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The Preparation and Characterization of Small Mesopores in Siloxane‐Based Materials That Use Cyclodextrins as Templates
Author(s) -
Yim J.H.,
Lyu Y.Y.,
Jeong H.D.,
Song S.A.,
Hwang I.S.,
HyeonLee J.,
Mah S.K.,
Chang S.,
Park J.G.,
Hu Y.F.,
Sun J.N.,
Gidley D.W.
Publication year - 2003
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200304287
Subject(s) - materials science , silsesquioxane , dielectric , siloxane , porosity , composite material , mesoporous material , coating , chemical engineering , percolation threshold , positronium , thin film , characterization (materials science) , polymer , nanotechnology , organic chemistry , optoelectronics , electrical resistivity and conductivity , chemistry , electrical engineering , physics , quantum mechanics , positron , electron , engineering , catalysis
Porous thin films containing very small closed pores (∼ 20 Å) with a low dielectric constant (∼ 2.0) and excellent mechanical properties have been prepared using the mixture of cyclic silsesquioxane (CSSQ) and a new porogen, heptakis(2,3,6‐tri‐ O ‐methyl)‐β‐cyclodextrin (tCD). The pore sizes vary from 16.3 Å to 22.2 Å when the content of tCD in the coating mixture increases to 45 wt.‐% according to positronium annihilation lifetime spectroscopy (PALS) analysis. It has also been found that the pore percolation threshold (the onset of pore interconnectivity) occurs as the ∼ 50 % tCD porogen load. The dielectric constants ( k = 2.4 ∼ 1.9) and refractive indices of these porous thin films decreased systematically as the amount of porogen loading increased in the coating mixture. The electrical properties and mechanical properties of such porous thin films were fairly good as interlayer dielectrics.