Structure-rheology relationship in polysulfones with triphenylphosphonium pendant groups systems for engineering applications

Ionic polysulfones have received widespread attention for their promising roles in order to create new materials that can modulate the membrane properties. In this context, understanding of mechanisms developed in quaternized polysulfones with triphenylphosphonium pendant groups solutions, considering their specific interactions and the way in which these interactions affect their physical properties were evaluated by rheological investigations. Rheological behavior of this system, described by the non-linear flow curve, indicates the effect of the chemical structure of quaternized polysulfone, in order to facilitate the subsequently preparation of the active membranes. Thus, this study analyzes the processing-property relationship of solutions based on quaternized polysulfones and possibility of using it’s, with expected future developments in the engineering fields

Thermodynamic properties in quaternized polysulfones/neutral polymer/solvent complex systems

Theoretical and experimental aspects concerning the interactions generated via electrostatic interactions and hydrogen-bonding in quaternized polysulfones/neutral polymer/solvent complex ternary systems are investigated. The experimental results related to the intrinsic viscosity and hydrodynamic parameters have been obtained by viscometric measurements, using new Wolf model, and discussed in terms of the chemical structure of compounds, density of charged groups, solution concentrations, and mixing ratio of the two polymers. The conformational changes of the polymer chains in dilute solution as well as the effect of electrostatic interactions, hydrogen bonding or association phenomena are reflected in variations of viscosity function on polysulfone content. Moreover, through the perspective of the new theories approached, this work analyzes the thermodynamic and hydrodynamic functions, making possible choosing of the suitable polymer blends for obtaining membranes with certain applications

Effects of tetraethyl orthosilicate introducing on the rheological properties of celulose acetate solution

The rheological behavior of cellulose acetate (CA)/tetraethyl orthosilicate (TEOS) solution in N,N-dimetilacetamida (DMAc) has been investigated as a function of TEOS content for different shear rates and temperatures. The shear-thinning behavior or so called “pseudoplastic” behavior of the CA pure solution may be caused, on the one hand, by the destruction of the polymer chains as the shear rate increases, and on the other hand, by the increasing of the chains orientation in the flow direction during the rotational measurements. Also, for CA/TEOS blend solutions the curves shape varies from one content to another, a decrease in viscosity as the content of TEOS increases being observed. This tendency, of viscosity decreasing, is mainly due to the formation of hydrogen bonds between -OH groups and Si-OH, characteristic to TEOS, which means that increase in TEOS content tends to form a stable gel network. Furthermore, as temperature increases the viscosity varies irregularly, this being a consequence of the conformational transitions occurring in the system. The incorporation of TEOS in CA solution was described from rheological point view with the aim to produce chemically and mechanically resistant hybrid films with highly degree of dispersed metal particles. Consequently, the present study represents the basis for obtaining hybrid membranes with specific properties, which will find application both in industrial and bioengineering field

Structure-Bioactivity Relationship of the Functionalized Polysulfone with Triethylphosphonium Pendant Groups: Perspective for Biomedical Applications

Development of new biomaterials based on polysulfones tailored to act in various biomedical fields represents a promising strategy which provides an opportunity for enhancing the diagnosis, prevention, and treatment of specific illnesses. To meet these requirements, structural modification of the polysulfones is essential. In this context, for design of new materials with long-term stability, enhanced workability, compatibility with biological materials and good antimicrobial activity, the functionalization of chloromethylated polysulfones with triethylphosphonium pendant groups (PSFEtP+) was adopted. The surface chemistry analysis (Fourier transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX)), rheological properties, morphological aspects (Scanning electron microscopy (SEM), polarized light microscopy (POM)), and antimicrobial activity of the synthetized polysulfone were investigated to establish the relationship between its structure and properties, as an important indicator for targeted applications. Based on the obtained features, evaluated by the relationship between the rheological properties and microstructural aspects, and also the response at the biomaterial-bacteria interface, these qualities have been confirmed in their performance, in terms of thermal stability, antimicrobial activity, and also an increase in lifetime. Consequently, derived results constitute the preliminary basis for future tests concerning their functionality as gel matrices in biomedical devices

