superhydrophobic nanocomposites coating using ... · international journal of applied engineering...
TRANSCRIPT
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16032
Superhydrophobic Nanocomposites Coating Using Electrospinning
Technique on Different Materials
Prof. Dr. Balkees Mohammed Diaa
University of Technology, Baghdad, Iraq.
Hassan Talal Jaafar
University of Technology, Baghdad, Iraq.
Abstract
Superhydrophobic coating were fabricated using
electrospinning technique on different substrates (glass,
ceramic and metal) , polymer solutions of (PS/DMF) and
(PMMA/THF) were used in different range of composition for
each solutions, also epoxy and nano TiO2 were used to fabricate
nanocomposites. Contact angle, surface tension, viscosity were
calculated for all specimens. SEM showed the morphology of
the surfaces and show that (20%PS/DMF) has a higher amount
of beads attached with nanofibers and the number of these
beads increased with increasing the viscosity of the polymer
solution (PS/DMF) , (20%PS/DMF) owned a larger contact
angle about (160.739o) for metal substrate and show a
superhydrophobicity for ceramic and glass substrate after
coating with (20%PS/DMF/TiO2). All the results were
discussed.
Keywords: (PS) Polystyrene, (PMMA)
Polymethylmethacrylate, (DMF) N,N-Dimethylformamide ,
(THF) Tetrahydrofuran , (TiO2) Titanium dioxide , (CA)
Contact angle , (SEM) Scanning electron microscope .
INTRODUCTION
In the last few years the interested is grown very much towards
superhydrophobic materials and coatings according to
engineering and nanotechnology requirements to achieve
material with the desired properties which are better than raw
materials. This research focused on studies the
superhydrophobic coating to obtain materials with special
surface properties by testing wettability of coated surfaces
(ceramic, glass and metal substrate) to defining hydrophobicity
and the characteristics of surfaces used, these materials surfaces
were chosen because they are very important in daily people
life use and industrial manufacturing which plays an important
role around this field research. Also tested to SEM (to show the
morphology texture of the surface).
Superhydrophobic coating is refers to static water on the
surface that tested by contact angle and acceded more than 150o
degree. There are different types of superhydrophobic surface
in nature like (lotus leaf, butterfly wings and desert beetle) ,
these examples has superhydrophobic and low adhesions
properties. These unique characteristics showed a great
interested by science and researchers that including (self-
cleaning, anti-corrosion, anti-wetting ..etc.). So this research
specialized on fabricate superhydrophobic coating to get what
almost in nature examples and achieve these unique desired
properties[1].
Electrospinning technique is one of the most efficient and
best method which become common and popular in the last few
years and increased interest by nanotechnology field because
of manufacturing and production of nanofibers polymer with
diameter ranging from (2nm - 5μm). In general, electrospinning
technique contains syringe pump, high voltage source and
collector, the polymer solution put into syringe pump which
pushed in static flow rate and the needle connected to high
voltage source in range (3KV - 30KV)[2].
Electrospinning parameters are the measure of the resulting
material from electrospinning technique that effect on the
properties of the fibers manufactured by this method. There are
many types of electrospinning parameters (Solution
parameters, Instrumental parameters and Ambient or
Environmental parameters)[3].
Solution parameters which include (viscosity and surface
tension). Viscosity considered an important factor that effect
on electrospinning technique , the most important factors
affecting on viscosity is molecular weight and the
concentration of the polymer. Surface tension is also one of
the important factor affecting on electrospinning technique
which effect by the composition of different polymer solution
this will result in changing the surface tension. When there is
high ratio of free solvent molecules, these molecules will mixed
together and will form beads[4].
Instrumental parameters (Applied voltages, Needle-
Collector distance and Feeder rate) in general voltage must be
applied in suitable way that will form the Taylor cone. By
increasing voltage the electrostatic repulsive force on the
polymer solution increased and this result by reducing the
diameter of manufactured fiber[5].
Ambient or environmental parameters (humidity,
temperature and atmosphere), which has important effect on the
form of fiber produced by electrospinning technique[5].
Contact angle, studies the wettability of the surface is very
important in this research which include the perusal of contact
angle test as primary data, and testing the degree of wettability
when the droplet of water touches the coated surface. Contact
angle divided to many sections and every sections include how
much wettability and resistance of the surface to the droplet ,
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16033
specimens in this research will studied by this test to determine
the wettability of the surface that made by electrospinning
technique, and these sections of CA are (figure (1) shows CA
range and its sections) [6] :
Figure 1: Contact Angle Sections and Range.
