Morphological Investigation of Electrospun Nanofibers Cellulose

Acetate-based Membrane

Aditia Warman

, Hamonangan Nainggolan

, Mahyuni Harahap

, Dellyansyah

, Grace Nainggolan

Suhut Alexander Situmorang

, Saharman Gea

Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Jalan Bioteknologi

Padang Bulan, Medan, 20155, Sumatera Utara,Indonesia

Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Jalan Bioteknologi

Padang Bulan, Medan, 20155, Sumatera Utara,Indonesia

Postgraduate Chemistry Study Program, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara,

Jalan Bioteknologi Padang Bulan, Medan, 20155, Sumatera Utara,Indonesia

Keywords: Nanofibers, Electrospinning, Cellulose Acetate, Membrane, Morphology

Abstract: Electrospinning technique had been used to produce ultra-fine fiber with diameter in nano-scale by dissolving

polymer precursor in suitable solvents. In this study, electrospinning was used to produce cellulose acetate

nanofibers with distance 20 cm, flowrate 0.10-0.15 ml/h and voltage 8 kV. Cellulose acetate was dissolved in

acetone:DMSO (2:8 and 3:7). The morphologies of the spun fibers were investigated using a scanning electron

microscope (SEM). The functional group of the fibers was analyzed using a Fourier Transform Infrared

(FTIR). The result of FTIR showed that C=O functional group at wavenumber 1751 cm

-1

. The morphology

of cellulose acetate dissolved in acetone:DMSO (3:7) wassmoother than acetone:DMSO(2:8).

1 INTRODUCTION

About the population of the world, 11% of themis

lack clean water access. The World health

Organization (WHO) in 2012 anticipates that the

shortage of clean water can involve with 4 million

lives by 2050. Although water consists of more than

70% on earth surface, 97% is sea water (Shirazi,

Kargari and Shirazi, 2012). In addition, almost 3% of

the water stuck in the ground or inside glaciers and

ice. Hence, the world only leaves less than 1% of

water that can be depleted, the desire of gaining more

productive and economical water filtration and

cleaning methods are required to raise demand for

water.

Membrane-based technology has gained

popularity for more than a last century due to its high

separation efficiency, inexpensive and easy to

operate. The membrane work on principle two phases

separation which only let the phase with suitable size

of membrane porous. Membrane can be classified

into porous and dense depending of their structure

(Takht Ravanchi, Kaghazchi and Kargari, 2009). The

nature of membrane transport and selectivity depends

heavily on the structure of its porous (Ahmed, Lalia

and Hashaikeh, 2015).

Nanofibers are part of a nanomaterial which has

very unique and interesting properties due its

nanoscale diameters and large aspect ratio(Huang et

al., 2003). They can be produced by various

technique such as synthesis templates, phase

separation(Ichimori et al., 2013), self-assembly,

steam-explosion(Gea et al., 2018), and

electrospinning(Arkoun et al., 2017). Among three of

them, electrospinning develops significantly due its

simple and reliable technique for converting various

polymer into with controllable morphology(Ahmed,

Lalia and Hashaikeh, 2015) .Electrospinning is a

technique used to produce a continuous of nanofibers

in non-woven form. The process spinning fibers

diameters ranging from 80 to several hundred

nanometers. The report on electrospinning

continuous to increase due to its efficient equipment

and usage, simple, fast and economical (Daels et al.,

2011).

One of nanofiber applications is water filtration.

For flat-shaped nanofiber, it can be applied as a water

filtration membrane or microfiltration. Due to the

higher porosity and interconnected open pore

Warman, A., Nainggolan, H., Harahap, M., Dellyansyah, ., Nainggolan, G., Alexander Situmorang, S. and Gea, S.

Morphological Investigation of Electrospun Nanoﬁbers Cellulose Acetate-based Membrane.

DOI: 10.5220/0010152000002775

In Proceedings of the 1st International MIPAnet Conference on Science and Mathematics (IMC-SciMath 2019), pages 267-272

ISBN: 978-989-758-556-2

267

structure provide higher permeability properties for

filtration of water than conventional materials

(Bjorge et al., 2009). The purpose of this study is to

produce electrospun nanofiber membranes of

cellulose acetate and investigate its morphology.

Cellulose acetate is an easily dissolved polymer in

acetone, but the acetone is highly volatile with a

boiling point of about 56ºC. In electrospinning the use

of volatile solvent causes the fibers to evaporate

before reaching the collector, it would block the tip of

the needle and stop the spinning process(Son et al.,

2004). Thus, acetone needs to be lowered in its

volatility by adding other solvents to form binary

solvent including acetone-water (Son et al., 2004;

Quirós et al., 2016), acetone-ethanol (Baptista et al.,

2011), and acetone-DMAc (Tungprapa et al., 2007).

The use of water, ethanol, acetic acid, and DMAc

mixed with acetone has many disadvantages such as

the ratio of water should be smaller, the volatility of

ethanol approaching acetone, and the corrosive

DMAc and acetic acid harm the electrospinning

device. In this study, we were interested in using

acetone and DMSO as binary solvent to dissolve

cellulose acetate. Then cellulose acetate solution was

fabricated into nanofiber by using electrospinning.

2 MATERIALS AND METHODS

2.1 Materials and Devices

Table 1 : Summary of chemical materials used in this

study

Properties

Cellulose

acetate

Acetone DMSO

Form

Density (g/ml) at

25ºC

Solid

1.3

Liquid

0.791

Liquid

1.1

Boiling

Temperature ºC

no data 56 189

Molecular weight

(g/mol)

Mn 30000 by

GPC

58.08 78.13

Chemical materials included cellulose acetate

(CA), acetone and dimethyl sulfoxide (DMSO) were

obtained from Sigma Aldrich.Devices usedinclude

terumo 10 cc srynge and electrospinning series device

from Nanolab instrument (NLi) Company Malaysia.

