@article{henon_carbonell_desimone_2002, title={Effect of polymer coatings from CO2 on water-vapor transport in porous media}, volume={48}, ISSN={["1547-5905"]}, DOI={10.1002/aic.690480504}, abstractNote={A variety of perfluorinated polyethers were coated onto surfaces of marble, sandstone and limestone samples from solutions in supercritical carbon dioxide. These polymers make ideal protectants for civil infrastructure by making stone surfaces hydrophobic and preventing penetration and deterioration of the stone by acid rain. The effective diffusivities of water vapor through coated and uncoated stones were measured as a function of polymer applied per unit area of sample. An analysis of the diffusive transport of water through the stones led to estimates of the penetration depths of the polymers and the percentages of blockage of the pores in the coated layers as a function of polymer surface coverage. Penetration depths were seen to strongly depend on the mean size and porosity of the stones. It is important for water-vapor diffusion to occur through the samples to prevent water condensation inside polymer-coated structural materials.}, number={5}, journal={AICHE JOURNAL}, author={Henon, FE and Carbonell, RG and DeSimone, JM}, year={2002}, month={May}, pages={941–952} }
 @article{chernyak_henon_harris_gould_franklin_edwards_desimone_carbonell_2001, title={Formation of perfluoropolyether coatings by the rapid expansion of supercritical solutions (RESS) process. Part 1: Experimental results}, volume={40}, ISSN={["0888-5885"]}, DOI={10.1021/ie010267m}, abstractNote={The rapid expansion of supercritical solutions (RESS) process is a promising environmentally benign technology for fine droplet or particle formation. The absence of organic solvents and narrow size distribution of RESS precipitates make this process attractive for polymer coating applications. In our work, this technique has been used to produce droplets of perfluoropolyethers from CO2 solutions without the aid of cosolvents for the coating of porous materials applied in monumental and civil infrastructures. The present work is aimed at gaining an understanding of the relationship between droplet and spray characteristics and RESS process conditions. As such, a combined experimental/computational approach is applied to a representative binary system consisting of a low-molecular-weight perfluoropolyether diamide (PFD) dissolved in supercritical CO2. Part 1 of this work presents phase equilibria measurements and polymer droplet size characterizations under different operating conditions. The effects of temperature, solute concentration, and nozzle configuration on droplet and spray characterization and transfer efficiency are discussed. Part 2 of this work presents a multidimensional computational fluid dynamics model of the RESS expansion process and describes the use of the model in further analyzing and interpreting experimental data.}, number={26}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Chernyak, Y and Henon, F and Harris, RB and Gould, RD and Franklin, RK and Edwards, JR and DeSimone, JM and Carbonell, RG}, year={2001}, month={Dec}, pages={6118–6126} }
 @article{franklin_edwards_chernyak_gould_henon_carbonell_2001, title={Formation of perfluoropolyether coatings by the rapid expansion of supercritical solutions (RESS) process. Part 2: Numerical modeling}, volume={40}, ISSN={["0888-5885"]}, DOI={10.1021/ie010268e}, abstractNote={The rapid expansion of supercritical solutions (RESS) process is a promising method for the production of ultrafine powders and aerosols of narrow size distribution for coatings and other applications. In this article, part 2 of a two-part study, the nucleation and subsequent growth of 2500 Mw perfluoropolyether diamide (PFD) from supercritical carbon dioxide (CO2) by expansion through a small-diameter nozzle is modeled in a three-stage, multidimensional fashion. The stages include a hydrodynamic solution, solvent−solute phase equilibria analyses, and an aerosol transport model. The hydrodynamics model successfully captures the vapor−liquid transition that occurs as carbon dioxide is expanded to ambient conditions. Cloud-point pressures and equilibrium compositions of the separated solvent−solute system are determined and are used in a multidimensional aerosol transport model. This model incorporates various mechanisms influencing droplet growth. Parametric studies are conducted to investigate the influences of the interfacial tension, the equilibrium addition of carbon dioxide, and the diffusion coefficient on the predicted droplet diameter. Turbulent coagulation in the ambient region downstream of the expansion nozzle is found to be the dominant mechanism responsible for the production of micron-sized droplets observed in companion experiments.}, number={26}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Franklin, RK and Edwards, JR and Chernyak, Y and Gould, RD and Henon, F and Carbonell, RG}, year={2001}, month={Dec}, pages={6127–6139} }
 @article{martinache_royer_siripurapu_henon_genzer_khan_carbonell_2001, title={Processing of polyamide 11 with supercritical carbon dioxide}, volume={40}, ISSN={["0888-5885"]}, DOI={10.1021/ie010410b}, abstractNote={The supercritical carbon dioxide induced swelling and plasticization of polyamide 11 were investigated. The swelling kinetics exhibit an initial region of large swelling, in which the diffusion of CO2 into the polymer follows Fickian behavior, and a subsequent region of small volume increase that asymptotically approaches an equilibrium swelling value. The diffusion coefficient of CO2 in polyamide 11 was calculated from the initial slope of the swelling kinetics data. CO2, injected up to 3 wt % using an extrusion rheometer, is shown to be an effective plasticizer for polyamide 11, lowering the viscosity of the polymer melt by as much as 50%. The use of CO2 as a blowing agent was also investigated, and we report preliminary foaming attempts using a batch process. We obtained homogeneously distributed foams, featuring well-defined closed cells with an average diameter of 30 μm that had an unfoamed skin layer.}, number={23}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Martinache, JD and Royer, JR and Siripurapu, S and Henon, FE and Genzer, J and Khan, SA and Carbonell, RG}, year={2001}, month={Nov}, pages={5570–5577} }
 @article{henon_camaiti_burke_carbonell_desimone_piacenti_1999, title={Supercritical CO2 as a solvent for polymeric stone protective materials}, volume={15}, ISSN={["1872-8162"]}, DOI={10.1016/S0896-8446(99)00005-4}, abstractNote={The utilization of CO2 as a potential solvent for fluoropolymers used for the protection of civil infrastructures (buildings, bridges, monuments, etc.) is of major environmental as well as economic importance. The cloud points of six perfluoropolyethers at different weight concentrations in CO2 have been measured over a wide range of pressures. The results show that these fluorinated polymers are readily soluble in pure CO2 (no cosolvent or surfactant needed) at temperatures close to 30°C and pressures below 210 bars. The solubilities of the different polymeric products are strongly depend on the polymer hydrogen content and molecular weight.}, number={2}, journal={JOURNAL OF SUPERCRITICAL FLUIDS}, author={Henon, FE and Camaiti, M and Burke, ALC and Carbonell, RG and DeSimone, JM and Piacenti, F}, year={1999}, month={Jun}, pages={173–179} }