average diameter of the composite latex is decreased to 89 nm.…”

“…Many POSS‐based hybrid polymers with different architecture, such as dumbbell‐type, pendent‐type, bead‐type, star‐type, or network‐type, have been prepared and exhibit a number of desirable properties, especially the high thermal stability, good mechanical properties, oxidation resistance, high glass transition temperatures, hydrophobicity, and flammability resistance . POSS‐based polymer and copolymer have being extensively applied to prepare of different kinds of hybrid polymeric materials.…”

POSS‐based molecular hybrids with low dielectric constant: Effect of chemical structure and molecular architecture

“…In particular, the molecular hybrids based on polyhedral oligomeric silsesquioxanes (POSS) that has well defined nanometer‐sized cube‐like structures with porous inorganic core surrounded by eight organic corner groups (active or inert), can effectively overcome the difficulty to disperse the particles into organic/polymer matrix uniformly via covalent bonding . As a result, the incorporation of POSS has led to enhancement in the physical properties of materials such as thermal and mechanical stability, flammability, oxidative resistance, and low dielectric constant . Thus POSS‐based hybrids have been widely studied in many areas of potential use, such as luminescence emission, nonlinear optics, resist coatings for lithography, laser protection, integrated circuits industry as low dielectric constant materials, and so on …”