The use of amphiphilic macrosurfactants as emulsifying agents has shown to have higher efficiency than that of low molecular weight surfactants. Compared to traditional surfactants, polymeric surfactants have lower critical micelle concentrations and lower diffusion coefficients. In this paper, we present a well defined copolymer based on lauryl methacrylate and poly(ethylene glycol) methyl ether methacrylate, prepared by solution radical copolymerization. The product was characterized by NMR and FTIR spectroscopies and the weight-average molecular weight and polydispersity index were analyzed by SEC. The thermal transitions and decomposition temperatures of the copolymers were determined by DSC and TGA, respectively. Due to the hydrophobic and hydrophilic nature of the monomer units, emulsification studies were performed. DLS experiments showed different sizes of the formed micelles depending on solvent polarity due to polymer-polymer or polymer-solvent interactions. Rheological characterization was undertaken to study the viscoelastic properties of the dispersed systems. Finally, two types of experiments to evaluate the polymer abilities as surfactant have been carried out. Firstly, the amphiphilic characteristics of this material allowed the incorporation of small amounts of an organic solvent in water forming only one phase, as well as the incorporation of small amounts of water in the organic solvent forming an emulsified phase. Then, the amphiphilic properties of this macrosurfactant have been fully exploited in order to form highly stable dispersions of carbon nanotubes in water.
This work reports on an ovel and versatile approach to control the structure of metal-organic framework (MOFs)f ilms by using polymeric brushes as 3D primers, suitable for triggering heterogeneous MOF nucleation.A sa proof-of-concept, this work explores the use of poly(1-vinylimidazole) brushesprimerobtained via surface-initiateda tom transferr adical polymerization (SI-ATRP) for the synthesis of Zn-based ZIF-8 MOF films. By modifying the grafting density of the brushes,s mooth porousf ilms were obtained featuring inherently hydrophobic microporosity arising from ZIF-8 structure, and an additional constructional interparticle mesoporosity,w hich can be employed for differential adsorption of targeted adsorbates. It was found that the graftingd ensity modulatest he constructional porosity of the films obtained; higherg rafting densities result in more compact structures,w hile lower grafting density generates increasingly inhomogeneous films with ah igherp roportion of interparticleconstructional porosity.
We studied the complex interaction between polyNIPAm-based microgels and a positively charged polyelectrolyte. Also, the microgels were loaded with doxorubicin and its release was evaluated as a function of the polyelectrolyte molecular weight.
ZIF‐8 (based on Zn and 2‐methylimidazole) MOF film growth can be controlled by using SI‐ATRP‐synthesized polymeric brushes as 3D primers. This strategy relies on the inclusion of chemical moieties in the brush, which are compatible with MOF chemical structure. According to such criteria, Poly(1‐vinylimidazole) brushes with increasingly higher grafting densities were selected. Aside from the inherently hydrophobic microporosity arising from ZIF‐8 structure, our approach renders control over the proportion of constructional mesoporosity, which allow differential adsorption. More information can be found in the Full Paper by O. Azzaroni, M. Rafti, et al. on page 12388.
Multiphase aqueous-organic systems where a bicontinuous phase is in equilibrium with an excess organic and aqueous phase find various applications in industry. These systems�also known as Winsor III�are complex not only for the different phases that develop therein but also because they are multicomponent systems. In this work, we explore for the first time the use of a benchtop low-field single-sided NMR to determine the species distribution in Winsor III systems. The proposed methodology provides information at macroscopic and microscopic levels. In particular, we show the use of single-sided NMR to determine the phases' dimensions and the species distribution in a polymer-based bicontinuous system. The phases' dimensions and limits can be resolved with micrometric precision and are indicative of the bicontinuous phase stability. The species distribution is determined by means of spatially resolved NMR relaxation and diffusion experiments. It was observed that the salinity of the aqueous phase also impacts the species distribution in the bicontinuous system. Experiments show that the additive and the polymer are mainly located in the bicontinuous phase. As the salinity of the aqueous phase increases, the amount of organic components in the bicontinuous phase decreases as a consequence of the species distribution in the system. This influences the total amount of recovered organic liquid from the organic phase. The information is obtained in a relatively fast experiment and is relevant to the system's possible applications, such as enhanced oil recovery (EOR). This methodology is not only circumscribed to its application in EOR but can also be applied to the study of any emulsion or microemulsion systems without sample size or geometry constraints.
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