109
Revista Facultad de Ingeniería (Rev. Fac. Ing.) Vol. 26 (45), pp. 109-119. Mayo-Agosto, 2017. Tunja-Boyacá, Colombia.
ISSN Impreso 0121-1129, ISSN Online 2357-5328, DOI: http://doi.org/10.19053/01211129.v26.n45.2017.6420
Sandra Paola Rojas-Lema - Salomé Gabriela Galeas-Hurtado - Víctor Hugo Guerrero-Barragán
pp. 109-119
DOI: http://doi.org/10.19053/01211129.v26.n45.2017.6420
Improvement of silver nanoparticle impregnation on
cotton fabrics using a binder
Mejoramiento de la absorción de nanopartículas de plata en telas de
algodón, utilizando un ligante
Melhoramento da absorção de nanopartículas de prata em tecidos de
algodão, utilizando um ligante
Sandra Paola Rojas-Lema
*
Salomé Gabriela Galeas-Hurtado
**
Víctor Hugo Guerrero-Barragán
***
Abstract
In this work, silver nanoparticles were synthesized by the polyol process, which reduces silver nitrate with ethylene
glycol. The temperature effect and the polyvinylpyrrolidone (PVP) amount were studied. The temperatures
used were 100, 120 and 140 °C. Three ratios of 0.00, 0.25, and 0.50 (% w/w) of PVP/AgNO
3
were established.
Nanoparticles with sizes less than 30 nm were obtained in conditions of 120 °C and 0.5 % w/w of PVP/AgNO
3
.
Posteriorly, nanoparticles in concentrations of 10 and 20 ppm were deposited on cotton fabric by the pad-dry-
cure technique, in order to analyze their bactericidal properties against the Gram positive bacteria Staphylococcus
aureus 25923. The tests showed that cotton fabric with nanoparticles in concentrations of 10 and 20 ppm had good
bactericidal properties, reducing bacterial colonies by over 98 %. Finally, a washing stability study of the fabrics
impregnated with silver nanoparticles was performed, and an acrylic binder was added during the impregnation
process. The results were obtained by bacteriological analyzes.
Keywords: Bactericidal Properties; Binder; Cotton; Silver Nanoparticles.
Resumen
En este trabajo se sintetizaron nanopartículas de plata mediante el proceso de poliol, que reduce el nitrato de
plata con glicol de etileno. Se estudió el efecto de la temperatura y la cantidad de polivinilpirrolidone (PVP). Las
temperaturas utilizadas fueron 100, 120 y 140 °C. Se establecieron tres relaciones: de 0.00; 0.25 y 0.50 (% w/w)
de PVP/AgNO
3.
Las nanopartículas con tamaños menores de 30 nm se obtuvieron en condiciones de 120 °C y 0.5
(% w/w) de PVP/AgNO
3
Las nanopartículas obtenidas en concentraciones de 10 y 20 ppm fueron luego depositadas en telas de algodón,
mediante la técnica “pad-dry-cure” (tela curada y seca), a n de analizar sus propiedades contra la bacteria Gram
positiva Staphylococcus aureus 25923. Las pruebas mostraron que las telas de algodón con una concentración
* Escuela Politécnica Nacional (Quito-Ecuador).
** Escuela Politécnica Nacional (Quito-Ecuador). salome.galeas@epn.edu.ec. ORCID: 0000-0002-6137-663X.
*** Ph.D. Escuela Politécnica Nacional (Quito-Ecuador). victor.guerrero@epn.edu.ec.
Fecha de recepción: 30 de sepembre de 2016
Fecha de aprobación: 18 de marzo de 2017
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Revista Facultad de Ingeniería (Rev. Fac. Ing.) Vol. 26 (45), pp. 109-119. Mayo-Agosto, 2017. Tunja-Boyacá, Colombia.
