POSS-hybrid membranes for the removal of sulfur aromatics by pervaporation

Dimensional Nanofillers in Mixed Matrix Membranes for Pervaporation Separations: A Review

Pervaporation (PV) has been an intriguing membrane technology for separating liquid mixtures since its commercialization in the 1980s. The design of highly permselective materials used in this respect has made significant improvements in separation properties, such as selectivity, permeability, and long-term stability. Mixed-matrix membranes (MMMs), featuring inorganic fillers dispersed in a polymer matrix to form an organic-inorganic hybrid, have opened up a new avenue to facilely obtain high-performance PV membranes. The combination of inorganic fillers in a polymer matrix endows high flexibility in designing the required separation properties of the membranes, in which various fillers provide specific functions correlated to the separation process. This review discusses recent advances in the use of nanofillers in PV MMMs categorized by dimensions including zero-, one-, two- and three-dimensional nanomaterials. Furthermore, the impact of the nanofillers on the polymer matrix is described to provide in-depth understanding of the structure-performance relationship. Finally, the applications of nanofillers in MMMs for PV separation are summarized.

Single step synthesis of Janus nano-composite membranes by atmospheric aerosol plasma polymerization for solvents separation

Solvent permeation across membranes is limited due to physical resistance to diffusion from the selective layer within the membrane and to plasticizing effects generated by the solvent molecules onto the polymeric macromolecular matrix. Nano-composite thin film membranes provide promising routes to generate controlled microstructural separation materials with higher selectivities and permeabilities. Here, the fabrication of nano-composite based on octamethyl-polyhedral oligomeric silsesquioxane - hexamethyldisiloxane thin film membranes is demonstrated by aerosol assisted atmospheric plasma deposition onto pre-formed nano-porous membrane supports for the first time. Stable, atomically smooth and continuous solid films with controllable thickness down to 50 nm were achieved. The deposition process allowed for the control of the wettability of the surfaces to water and organic solvents, leading to the generation of hydrophobic but alcohol-philic surfaces. The liquid entry pressure of the films to water was found to be 8 bar from plasma polymerization as oppose to 3 bar for the bare nano-porous support only. In addition, the ideal separation selectivity for ethanol to water, up to 6.5, highlight the impact of both the surface energy and level of cross-linking of the hexamethyldisiloxane nanostructures on the diffusion mechanisms. This new atmospheric plasma deposition strategy opens-up cost-effective and environmentally friendly routes for the design of the smart Janus membrane with customizable properties and performance.

Silsesquioxane polymer as a potential scaffold for laryngeal reconstruction

Cancer, disease and trauma to the larynx and their treatment can lead to permanent loss of structures critical to voice, breathing and swallowing. Engineered partial or total laryngeal replacements would need to match the ambitious specifications of replicating functionality, outer biocompatibility, and permissiveness for an inner mucosal lining. Here we present porous polyhedral oligomeric silsesquioxane-poly(carbonate urea) urethane (POSS-PCUU) as a potential scaffold for engineering laryngeal tissue. Specifically, we employ a precipitation and porogen leaching technique for manufacturing the polymer. The polymer is chemically consistent across all sample types and produces a foam-like scaffold with two distinct topographies and an internal structure composed of nano- and micro-pores. While the highly porous internal structure of the scaffold contributes to the complex tensile behaviour of the polymer, the surface of the scaffold remains largely non-porous. The low number of pores minimise access for cells, although primary fibroblasts and epithelial cells do attach and proliferate on the polymer surface. Our data show that with a change in manufacturing protocol to produce porous polymer surfaces, POSS-PCUU may be a potential candidate for overcoming some of the limitations associated with laryngeal reconstruction and regeneration.

Gold nanoparticle superlattices: structure and cavities studied by GISAXS and PALS

In this study the sizes of cavities formed within the ligand matrix of gold nanoparticle superlattices were probed using positron annihilation lifetime spectroscopy.

Free volume and gas permeation in anthracene maleimide-based polymers of intrinsic microporosity

High free-volume copolymers were prepared via polycondensation with 2,3,5,6,-tetrafluoroterephthalonitrile (TFTPN) in which a portion of the 3,3,3',3'-tetramethyl-1,1'-spirobisindane (TTSBI) of PIM-1 was replaced with dibutyl anthracene maleimide (4bIII). An investigation of free volume using positron annihilation lifetime spectroscopy (PALS), and gas permeation measurements was carried out for the thin film composite copolymer membranes and compared to PIM-1. The average free volume hole size and the gas permeance of the copolymer membranes increased with decreasing TTSBI content in the copolymer.

Preparation and characterization of a PVDF/EG-POSS hybrid ultrafiltration membrane for anti-fouling improvement

The octa vinyl silsesquioxane (OvPOSS) was used to synthesis POSS grafted ethylene glycol (EG) (EG-POSS). The hydrophilicity and anitifouling property of pure PVDF membrane was improved by incorporating EG-POSS in PVDF membrane.