Materials Used :
Polystyrene (PS) granules from panreac Co. for
didactic (Barcelona - Espan).
Polymethylmethacrylate (PMMA) powder from
MME. , (Dubai - UAE).
Nano titanium dioxide (TiO2) nano particle with
diameter (20nm - 40nm) from micxy reagent
company (China).
N,N-Dimethylformamide (DMF) solution from
sigma-aldrich (SCR). Tetrahydrofuran (THF) solution from (CDH)
Ltd. (New Delhi - India).
Epoxy resin from (sikadu-®52) Co. (USA).
Ethanol (ethyl alcohol) sigma-aldrich (SCR).
Figure 2: Materials Used in The Research.
Experimental Part : The substrate of specimens used (ceramic, glass and metal)
each of them has washed with distilled water and cleaned with
alcohol for 5 min then dried with oven at 35-50o temperature to
obtain a smooth surface without contamination and scratches to
the surface[7]. Figure (3) shows specimens prepared before
coating.
Figure 3: Specimen prepared for (Ceramic, Glass and Metal)
before coating.
For first surface specimen is metal , that coated with (PS/DMF)
solution and (EP) as matrix for (PS/DMF) to make the layer of
(PS/DMF) solution coating good enough to adhesion with
surface of the specimen , also specimen of metal surface is
coated with (PMMA/THF) solution without need EP as matrix
to make adhesion with surface.
The preparation of the (PS/DMF) solution was prepared by
dissolve PS granules in DMF solute in different %wt
composition in range of (5, 10, 15 and 20%wt) of PS granules
and put on a magnetic stirrer for 12 hours to make an
homogenous polymer solution, the percentage of
(20%PS/DMF) was depended in this research because it shows
the larger contact angle over other percent which shows about
(160.739o) degree. EP resin was prepared by ratio of 90:10 (EP
: Hardener) and also diluted with ethanol in percent of 25%wt,
the reason of diluted EP solution that much is to make the
viscosity of the solution good enough to go out the tip of needle
of syringe pump easily[4-8].
The preparation of the (PMMA/THF) solution was prepared by
dissolve PMMA powder in THF solute in different %wt
composition in range of (3, 4 and 5%) of PMMA powder and
put on a magnetic stirrer for 6 hours to make an homogenous
polymer solution, the percentage of (4%PMMA/THF) was
depended in this research because it shows the larger contact
angle over other percent which shows about (151.856o)
degree[9]. Figure (4) shows Metal substrates coated with
(PS/DMF) and (PMMA/THF) solutions.
Figure 4: Metal substrates coated with (PS/DMF) and
(PMMA/THF) solutions.
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16034
For ceramic and glass surface specimens it has coated with
(20%PS/DMF/TiO2) solution and EP as matrix for (PS/DMF),
TiO2 nanoparticle was used in known percentage of %wt that
mixed with (20%PS/DMF) solution to enhance the
hydrophobicity of the ceramic and glass surface in way better
than surfaces only coated with (20%PS/DMF) solution[10].
Figure (5) shows Ceramic and Glass substrates that coated with
(20%PS/DMF/TiO2) solution.
Figure 5: Ceramic and glass substrates coated with
(20%PS/DMF/TiO2) solution.
Set up of electrospinning technique, in general electrospinning
technique contains syringe pump, high voltage source and
collector, in the beginning, this method contains of 3 electrode,
the polymer solution that prepared as explained above put into
syringe pump, the first electrode is connected to the needle of
the syringe pump, the needle diameter is very small and is
connected with high voltage source (8.5KV for PS/DMF),
(6.5KV for PMMA/THF) and (3.5KV for EP), the syringe used
in this research is 3ml size, which pushed in static flow rate.
The second electrode is connected to the board that put the
specimen or substrate on it which called collector and the third
electrode is connected to earth to prevent electrical fault shock.
When an electrical field is granted a boost to the needle of the
syringe pump it produce electro static power that wok on
changing the surface tension of the solution and deform the
shape of spray and make it like conical spiral (Taylor cone) on
the collector board and when the voltage increased the change
in the shape of the droplet increased, when the voltage
stabilized it work on evaporate the solute and fibers produced
by this technique only stay on the substrate or specimen[2-3].