Improvement of silver nanoparticle impregnation on cotton fabrics using a binder
de 10 y 20 ppm tenían buenas propiedades bactericidas, debido a la reducción de las colonias de bacterias por
encima del 98 %. Finalmente, se llevó a cabo un estudio de estabilidad del lavado de las telas impregnadas con
las nanopartículas de plata, y, además, se utilizó un ligante acrílico durante el proceso de impregnación. Los
resultados se obtuvieron mediante análisis bacteriológicos.
Palabras clave: Algodón; Bactericidas; Ligante; Nanopartículas de plata.
Resumo
Neste trabalho sintetizaram-se nanopartículas de prata mediante o processo de poliol, que reduz o nitrato de
prata com glicol de etileno. Estudou-se o efeito da temperatura e a quantidade de polivinilpirrolidone (PVP). As
temperaturas utilizadas foram 100, 120 e 140 °C. Estabeleceram-se três relações: de 0.00; 0.25 e 0.50 (% w/w)
de PVP/AgNO
3
.
As nanopartículas com tamanhos menores de 30 nm obtiveram-se em condições de 120 °C e 0.5
(% w/w) de PVP/AgNO
3
.
As nanopartículas obtidas em concentrações de 10 e 20 ppm foram logo depositadas em tecidos de algodão,
mediante a técnica “pad-dry-cure” (tecido curado e seco), com o objetivo de analisar suas propriedades contra a
bactéria Gram positiva Staphylococcus aureus 25923. As provas mostraram que os tecidos de algodão com uma
concentração de 10 e 20 ppm tinham boas propriedades bactericidas, devido à redução das colônias de bactérias
por cima dos 98 %. Finalmente, levou-se a cabo um estudo de estabilidade do lavado dos tecidos impregnados
com as nanopartículas de prata, e, além disso, utilizou-se um ligante acrílico durante o processo de impregnação.
Os resultados obtiveram-se mediante análises bacteriológicas.
Palavras chave: Algodão; Bactericidas; Ligante; Nanopartículas de prata.
Cómo citar este artículo:
S. P. Rojas-Lema, S. G. Galeas-Hurtado, and V. H. Guerrero-Barragán, “Improvement of silver nanoparticle
impregnation on cotton fabrics using a binder,” Rev. Fac. Ing., vol. 26 (45), pp. 109-119, May. 2017.
111
Revista Facultad de Ingeniería (Rev. Fac. Ing.) Vol. 26 (45), pp. 109-119. Mayo-Agosto, 2017. Tunja-Boyacá, Colombia.
Sandra Paola Rojas-Lema - Salomé Gabriela Galeas-Hurtado - Víctor Hugo Guerrero-Barragán
I. IntroductIon
Nowadays the nanotechnology development has
experienced a considerable increase. According
to statistics, around 30 % of the products using
nanotechnology contain silver nanoparticles, which
means that their eld of action is important within this
branch of products. Something interesting about silver
nanoparticles is that they are required in low quantities,
so their weight compared to other nanoparticles is
lower [1].
Silver nanoparticles have some applications in
electronics and chemistry, due to their electrical and
thermal conductivity, chemical stability, and catalytic
activity among others, which has made possible their
use in paints, microelectronics, and medical imaging.
In the environmental eld, these nanoparticles have
been of great help for water antibacterial treatment.
Additionally, in medicine these nanoparticles have
had a great repercussion because they can be used to
obtain coating materials for medical devices, such as
catheters or bandages [2, 3].
On the other hand, silver nanoparticles are widely used
in the textile area, where their incorporation provide
wrinkle resistance and antibacterial properties, among
others [4]. Referring specically to its bactericidal
properties, there are several clothing product lines
using this new technology, such as sportswear
with water repellency, washing durability, better
thermal performance, and odor removal properties.
Additionally, these tissues are used in medical clothing
such as gowns, gloves, masks, etc., in order to avoid
disease transmissions and premature wear of tissues
[3].
Interest in the application of nanoparticles in the textile
eld has grown because certain microorganisms
have increased their resistance to some antibiotics.
