Low-density polymer thin film formation in supercritical carbon dioxide
نویسندگان
چکیده
We report a method for producing stable low-density polymer films by using supercritical carbon dioxide (scCO2). Two different molecular weight polystyrene films with various thicknesses were exposed to scCO2 along the density fluctuation ridge in P – T phase diagram. The swollen structures could be then frozen by flash evaporation of CO2 without forming additional voids. X-ray reflectivity data clearly showed that exposure to scCO2 could be used to produce uniform low-density films of about 2Rg thick or less, where Rg is radius of polymer gyration. © 2003 American Institute of Physics. @DOI: 10.1063/1.1629799#
منابع مشابه
Role of Interfacial Interactions on the Anomalous Swelling of Polymer Thin Films in Supercritical Carbon Dioxide
It has recently been shown that thin polymer films in the nanometer thickness range exhibit anomalous swelling maxima in supercritical CO2 (Sc-Co2) in the vicinity of the critical point of CO2. The adsorption isotherm of CO2 on carbon black, silica surfaces, porous zeolites, and other surfaces, is known to exhibit anomalous maxima under similar CO2 conditions. It is believed that because CO2 po...
متن کاملPreparation of PMMA/MWNTs Nanocomposite Microcellular Foams by In-situ Generation of Supercritical Carbon Dioxide
Nanocomposites containing poly(methyl methacrylate) (PMMA) and surface functionalized Multi-Walled Carbon Nanotubes (MWNTs) were synthesized. The dispersion of MWNTs in PMMA was characterized using Transmission Electron Microscopy (TEM).The synthesized nanocomposites were successfully foamed using a simple method based on the in-situ generation of supercritical carbon dioxide (CO2</sub...
متن کاملFlexible low-voltage polymer thin-film transistors using supercritical CO2-deposited ZrO2 dielectrics.
The fabrication of low-voltage flexible organic thin film transistors using zirconia (ZrO(2)) dielectric layers prepared via supercritical fluid deposition was studied. Continuous, single-phase films of approximately 30 nm thick ZrO(2) were grown on polyimide (PI)/aluminum (Al) substrates at 250 °C via hydrolysis of tetrakis(2,2,6,6-tetramethyl-3,5-heptane-dionato) zirconium in supercritical ca...
متن کاملLow Temperature Deposition of Metal Oxide Thin Films in Supercritical Carbon Dioxide using Metal-organic Precursors
A novel chemical route in thin film formation that includes the use of inorganic and organic peroxides and metal organic complexes soluble in supercritical carbon dioxide has been investigated for the deposition of alumina, titania and zirconia thin films at low temperatures (<150°C). The metal organic precursors used include: Al(acac)3, OTi(tmhd)2, and Zr(acac)4. Tert-butyl peroxide, and a 30%...
متن کاملParticle encapsulation with polymers via in situ polymerization in supercritical CO2
Fine Dechlorane (DCR) particles with an average size of 12 Am were successfully encapsulated with poly(methyl methacrylate) (PMMA) and poly(1-vinyl-2-pyrrolidone) (PVP) polymers via in situ dispersion polymerization in supercritical carbon dioxide (scCO2). Adjusting the process parameters can control the coating thickness, surface morphology, and degree of particle agglomeration. A uniform thin...
متن کامل