The electrospinning technique can be used for making fibers
with aligned fibrous structure achieved using roller tube
collector (used aligned for metal surface) and non- aligned
fibrous structure achieved using a plate collector (used non-
aligned for ceramic and glass surface). According to the type of
collector used. Also electrospinning apparatus is available in
two different set up, vertical set up and horizontal set up. In this
research the method set up in horizontal method. And the
following figure (6) show electrospinning technique method
preparation and set up as explained previous section.
Figure 6: The Electrospinning Technique Method Preparation
and Set-up .
RESULT AND DISCUSSION
Table (1) shows the result of prepared polymer solutions after
tested to viscosity and surface tension tests. For viscosity show
increasing by increase the amount of polymers percentage that
mixed with solute for both PS and PMMA. By increasing
viscosity of the PS/DMF solution little higher using PS
granules with higher molecular weight or increasing the PS
concentration in the solution, then a mixture of fibers and beads
will be obtained. For (PMMA/THF) the viscosity will be in
appropriate range this will result with smooth micro or
nanofibers.
Surface tension has a direct correlation with viscosity for
(PS/DMF) solutions, and indirect correlation for
(PMMA/THF) solution cause due to the shape of PS granules
as compared to the PMMA powder which make surface tension
more motive to PS than PMMA polymer solution, also the
solute used has effect to surface tension either , figure (7) shows
relation between viscosity and surface tension. The remaining
results are obtained with test as collected receive scan, surface
tension has a direct correlation with actual tension , and for
shear stress it shows increasing with PS and decreasing with
PMMA and this due to the amount of polymers added to the
solute and due to prepared environment. Finally for shear rate
is an constant number and resultant with the viscosity test
device. Figure (8) shows relation between shear stress and
shear flow rate[6].
Table 1: Viscosity, surface tension, actual tension, shear
stress and shear rate results for polymer solutions prepared .
Polymer Solution Viscosity
(m2.sec-1)
Surface
Tension
(N.m-2)
Actual
Tension
(N.m-2)
Shear
Stress
(N.m-
2)
Shear
Rate
(sec-1)
(5%PS/DMF) 5.93 28.47 20.64 11.88 20
(10%PS/DMF) 11.86 30.17 21.87 9.40 40
(15%PS/DMF) 17.79 31.16 22.59 7.34 11
(20%PS/DMF) 23.72 32.53 23.58 7.33 11
(3%PMMA/THF) 9.7 20.7 20.72 2.35 24
(4%PMMA/THF) 15 20.59 20.59 3.6 24
(5%PMMA/THF) 27 20.2 20.14 6.7 24
(5%PS/DMF/TiO2) 20.62 21.03 13.23 15.45 25
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16035
Figure 7: Relation between viscosity and surface tension.
Figure 8: Relation between shear stress and shear flow rate.
Contact angle has tested for all specimens prepared before and
after coating by electrospinning technique, contact angle
measured for specimens (ceramic, glass and metal) before
coating and it show that all surface was hydrophilic. For
ceramic surface shows (0o) CA because of high porosity of the
surface which result as a superhydrophilic material, for glass
surface shows (47.647o) CA and for metal surface shows
(60.493o) which both materials considered as hydrophilic
materials. Figures (9) shows contact angle test for (ceramic,
glass and metal) before coating .
Figure 9 : Contact angle for (ceramic, glass and metal) before
coating A. ceramic surface CA=0O, B. glass surface
CA=47.647o and C. metal surface CA=60.493o
Contact angle has tested for metal specimens after coating by
electrospinning technique, with different percent of (PS/DMF)
solution , and it shows surfaces that coated with (5%PS/DMF)
has contact angle of (121.730o) and for surface coated with
(15%PS/DMF) has contact angle of (121.851o) and both coated
surface mentioned has a hydrophobic properties, while surfaces
coated with (10%PS/DMF) and surface coated with
(20%PS/DMF) has a superhydrophobic properties, in which
(10%PS/DMF) has contact angle of (150.836o) and
(20%PS/DMF) has contact angle of (160.739o). the surface
coated with (20%PS/DMF) has higher contact angle compared
to other coated specimen because of the moderate viscosity and
good surface tension that polymer solution of (20%PS/DMF)
has it. Figures (10) shows contact angle test for metal
specimens coated with different percent of (PS/DMF) solution.
