From hydrophobic to hydrophilic polyvinylidenefluoride (PVDF) membranes by gaining new insight into material's properties

Abstract

a This work provides an easy and versatile strategy to manufacture novel polyvinylidenefluoride (PVDF) membranes by solution casting and phase separation technique displaying tailored physicochemical and microstructural features depending on the opportune combination of functionalization by blending chemical additives (multiwalled carbon nanotubes, MWCNTs) and manufacturing procedure. The systematic study of the effect of (i) polymer concentration, (ii) use of pore forming additive (LiCl), and (iii) type and concentration of MWCNTs, on PVDF crystalline composition and membrane microstructure, highlights the strong relationships of these parameters with the wettability, fouling and transport attributes of the formed membranes. The results provide the key to discriminate membrane preparation conditions favoring hydrophilic, low fouling, and highly selective PVDF-MWCNTs membranes, for water-treatment applications in pressure-driven membrane operations, from conditions favoring the formation hydrophobic and waterproof membranes, to be used in the membrane contactors field. Also, they open exciting perspectives for a more effective development of PVDF-based nanostructured membranes for advanced separations based on a comprehensive investigation and understanding of material properties. 3 Furthermore, surface roughness modulation is known to

Flow reproducibility of whole blood and other bodily fluids in simplified no reaction lateral flow assay devices

“…PVDF membranes can be manufactured to be hydrophilic or hydrophobic depending on the chemical additives and manufacturing procedures that can alter physicochemical and microstructural features of the material. 58 Hydrophilic PVDF is chemical-and temperature-resistant and has low protein binding capability and moderate capillary flow rate, while hydrophobic PVDF has high protein binding capability and minimal capillary flow. 57 In general, filtration membranes have smaller pore sizes ($0.1-5 lm) than lateral flow membranes ($7-15 lm) due to their intended applications.…”

Functionalised Multi-walled Carbon Nanotubes/Cellulose Acetate Butyrate Mixed Matrix Membrane for CO2/N2 Separation

“…This was because the MWCNTs increased the miscibility gap induced by the MWCNTs that work as non-solvent for the polymer (thermodynamic effect on the phase separation, i.e., less water is required to induce phase separation). 34 Besides, a significant change in the structure of the membrane was also observed.…”

Induced Hydrophilicity and In Vitro Preliminary Osteoblast Response of Polyvinylidene Fluoride (PVDF) Coatings Obtained via MAPLE Deposition and Subsequent Thermal Treatment

“…Additionally, the drop-cast PVDF exhibited a lower degree of piezoelectricity comparing to the electrospun equivalent, which was quantified by measuring the intracellular calcium influx. Furthermore, the case of PVDF when the absence of the functional groups on the fluoropolymer, due to low free surface energy, tends to conduct to a deficiency in the cell adhesion and proliferation is well-known [12]. Therefore, considerable efforts have been made for improving the surface hydrophilicity of PVDF polymer by altering the surface chemical composition using various methods: blending the polymer with chemical modifiers [13], plasma treatment, reactive ion etching (RIE) [14,15], etc.…”

“…Because many materials used in surface engineering lack reactive groups for the covalent attachment, hydrophilisation through physical surface modification (e.g., coating with a hydrophilic polymer layer) or chemical treatment (e.g., plasma grafting of polar groups) are used [12]. For these materials, the major challenge of surface engineering is the introduction of reactive groups to the surface [25], the lack of control in the deposited area homogeneity, tailoring the final thickness, expense, and the process being time-consuming.…”