Fabrication and Characterization of Al/ZnO blended Polyvinylidene fluoride (PVDF) membrane via Electrospun Method


S. Gayathri1, K. M. Govindaraju2

1Department of Chemistry, AMET University, Chennai - 603112, India.

2Department of Chemistry, PSG College of Arts and Science, Coimbatore

*Corresponding Author E-mail: prabha.gayathris@gmail.com



Nanofibrous membrane (NFM) of PVDF blended with Al doped nanoZnO was successfully fabricated through electro spinning process. In the present study, the Al doped nanoZnO was synthesized through Sol-gel (SG) route utilizing starch as a stabilizing agent and analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM) with energy dispersive X-ray (EDAX) analysis. Then Atomic Force Microscope (AFM) was utilized to characterize the membrane, and it was found that a stabilized morphology with a size of 300 to 400 nm. Hydrophobic PVDF membrane with a contact angle (CA) 124.700 was prepared by electrospinning of nanoZnO blended PVDF. The CA investigational outcomes of PVDF-ZnO blended membranes demonstrated an enhancement of hydrophilicity with nano ZnO.


KEYWORDS: Nano ZnO, Al doping, PVDF membrane, Electro spinning, AFM.




Interest in wearable piezoelectric materials has developed extremely owing to the growing require for powering mobile devices, attaining sustainable operations, and measuring long-term biometric data1,2. PVDF a common organic membrane material with excellent chemical resistance and thermal stability, has become a hot research topic in the membrane industry3,4. The main disadvantages of PVDF membranes is their hydrophobic environment, causing severe membrane fouling and permeability decline and also, manipulating their uses in water and wastewater treatments5. Upgrading in the membrane hydrophilicity appears to be well-organized method to conquer membrane stinking problem. The positive improvement of nanoparticles incorporated into membranes in water treatment depends on their ability to enhance surface hydrophilicity and water permeability6.



Electro spinning of nanomaterials are gaining increased interest in the fabrication of membrane to filter ultrafine contaminant and degrade the toxic pollutant in waste water treatment.


In the present study, NFM were organized by electrospinning of PVDF solutions. Al doped nano ZnO was synthesized through SG route using starch as a stabilizing agent and analyzed by  XRD, FT-IR and SEM with EDAX analysis. The CA of the membrane was determined to estimate the hydrophobicity nature. The prepared membranes were typified by various physicochemical methods such as SEM, AFM, XRD and EDX.



2.1. Material and methods:

Poly(vinylidenefluoride) (PVDF), Kynar grade 740 was used for the fibre membrane material. The solvent DMAc (Analar grade 99.5%) and polyethylene glycol (PEG) was employed to prepare the polymer solution were purchased from Sigma-Aldrich Co. Zn(CH3COO)2 2H2O, Starch, NH4OH, Ethyl alcohol and AlCl3.H2O were also purchased from Sigma-Aldrich.


2.2 Synthesis of Al doped ZnO:

According to our previous report7, we have synthesized Al doped nano ZnO by the SG method by Zn(CH3COO)2 2H2O and AlCl3.H2O as precursor and starch as a stabilizing agent.


2.3 Preparation of Electrospun PVDF membrane blended Al doped ZnO:

Electrospun PVDF membrane blended Al/ZnO were prepared by according to the previous procedure8 and the electrospinning setup of Zeonics Systech High Voltage D.C. P/S were utilized to develop the PVDF membrane blended Al/ZnO.


2.4 Characterization Techniques:

The crystallinity of the Al/ZnO was examined by XRD technique. The FTIR spectrum was utilized to identify the absorption peaks of the Al/ZnO. The shape, size and morphology were identified by SEM. The elemental analysis was carried out by EDX. The wettability of thin PVDF membrane blended Al/ZnO was concluded by contact angle measurement. Hydrophobic distinctive nature of the samples was expected by contact angle values.



3.1  FT-IR study:

The FT-IR spectrum of the sample are shown in Fig. 1. The band demonstrates accurate peak intensity at 550 cm-1 and 500 cm-1of ZnO and Al/ZnO, respectively. The crests at 1397-1483cm-1 and 690 cm-1 are related to the C-H bending vibrations of CH2, CH3 groups in various stabilising agents. The feature peaks between 3350 - 3788 cm-1 are resulting to the O-H stretching vibration.