Figure 10: CA. for metal specimens coated with different
percent of (PS/DMF) solution. A. (5%PS/DMF)
CA=121.730O,
B. (10%PS/DMF) CA=150.836O, C.(5%PS/DMF)
CA=121.851O and D. (5%PS/DMF) CA=160.739O.
Contact angle has tested for metal specimens after coating by
electrospinning technique, with different percent of
(PMMA/THF) solution , and it shows surfaces that coated with
(3%PMMA/THF) has contact angle of (100.639o) and for
surface coated with (5%PMMA/THF) has contact angle of
(113.201o) and both coated surface has a hydrophobic
properties, while surfaces coated with (4%PMMA/THF) has a
superhydrophobic properties which has contact angle of
(151.856o) and owns a higher contact angle compared to other
coated specimen because of the moderate applied voltage for
(PMMA/THF) solution. Figures (11) shows contact angle test
for metal specimens coated with different percent of
(PMMA/THF) solution.
Figure 11: CA. for metal surface coated with different
percent of (PMMA/THF) solution. A. (3%PMMA/THF)
CA=100.639O, B. (4%PMMA/THF) CA=151.856O and
C. (5%PMMA/THF) CA=113.201O .
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16036
Contact angle has tested for ceramic and glass specimens after
coating by electrospinning technique with (20%PS/DMF/TiO2)
solution , and it shows contact angle of (154.285o) for glass
coated surface and contact angle of (154.378o) for ceramic
coated surface. This shows in excellent enhancement for
ceramic from (CA=0O) superhydrophilic to superhydrophobic
about (CA=154o). Figures (12) shows contact angle test for
ceramic and glass specimens coated with (20%PS/DMF/TiO2)
solution.
Figure 12: CA. for ceramic and glass coated with
(20%PS/DMF/TiO2) solution. A.Glass surface CA=154.285O
and B. Ceramic surface CA=154.378O.
Specimen of (20%PS/DMF)-Metal , (4%PMMA/THF)-Metal
and (20%PS/DMF/TiO2)-Glass, that owns best contact angle as
compared to other specimens has tested to scanning electron
microscope test (SEM) to see the morphology of the surfaces,
and show that specimen of (20%PS/DMF) have higher amount
of beads and this due to the moderate viscosity or increasing of
PS concentration in the solution, then a mixture of fibers and
beads will be obtained, and due to unbalanced applied voltages
in range of (8.5KV - 9.2KV) also the use of roller tube collector
to obtain alignment nanofibers. As in figure (13), while in
PMMA show beads and defect and this forms because
(PMMA/THF) solution has low viscosity also not need a matrix
because already adhesion with surface so it appears in this way
as in the figure (14), and for (20%PS/DMF/TiO2) shows a great
bonding between nanofibers because of the presence of TiO2
nanoparticles which owns very high surface area that helps to
nanofibers bond to each other with less beads. as in the figure
(15) [11].
Table 2: Shows average contact angle for all specimens.
Polymer Solution Contact Angle
Left (CA_L)
Contact Angle
Right (CA_R)
Contact Angle
Average (CA_AV)
Ceramic - None 0 0 0
Glass - None 47.647 47.647 47.647
Metal - None 60.493 60.493 60.493
(5%PS/DMF) - Metal 120.127 123.333 121.730
(10%PS/DMF) - Metal 146.392 155.281 150.836
(15%PS/DMF) - Metal 117.558 126.145 121.851
(20%PS/DMF) - Metal 158.019 163.459 160.739
(3%PMMA/THF) - Metal 100.639 100.639 100.639
(4%PMMA/THF) - Metal 151.856 151.856 151.856
(5%PMMA/THF) - Metal 111.758 114.645 113.201
(5%PS/DMF/TiO2) -
Ceramic
153.581 155.175 154.378
(5%PS/DMF/TiO2) - Glass 154.285 154.285 154.285
Figure 13: SEM images for (20%PS/DMF) - Metal substrate.
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16037
Figure 14: SEM images for (4%PMMA/THF) - Metal substrate.
Figure 15: SEM images for (20%PS/DMF/TiO2) - Glass substrate.
CONCLUSION
(20%PS/DMF) owns the higher contact angle about
(160.739o) as compared to other (PS/DMF) coated
specimens. (4%PMMA/THF) has the higher contact
angle about (151.856o) as compared to other
(PMMA/THF) coated specimens.
