Temperature Responsive Copolymers Films of Polyether and Bio-Based Polyamide Loaded with Imidazolium Ionic Liquids for Smart Packaging Applications

Temperature-responsive materials are highly interesting for temperature-triggered applications such as drug delivery and smart packaging. Imidazolium Ionic Liquids (ILs), with a long side chain on the cation and a melting temperature of around 50 °C, were synthetized and loaded at moderate amounts (up to 20 wt%) within copolymers of polyether and a bio-based polyamide via solution casting. The resulting films were analyzed to assess their structural and thermal properties, and the gas permeation changes due to their temperature-responsive behavior. The splitting of FT-IR signals is evident, and, in the thermal analysis, a shift in the glass transition temperature (Tg) for the soft block in the host matrix towards higher values upon the addition of both ILs is also observed. The composite films show a temperature-dependent permeation with a step change corresponding to the solid-liquid phase change in the ILs. Thus, the prepared polymer gel/ILs composite membranes provide the possibility of modulating the transport properties of the polymer matrix simply by playing with temperature. The permeation of all the investigated gases obeys an Arrhenius-type law. A specific permeation behavior, depending on the heating-cooling cycle sequence, can be observed for carbon dioxide. The obtained results indicate the potential interest of the developed nanocomposites as CO₂ valves for smart packaging applications.

A Review of the Recent Progress in the Development of Nanocomposites Based on Poly(ether-block-amide) Copolymers as Membranes for CO2 Separation

An inspiring challenge for membrane scientists is to exceed the current materials' performance while keeping the intrinsic processability of the polymers. Nanocomposites, as mixed-matrix membranes, represent a practicable response to this strongly felt need, since they combine the superior properties of inorganic fillers with the easy handling of the polymers. In the global strategy of containing the greenhouse effect by pursuing a model of sustainable growth, separations involving CO2 are some of the most pressing topics due to their implications in flue gas emission and natural gas upgrading. For this purpose, Pebax copolymers are being actively studied by virtue of a macromolecular structure that comprises specific groups that are capable of interacting with CO2, facilitating its transport with respect to other gas species. Interestingly, these copolymers show a high versatility in the incorporation of nanofillers, as proved by the large number of papers describing nanocomposite membranes based on Pebax for the separation of CO2. Since the field is advancing fast, this review will focus on the most recent progress (from the last 5 years), in order to provide the most up-to-date overview in this area. The most recent approaches for developing Pebax-based mixed-matrix membranes will be discussed, evidencing the most promising filler materials and analyzing the key-factors and the main aspects that are relevant in terms of achieving the best effectiveness of these multifaceted membranes for the development of innovative devices.

Structural investigation and application of Tween 80-choline chloride self-assemblies as osmotic agent for water desalination

Forward osmosis (FO) process has been extensively considered as a potential technology that could minimize the problems of traditional water desalination processes. Finding an appropriate osmotic agent is an important concern in the FO process. For the first time, a nonionic surfactant-based draw solution was introduced using self-assemblies of Tween 80 and choline chloride. The addition of choline chloride to Tween 80 led to micelles formation with an average diameter of 11.03 nm. The ¹H NMR spectra exhibited that all groups of Tween 80 were interacted with choline chloride by hydrogen bond and Van der Waals’ force. The influence of adding choline chloride to Tween 80 and the micellization on its osmotic activity was investigated. Despite the less activity of single components, the average water flux of 14.29 L m^‒2 h^‒1 was obtained using 0.15 M of Tween 80-choline chloride self-assembly as draw solution in the FO process with DI water feed solution. Moreover, various concentrations of NaCl aqueous solutions were examined as feed solution. This report proposed a possible preparation of nonionic surfactant-based draw solutions using choline chloride additive with enhanced osmotic activities that can establish an innovative field of study in water desalination by the FO process.

Nano-vesicular formulation of propolis and cytotoxic effects in a 3D spheroid model of lung cancer

BACKGROUND

Propolis exhibits therapeutic properties due to the presence of phenolic acids, esters, and flavonoids. The scope of this study was to develop a nano-vesicular formulation and establish a three-dimensional (3D) spheroid model in which lung cancer is recapitulated.

RESULTS

Niosome vesicles doped with galangin-rich propolis extract were synthesized by the ether injection method using a cholesterol : surfactant mass ratio of 1 : 3 at 40 °C for 1 h. Formulated niosomes were administered to 3D lung cancer spheroid model and the cytotoxicity was compared with that of a two-dimensional (2D) setting. The galangin content was determined as 86 μg mg^-1 propolis extract by ultra-performance liquid chromatography (UPLC). The particle size of loaded niosome was 151 ± 2.84 nm with a polydispersity index (PDI) of about 0.232, and an encapsulation efficiency of 70% was achieved.

CONCLUSION

The decrease in cell viability and the scattering in the 3D spheroids of A549 lung cancer cells treated with propolis-loaded niosomes were notable, indicating a profound cytotoxic effect and suggesting that they can be utilized as an effective nano-vesicle. © 2020 Society of Chemical Industry.

Enhancing Gas Permeation Properties of Pebax® 1657 Membranes via Polysorbate Nonionic Surfactants Doping

Composite membranes were prepared by co-casting, incorporating two nonionic surfactants in a poly(ether-block-amide), Pebax® 1657 up to 50 wt %. These polysorbate nonionic surfactants contain many ethylene oxide units and are very CO2-philic agents; thereby, they can be exploited as membrane additives for gas separation involving carbon oxide. Dynamic light scattering analysis proved a higher stability of additionated Pebax® 1657 solutions with respect to those containing only the copolymer. Scanning electron microscopy showed a regular membrane morphology without pores or defects for all investigated samples. If on the one hand the addition of the additive has depressed the mechanical properties, on the other, it has positively influenced the gas transport properties of Pebax® 1657 films. CO2 permeability increased up to two or three times after the incorporation of 50 wt % additive in copolymer matrix, while the selectivity was not significantly affected. The effect of temperature on permanent gas transport properties was studied in the range of 15-55 °C.

Study on the synthesis and properties of an eco-friendly sugar-based anionic–nonionic surfactant

An eco-friendly surfactant (DAGA-ES) was successfully synthesized and characterized by electrospray ionization-time of flight mass spectrography (ESI-TOFMS),¹H nuclear magnetic resonance (¹HNMR) and Fourier transform infrared spectrometer (FT-IR).

Enhanced CO2 separation performance of P(PEGMA-co-DEAEMA-co-MMA) copolymer membrane through the synergistic effect of EO groups and amino groups

PEDM copolymer membrane showed excellent gas separation performance through synergistic effect of EO and amino.

Efficient CO2 capture by metallo-supramolecular polymers as fillers to fabricate a polymeric blend membrane

Novel fillers based on metallo-supramolecular polymers were incorporated into PEBA2533 to obtain blend membranes, showing excellent CO₂ permeability and CO₂/N₂ selectivity.