Fig. 1 FT-IR spectrum of the ZnO nanoparticles


3.2 SEM and EDX:

The SEM image of Al impregnated ZnO are revealed in Fig.2a. From the results it confirms that the development of ZnO particles size has controlled in Starch. Starch stabilized Al doped ZnO shows the shape of sphere without any agglomeration. The effect of preparative parameter such as pH of the sol, solvents used, on the shape and morphology of particles are studied. EDAX analysis was carried out to identify the clarity and elemental percentage of the sample,. The result indicates that the EDAX spectra (Fig. 3b) shows that sample consists of exclusively Zn = 73 wt% and O = 27 wt%. So, bearing in mind the exposure of elements in the sample, it can be very well careful to have obtained high purity of Al doped ZnO nanomaterial








Fig. 2 (a) SEM image and (b) EDX spectrum of of ZnO nanoparticles

3.3  XRD study:

To know the crystalline nature of the pure and impregnated ZnO nanoparticles were identified by utilizing XRD. Fig. 3 illustrates the diffraction pattern of ZnO nanoparticles which clearly shows hexagonal wurtzite structure and also demonstrations the occurrence of a peak related to a Zn spinel phase of Al doped ZnO.



Fig. 3 XRD pattern of pure and doped ZnO nanoparticles


3.4  FESEM of PVDF/ZnO:

Fig.4 presents the FESEM images of PVDF blended Al doped ZnO. The fibers in PVDF/ZnO are interconnected with a large number of fibres of different sizes (Fig. 4a &4b). The average diameter of the fibers of PVDF/ZnO increases with increasing dopant content in the composite. However, the fibers of PVDF/ZnO have uniform diameters of about 300-400 nm and smooth surface (Fig. 4a). It is important to note that there is less bead formation under the conditions selected by us for the electro spinning9,10.



Fig. 4 FESEM images of PVDF blended Al doped ZnO


3.5  AFM study:

The AFM images reveal that the nature of the dopant manipulates the structure of the membrane. The doped ZnO membrane roughness is higher (Average Roughness, Sa-163.143 nm), As it can be seen, all the PVDF blended ZnO membrane are dense without beads (Fig. 5).


Fig. 5AFM image of PVDF blended ZnO membrane


3.6 Contact angle measurement studies

Vibrant CA analysis was carried out to evaluation the hydrophobicity of membranes. Pure PVDF membrane demonstrated a first water CA of 118° (Fig. 6). Before the Al doped ZnO nanomaterial was added in cast solution, the initial value of water contact angle increased to 124.70°.  By the small addition of Aluminium to the ZnO nano particle blending with PVDF cast solution clarified that aluminium nanoparticles can provide PVDF membrane with excellent surface hydrophilicity in this study11-13






Pure PVDF  

Fig. 6 CA measurement of PVDF blended ZnO membrane



In the present study, nanofibre membranes were prepared by electrospinning of PVDF solutions with Al doped ZnO content, which displayed a absorbent morphology formed in nanoscale..The SEM results indicated that the addition Al/ZnO illustrates the formation of spherical and the percentage composition of the material was analyzed by EDAX. The result indicates that the EDAX spectra shows that sample consists of completely Zn = 73 wt% and O=27 wt% and remaining of Al content. FESEM images show the average diameter of the PVDF blended Al doped ZnO fibers which increases with increasing dopant content in the composite. The AFM images reveal the doped ZnO membrane roughness is higher (Average Roughness, Sa-163.143 nm). The membrane hydrophilicity, porosity, thermal stability and water flux were increased due to the introduction of aluminium doped with nano ZnO. From this we conclude that the introduction of aluminium doped with nano ZnO plays a vital role for the formation of nanofibers membrane by electrospinning method.



Author would like to thank to PSG College of Technology, Peelamedu, Coimbatore, India.



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Received on 02.10.2018            Modified on 20.10.2018

Accepted on 03.11.2018           © RJPT All right reserved

Research J. Pharm. and Tech 2019; 12(2):787-790.

DOI: 10.5958/0974-360X.2019.00137.9