(20%PS/DMF) owns the higher amount of beads due to
the viscosity of (PS/DMF) solution.
(20%PS/DMF) has higher viscosity and surface tension,
(4%PMMA/THF) has moderate viscosity and surface
tension.
Excellent enhancement for (ceramic substrate) after
coating by electrospinning technique with
(20%PS/DMF/TiO2) solution and contact angle changed
from superhydrophilic (0o) to a superhydrophobic
(154.378o) , and the ceramic surface become repels
water instead of absorb water.
REFERENCES
[1] Zhiping Yu, Meimei Wang, Xiaolong Qiu and Jijun
Xiao* " Synthesis and Characterization of Super-Hydrophobic Coating Materials " School of
Materials Science and Engineering, Hebei University
of Science and Technology, 050018 Shijiazhuang,
P.R. China *Corresponding author , 2nd International
Conference on Green Materials and Environmental
Engineering (GMEE 2015).
[2] S. Thenmozhi, N. Dharmaraj, K. Kadirvelu, Hak
Yong Kim " Electrospun nanofibers: New generation materials for advanced applications " ,
Review Article , Pages 36-48 , Materials Science and
Engineering: B, Volume 217,(March 2017).
[3] Haifeng Liu,1 Xili Ding,1 Gang Zhou,1 Ping Li,1
Xing Wei,2 and Yubo Fan1 "Electrospinning of Nanofibers for Tissue Engineering Applications " , Hindawi Publishing Corporation, Journal of
Nanomaterials, Volume 2013, Article ID 495708, 11
pages, (2013).
[4] Siqi Huan 1, Guoxiang Liu 1, Guangping Han 1,*,
Wanli Cheng 1,*, Zongying Fu 1, Qinglin Wu 2 and
Qingwen Wang 1 " Effect of Experimental Parameters on Morphological, Mechanical and Hydrophobic Properties of Electrospun Polystyrene Fibers " , Materials, Volume 8, pages 2718-2734;
(2015).
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 24 (2017) pp. 16032-16038
© Research India Publications. http://www.ripublication.com
16038
[5] NandanaBhardwajSubhas C.Kundu , " Electrospinning: A fascinating fiber fabrication technique" , Biotechnology Advances , Volume 28,
Issue 3, Pages 325-347, May–June (2010).
[6] Yuehua Yuan and T. Randall Lee " Contact Angle and Wetting Properties" , Chapter 1 , springer,
surface science techniques, 663 p, ISBN: 978-3-642-
34242-4, (2013).
[7] Prof. Mohammed S. Prof. Hamza , Alaa Aladdin,
Shatha K. Mohammed, "Fabrication Of TiO2 , V2O5 Thin Film (Super Hydrophobic Surface )By Powder Coating Technique" , Journal of Engineering,
Number 2 Volume 22 February, (2016).
[8] R AZIMIRAD1,∗ and S SAFA2, "Electrospun polystyrene fibers on TiO2 nanostructured film to enhance the hydrophobicity and corrosion resistance of stainless steel substrates" , PRAMANA
journal of physics, Indian Academy of Sciences, Vol.
86, No. 3 , March (2016). [9] GARG, VAISHALIRANI;SINGH,RAVINDRA
NATH, " Hydrophobic Coating of Polymethylmetha-
Crylate (PMMA) on Glass Substrate for Reduced
Bacterial Adhesion " , Journal of Polymer Materials ,
Vol. 32 Issue 4, p503-512. 10p. , Oct-Dec (2015).
[10] T. Sundararajan a b , S. Abirami a b , P. Manohar a b
& S. T. Aruna a, "Preparation and Properties of Water Repellent Polystyrene-TiO2 Coatings" , a
Surface Engineering Division , CSIR-National
Aerospace Laboratories , HAL Airport Road, Post
Bag No. 1779, Bangalore , 560 017 , India b
Department of Ceramic Technology , Anna University
, A. C. Tech Campus, Chennai , 600 025 , India
Published online: 28 May (2012).
[11] Manar Abd Ul- Jabbar Najim, Asst. Prof. Dr. Akram
Raheem Jabur, Asst. Prof. Dr.Emad Saadi Al-
Hassani,
[12] "Preparation and Characterization of an Artificial Tissue Using Polymer Blend by Electrospinning Method" Thesis, University of Technology , Iraq,
(2015).