The summary of chemical is written on Table 1.

2.2 Preparation of Electrospun

Nanofibers

Cellulose acetate (CA) solution was prepared with

concentration 17.5% and 20% (w/v) by dissolvingCA

in acetone:DMSO 2:8 and 3:7 (v:v)under reflux at 40-

C for 2 hours.TheCA solution wasthen transferred

into10 cc terumo srynge. The electrospinning was run

with flowrate 0.10-0.15 ml/h, distance 20 cm and

voltage 8 kV at room temperature.The spun-

nanofibers were collected using a flat collector.

Electrospinning set up is illustrated in

Figure 1.

Figure 1: Electrospinning set up.

2.3 Characterization

2.3.1 Scanning Electron Microscope

The morphology of the fibers was analyzed using a

scanning electron microscope Jeol 6060. To reduce

charging during analysis, the fibers were sputter-

coated with a layer of gold alloy.

2.3.2 Fourier Transform Infrared

The functional group of raw cellulose acetate and

spun-fibers was analyzed using an FTIR

Spectrometer (Nicolet 8700, Thermo Scientific). The

instrument was operated in a transmission-mode with

a resolution of 2 cm

-1

and 100 scans.

3 RESULTS AND DISCUSSION

3.1 Morphology Analysis

The morphology of electrospun nanofibers was

investigated using SEM. Figure 2 and Figure 3 show

the micrographs of CA nanofibers in

acetone:DMSO(2:8 and 3:7). The average diameter of

the spun fibres is written in

Table 2.

IMC-SciMath 2019 - The International MIPAnet Conference on Science and Mathematics (IMC-SciMath)

268

Figure 2: The SEM image of spun fiber: (a)-(b) CA 17.5 % and (c)-(d) CA 20 % (w/v) in acetone:DMSO 2:8 (v:v)

Figure 3: The SEM image of spun fiber: (a)-(b) CA 17.5 % and (c)-(d) CA 20 % (w/v) in acetone:DMSO 3:7 (v:v)

Figure 2 shows that the morphology at CA 20%

was smoother than CA 17.5 %. However, it had bead

fibers. The bead fiber is probably related to the

electrospun jet which get capillary breakup by surface

tension (Fong, Chun and Reneker, 1999).

Additionally, Figure 3 shows that both the

morphology at CA 17,5% had smooth and narrow

morphology almost the same as the morphology of

CA20% cellulose acetate. However, there were some

particles left on the surface of the fiber.

The average diameters data as written in Table 2

explains

that the fiber with CA 20 % had larger

Morphological Investigation of Electrospun Nanoﬁbers Cellulose Acetate-based Membrane

269

Table 2: The average diameter of CA nanofibers.

ratio of

acetone :

DMSO (v/v)

fibers diameters (nm)

17.5 % cellulose

acetate

20 % cellulose

acetate

2:8 301.7 152.2

3:7 165.8 212.1

diameter than CA 17.5 % in acetone:DMSO (3:7).

Higher polymer concentration causes increasing of

fiber diameters as reported in reference (Beachley and

Wen, 2009).In addition, both of fibers in had larger

diameters than the fiber at CA 20 % in

acetone:DMSO (2:8).The larger ratio of volatile

solution also increases diameter of fiber (Tungprapa

et al., 2007). However, the fiber at CA 17.5 % in

acetone DMSO (2:8) had unique attention, whereas

its diameter was larger among all fibers.

3.2 Fourier Transfer Infra-red

Analysis

The FTIR spectra of CA nanofibers and cellulose

acetate powder areshown in Figure 4, and the

wavenumbers of each functional groupare written in

Table 3.

Figure 4 : FTIR spectra of CA and CA nanofibers

The FTIR spectra of CA nanofibers showed broad

peak of O-H stretching at 3487 cm

-1

and medium peak

of CH; CH

or CH

stretching at 2947 cm

-1

(John,

Chen and Kim, 2012). Strong peak which attributes

to C=O functional groupat 1435 cm

-1

and C-O group

at peak 1049 cm

-1

(Ibrahim et al., 2015).

Table 3. The FTIR data of CA and CA nanofiber used in

this study.

Group

Wavenumbers (cm

-1

)

Cellulose

acetate

Cellulose acetate

nanofibe

O-H 3449 3487

C-H 2932 2947

C=O 1751 1751

C=C 1636 1636

1434 1435

C-O 1042 1049

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The C=O group became stronger and slightly

wider after fabrication of cellulose acetate into

nanofiber. It was due to the presence of C=O from

acetone which appeared at 1770-1730 cm

-1

(Hasan,

Zaki and Pasupulety, 2003). The peak at 1049 cm

-1

nanofiber was wider than cellulose acetate. From a

reference reported that the peak S=O of DMSO

appears at 1070 to 1030 cm

-1

(Awadhia and Agrawal,

2007). In this study, DMSO was used in high ratio.

Hence the presence of DMSO affected the peak of IR

spectrum.

4 CONCLUSION

The fabrication of nanofiber from cellulose acetate

dissolved in acetone:DMSO has been done using

electrospinning. The morphology of the nanofiber

dissolved in acetone:DMSO (3:7) is smoother than

acetone:DMSO (2:8). The peak intensity of C=O at

1751 cm

-1

becomes stronger after fabrication of

nanofiber.

ACKNOWLEDGEMENT

The authors acknowledge to Rector of Universitas

Sumatera Utara 2019 for financial support through

TALENTA 2019 with contract number :

4167/UN5.1.R/PPM/2019.

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