Matching the Cellulose/Silica Films Surface Properties for Design of Biomaterials That Modulate Extracellular Matrix

The surface properties of composite films are important to know for many applications from the industrial domain to the medical domain. The physical and chemical characteristics of film/membrane surfaces are totally different from those of the bulk due to the surface segregation of the low surface energy components. Thus, the surfaces of cellulose acetate/silica composite films are analyzed in order to obtain information on the morphology, topography and wettability through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle investigations. The studied composite films present different surface properties depending on the tetraethyl orthosilicate (TEOS) content from the casting solutions. Up to a content of 1.5 wt.% TEOS, the surface roughness and hydrophobicity increase, after which there is a decrease in these parameters. This behavior suggests that up to a critical amount of TEOS, the results are influenced by the morphology and topographical features, after which a major role seems to be played by surface chemistry—increasing the oxygenation surfaces. The morphological and chemical details and also the hydrophobicity/hydrophilicity characteristics are discussed in the attempt to design biological surfaces with optimal wettability properties and possibility of application in tissue engineering

Matching the Cellulose/Silica Films Surface Properties for Design of Biomaterials That Modulate Extracellular Matrix

The surface properties of composite films are important to know for many applications from the industrial domain to the medical domain. The physical and chemical characteristics of film/membrane surfaces are totally different from those of the bulk due to the surface segregation of the low surface energy components. Thus, the surfaces of cellulose acetate/silica composite films are analyzed in order to obtain information on the morphology, topography and wettability through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle investigations. The studied composite films present different surface properties depending on the tetraethyl orthosilicate (TEOS) content from the casting solutions. Up to a content of 1.5 wt.% TEOS, the surface roughness and hydrophobicity increase, after which there is a decrease in these parameters. This behavior suggests that up to a critical amount of TEOS, the results are influenced by the morphology and topographical features, after which a major role seems to be played by surface chemistry—increasing the oxygenation surfaces. The morphological and chemical details and also the hydrophobicity/hydrophilicity characteristics are discussed in the attempt to design biological surfaces with optimal wettability properties and possibility of application in tissue engineering

Metal Ions Removal from Contaminated Water Using Membranes Functionalized with Ionic Liquids

The present work studies the efficiency of new innovative quaternized polysulfone (PSFQ)/ionic liquid (IL) membranes in the treatment process of water containing cadmium ions (Cd(II)). The design and development of the polysulfone membranes with morphology tailored by the use of ILs (Cyphos 101 IL and Aliquat 336) was based on the rheological study of the casting solutions that dictated the optimal compositions of ILs and facilitated the preparation of the membranes for performance tests. Thus, according to the variation of the rheological functions obtained (G′, G″), it was demonstrated that Aliquat 336 has better compatibility with PSFQ, facilitating the workability of the solution and improving the final properties of the membranes relative to Cyphos 101 IL. However, the casting solutions consisting of 5 wt.% Ph-IL and 15 wt.% Am-IL content produce membranes with superior physico-chemical properties. Also, the surface chemistry and morphology analysis of the membranes obtained were investigated in order to understand the relationship between the PSFQ and ILs, as well as their surface properties, as indicators for their future applications. Additionally, the results obtained from the kinetic studies regarding Cd(II) removal from aqueous solutions and the amount of Cd(II) accumulated onto the membranes showed that the ILs enhance the filtration efficiency of the membranes studied and underlined the positive effect of IL in the structure of the quaternized polysulfone membranes. A content of 15 wt.% Aliquat 336 in PSFQ membranes shows the best properties for Cd(II) removal from aqueous solutions; the maximum amount of Cd(II) accumulated on the membrane studied was 3300 mg/m2. This behaviour was maintained for two cycles of washing/filtration, and then the efficiency decreased by 20%. The results obtained showed that the membranes functionalized with ionic liquid could be used efficiently in the treatment of water containing trace concentration of cadmium