Therefore, new control alternatives are studied,
because textiles are in direct contact with human
skin, making them more prone to diseases contagion
[5]. This technology has been applied mainly in
cotton fabrics, due to their susceptibility to become
nests for microorganism reproduction, since they are
composed of natural bers and absorb more moisture.
Additionally, the technology has been applied on
synthetic fabrics such as polyester and nylon, which
have lower moisture absorption, static reduction, and
improved water repellency compared to cotton [6]. As
mentioned before, the advantage of using nanoparticles
is that they are only required in low quantities, which
can be corroborated with the studies of Lee and Jeong
[7], who indicated that with concentrations of 10, 20
and 30 ppm of silver nanoparticles impregnated in
cotton fabric, the number of bacterial colonies could
be reduced by 99.99 %.
Studying the addition of nanoparticles to textiles
requires good adhesion, so that the properties acquired
have the desired effect. Therefore, the use of binding
agents is highly important because they can be a link
between the textile and the nanoparticles, avoiding
the loss of nanoparticles over time due to the use or
washing. Among the available binders, there are those
based on acrylates, butadiene, and vinyl acetate. The
nal requirements, the applications, as well as the cost
should be considered in order to choose the type of
binder [8].
Nowadays, there are studies on related topics such as
those of El-Rae et al. [9], who impregnated silver
nanoparticles in cotton fabric at a concentration
of 50 ppm, with and without 1 % of acrylic binder.
According to their results (obtained by atomic
absorption spectrophotometry), the silver content
was 63.20 and 72.15 mg/kg respectively, indicating
that the binder achieves greater adhesion of silver
nanoparticles [9]. Another example is the study
of Gupta et al. [10], who, in order to determine the
self-cleaning activity achieved by the fabrics, used
nanoparticles of titanium dioxide and zinc oxide in
cotton fabrics with percentages between 1 and 10 of
acrylic binder, obtaining better results with the lowest
percentage of binding agent.
This study aims at obtaining a cotton fabric with
bactericidal properties. To achieve this, silver
nanoparticles were synthetized and eventually added to
the tissues; then, they were subjected to bacteriological
analysis, with exposure to the Gram positive bacteria
Staphylococcus aureus 25923. Subsequently, the
fabrics solidity in respect to washing was studied to
verify the adhesion of the nanoparticles to the fabrics
using a binding agent, for which a new bacteriological
analysis was performed.
I. IntroductIon
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Revista Facultad de Ingeniería (Rev. Fac. Ing.) Vol. 26 (45), pp. 109-119. Mayo-Agosto, 2017. Tunja-Boyacá, Colombia.
Improvement of silver nanoparticle impregnation on cotton fabrics using a binder
II. Methodology
A. Synthesis
Silver nanoparticles were synthetized by the
polyol method, in which silver ions were reduced.
The reagents used were silver nitrate (AgNO
3
),
polyvinylpyrrolidone (PVP) as stabilizing agent, and
ethylene glycol (C
2
H
6
O
2
) as a solvent and reductant.
PVP and ethylene glycol solutions were heated to 100,
120 and 140 ° C, considering 0, 0.25 and 0.50 (% w/w)
of PVP/AgNO
3
. When the solution reached the desired
temperature, a silver nitrate and ethylene glycol
solution was added and allowed to react. The obtained
solution was washed with acetone by centrifugation to
achieve the nanoparticles precipitation.
B. Characterization of nanoparticles
A Brookhaven 90 plus dynamic light scattering
equipment (DLS) was used to determine the size
and dispersion of the nanoparticles. In addition, a
FEI Tecnai G2 Spirit Twin transmission electron
microscope (TEM) was used to establish the
nanoparticles morphology.
