Development of superhydrophobic electrospun fibrous membrane of polymers of intrinsic microporosity (PIM-2)

Abstract

Polymers of intrinsic microporosity (PIMs) are increasingly recognized as a potential membrane material for adsorption and separation applications due to their permanent porosity and solution processability. PIM-2 can be produced using commercially available 5,5′,6,6′-Tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane and decafluorobiphenyl monomers in the powder form. It possesses considerable amount of fluorine in the polymer backbone and this feature could provide significant hydrophobicity to polymer. This research aims to investigate the fabrication of self-standing PIM-2 fibrous membranes by electrospinning method to introduce a useful material for adsorption applications. Electrospinning was performed using tetrachloroethane as a solvent and beadfree, uniform fibers were produced as confirmed by SEM imaging. Average fiber diameter was calculated as 5.5 ± 1.5 μm for a self-standing fibrous membrane of PIM-2. Structural characterization was conducted using FT-IR, NMR and XPS spectroscopies showing the purity of pristine powder and fibrous membrane of PIM-2. Thermal stability of PIM-2 fibrous membrane was investigated using TGA and it shows no discernible weight loss below 450°C. The porosity of fibrous membrane was investigated by N 2 adsorption/desorption measurements that indicates significant microporosity with ∼600 m 2 g −1 BET surface area. In addition, the hydrophobicity of PIM-2 was tested by water contact angle measurements, showing 155 ± 6°WCA, indicating superhydrophobicity owing to rough surface and high fluorine content. Consequently, the combination of straightforward synthesis, solution processability, high thermal stability, high surface area, and superhydrophobicity makes PIM-2 a promising candidate for adsorption applications. Therefore, it was successfully employed in organic and oil adsorption. Fibrous membranes of PIM-2 has shown up to 2200 ± 100% and 1900 ± 100% weight gain after in contact with silicon oil and DMSO respectively. In addition, dense membrane of PIM-2 was prepared by solvent casting method and the uptake ability was compared with fibrous membrane showing that fibrous form is more convenient for liquid adsorption applications.

Electrospinning Technique as a Powerful Tool for the Design of Superhydrophobic Surfaces

“…According to this, simply by enhancing the porosity of an electrospun fibers can show a superhydrophobic behavior. This effect of the resultant porosity is evaluated in [41] where the first example of successful production of self-standing fibrous membrane of polymers with intrinsic microporosity (PIM-2) by electrospinning technique is shown, showing a great interest as a potential membrane material for adsorption and separation applications. The fibers are composed of a mixture of 5,5′,6,6´-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane (TTSBI) and decafluorobiphenyl (DFBP).…”

“…TTSBI + DFBP Tetrachloroethane (TCE) Adsorption applications [41] TPU decorated with modified nanosilicas N,N-dimethylformamide (DMF) and tetrahydrofuran (THF)…”

Adsorption of Aniline from Aqueous System by Highly Fluorinated Polymers of Intrinsic Microporosity (PIM-2)

“…Additionally, handling simplicity makes the fiber more practical for real-time applications. Recently, we have synthesised high surface area PIM-2 polymer using commercially available monomers; Decafluorobiphenyl (DFBP) and 5,5',6,6'-Tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane (TTSBI) by improving the previous synthesis method (Sato et al, 2018;Satilmis and Uyar, 2019). PIM-2 is soluble in common laboratory solvents such as tetrahydrofuran, chloroform and tetrachloroethane.…”

“…5,5',6,3,3',3'-tetramethyl-1,1'-spirobisindane (98%, TTSBI) and potassium carbonate (99.0%, anhydrous, K2CO3) were purchased from Alfa Aeser. TTSBI was recrystallized based on the reported procedure (Satilmis and Uyar, 2019). Decafluorobiphenyl (99%, DFBP), methanol…”

Development of One‐Step Water‐Repellent and Flame‐Retardant Finishes for Cotton

“…Technical textiles can be described as the textile products that were manufactured for non‐aesthetic functions, where their roles are the major criterion . The major objective of the technical protective textiles, such as flame‐retardant, antimicrobial and superhydrophobic garments, is to enhance people safety . Cotton is exceedingly flammable fiber in presence of oxygen and heat converting textile materials into gaseous volatiles, which may result in severe damages to the property, such as furniture, residence, vehicle and most significantly human life .…”