C. Impregnation of nanoparticles in cotton fabrics
The pad-dry-cure method was used to impregnate the
nanoparticles in cotton fabrics. Circular cotton samples
of 4.8 cm diameter were treated with 10 and 20 ppm
silver nanoparticle solution. The impregnation was
carried out in two cases: In the rst case, the fabrics
were dipped separately into each of the mentioned
solutions for a period of 10 minutes, after which the
excess solution was removed from the fabric samples
and subjected to a drying process at 90 °C for 10
minutes; nally, the samples were cured at 120 °C
for 3 minutes. For the second impregnation case, an
acrylic binder (Sennelier) consisting of a pure acrylic
resin was used; this binder was added to the silver
nanoparticle solution before dipping the fabric into
1, 3 and 5 % w/w of binding agent. The subsequent
impregnation conditions were the same as those in the
rst case.
D. Bacteriological analysis of impregnated fabrics
The AATCC Test Method: We used the 100-2004
standard as a quantitative analysis of the number of
formed microorganisms. We used the Gram positive
bacteria Staphylococcus aureus 25923, in order to
determine whether the fabric samples impregnated
with the two different concentrations of silver
nanoparticles had acquired bactericidal capacity.
Bacterial colonies reduction was calculated by
equation (1):
(1)
Where A is the number of colonies in a sample with no
treatment, and B is the number of colonies in a sample
with treatment.
E. Washing of cotton fabrics
The fabric samples impregnated with silver
nanoparticles were subjected to 10 washing cycles,
in a standard laboratory equipment Launder-Ometer.
The fabrics were placed into stainless steel containers
with 150 ml of a 0.15 % w/w solution of water with
detergent. The AATCC Test Method 61-2009 was
used at a temperature of 49 (± 2) ° C.
III. results and dIscussIon
We performed a total of nine tests with the conditions
of temperature and weight ratio of PVP/AgNO
3
stated
in section 2. The nanoparticles effective diameter was
determined by dynamic light scattering as shown in
Table 1. The best result (smallest size) is shown in
gure 1. A small particle size is important because
it can facilitate its integration into the cotton fabric.
On the other hand, the smaller the particles are,
the greater is the covered surface area, and their
bactericidal capacity, since they will have greater
interaction with the microorganisms [11]. In addition,
according to the studies carried out by Lee and Jeong
[7], when the particle size is small, there is a lower
risk of skin irritation in the case of direct contact of
nanoparticles with human tissues. Therefore, we used
the polyol method, since it allows better control of the
nanoparticles size and shape [12].
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Revista Facultad de Ingeniería (Rev. Fac. Ing.) Vol. 26 (45), pp. 109-119. Mayo-Agosto, 2017. Tunja-Boyacá, Colombia.
Sandra Paola Rojas-Lema - Salomé Gabriela Galeas-Hurtado - Víctor Hugo Guerrero-Barragán
table 1
EffEctivE diamEtEr of silvEr nanoparticlEs
PVP/AgNO
3
weight ratio Temperature (°C) Effective diameter (nm)
0.00 100 200.5
0.00 120 147.1
0.00 140 152.9
0.25 100 111.3
0.25 120 77.4
0.25 140 98.8
0.50 100 67.2
0.50 120 39.5
0.50 140 75.5
Both temperature and amount of PVP inuenced the
nanoparticle size; the higher the amount of PVP, the
lower the size of the nanoparticle. These results agree
with those obtained by Rosas and Ruiz [13], who
indicated that a greater amount of stabilizing agent
(PVP) allows a decrement in the particle size. This
phenomenon occurs because the PVP coating of the
nanoparticles prevents agglomeration.
FIg. 1. Effective diameter size of 39.5 nm. Sample prepared at 120 °C and 0.5 (% w/w) of PVP/AgNO
3
.
Figure 1 shows a bimodal intensity curve versus
the particle diameter. This is due to the solution
polydispersity, since the capacity of the nanoparticles
to disperse the incident light depends on their diameter.
For this reason, those of larger size will present a
greater intensity and vice versa [14].
Another important factor is the nanoparticle stability,
which depends on several factors, including the
solution temperature and the amount of reducing
agent used. This is due to the action of the Van Der
Waals and Coulomb forces that act as attraction
and repulsion, respectively, and even steric forces
corresponding to the action of the stabilizing agent,
as they produce a barrier preventing the nanoparticles