DOI: 10.3303/CET24114185 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Paper Received: 31 July 2024; Revised: 31 August 2024; Accepted: 08 November 2024 
Please cite this article as: Quiroga-Vergel A., Clavijo-Grimaldo D., Muñoz-González A.M., Ponce-Zapata N., Casadiego-Torrado C., 2024, 
Fabrication and Characterization of PCL/Chitosan and PCL/AgNPs Electrospun Nanofibers for Surface Modification of Cotton Textile, Chemical 
Engineering Transactions, 114, 1105-1110  DOI:10.3303/CET24114185 
 
                                                                                                                                                      

 CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 114, 2024 

A publication of 

 
The Italian Association 

of Chemical Engineering 
Online at www.cetjournal.it 

Guest Editors: Petar S. Varbanov, Min Zeng, Yee Van Fan, Xuechao Wang 
Copyright © 2024, AIDIC Servizi S.r.l. 
ISBN 979-12-81206-12-0; ISSN 2283-9216 

Fabrication and Characterization of PCL/Chitosan and 
PCL/AgNPs Electrospun Nanofibers for Surface Modification 

of Cotton Textile 
Angela Quiroga-Vergela*, Dianney Clavijo-Grimaldo b,c,*, Ana M. Muñoz-Gonzáleza, 
Nubia Ponce-Zapatac, Ciro Casadiego-Torradoc 
a  Centro de Manufactura en Textil y Cuero – SENA, Ave Cra 30 #17-28, Bogotá Colombia. 
b  Facultad de Medicina,Universidad Nacional de Colombia, Carrera 45 # 26 – 85, Bogotá Colombia. 
c  Facultad de Medicina, Grupo INPAC, Fundación Universitaria Sanitas, Calle 170 # 8-41, Bogotá Colombia 
avquirogav@gmail.com; dclavijog@gmail.com 

In the textile industry, particularly for hospital applications, ensuring optimal mechanical properties, balanced 
hydrophilicity/hydrophobicity, and infection resistance is essential to prevent cross-contamination. Nanofibers 
offer a promising solution due to their biocompatibility, high surface-to-volume ratio, porosity, tensile strength, 
and functionalization potential for added properties like antimicrobial. This study electrospinning was used in 
the fabrication of polycaprolactone/chitosan (PCL/CHT) and polycaprolactone/silver nanoparticles (PCL/AgNPs) 
nano/microfibers, applied to commercial cotton fabric. Characterization via scanning electron microscopy (SEM) 
and Fourier transform infrared spectroscopy (FTIR), confirming the presence of nano/microfibers in cotton, while 
tensile tests showed improved fabric strength with binder pre-treatment, maintained after coating. The finished 
textiles exhibited hydrophobic properties, as evidenced by contact angle measurements. Microbiological tests 
with both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria, demonstrated 
that AgNPs effectively inhibited bacterial growth. The antibacterial properties of PCL/CHT were lower than those 
of PCL/AgNPs but like those reported in the literature. These findings highlight the potential of nano/microfibers 
in advanced healthcare textiles. 

1. Introduction 
Antibacterial textiles have been significant throughout human history. Since ancient times, the Egyptians 
functionalized textiles with spices and herbs to wrap mummies, preventing bacteria and fungi from decomposing 
the body. The availability of such textiles allows for a more strategic response to epidemics and pandemics 
(Schneider et al., 2021). The demand for manufacturing antibacterial textiles is on the rise, with various 
polymeric and hybrid nanomaterials emerging as promising candidates for surface functionalization, thus aiding 
in the prevention and control of healthcare-associated infections. This growing market presents an attractive 
opportunity for several developing countries, prompting them to focus on policy development and incentives for 
their textile industries, especially in the realm of technical textiles, to compete with highly industrialized nations 
in textile production. To impart desired properties to these textiles, inorganic or organic antimicrobial agents are 
employed. Among the most extensively researched agents for conferring antimicrobial properties to textiles are 
AgNPs . Alternatively, the manufacturing of natural polymer nanofibers presents itself as a viable option, capable 
of conferring antibacterial activity, typically in fiber diameters smaller than 800 nm (Herrero-Herrero et al., 2021), 
much smaller than those of common textiles, natural and/or synthetic, which generally have fibers with diameters 
ranging from 7 to 20μm or fibers produced by melt-blowing and flash spinning with diameters around 1μm (Pohl, 
2010). The antibacterial properties of nanofibers are important not only for this sector but also for tissue 
engineering, as they enable the manufacturing of dressings or wound healing devices (Li et al., 2021). Various 
techniques have been used for nanofiber manufacturing; however, due to its low cost and reproducibility, 
electrospinning is one of the most widely used today. In this technique, a polymer solution is subjected to high 
voltage. By adjusting variables inherent to the solution used (surface tension, viscosity, solute and solvent 

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characteristics, among others), process variables (voltage, solution flow rate, collector distance), and 
environmental variables (relative humidity and temperature), it is possible to obtain fibers with desired 
characteristics (Clavijo-Grimaldo D. et al., 2022). Leveraging metallic NPs and polymeric nanofibers has been 
of interest to researchers in recent years, as it facilitates the controlled release of the antimicrobial effect of the 
nanofibers, ensuring durability (Avci et al., 2022). Challenges arise when AgNPs are dissolved in polymer 
solutions, such as precipitation or solvent incompatibility with the electrospinning polymer (Villarreal-Gómez et 
al., 2021). One solution is the one-step synthesis of AgNPs, synthesizing the NPs in the polymer solution to 
promote solution homogenization and the electrospinning process (Shi et al., 2011). A more environmentally 
friendly approach includes natural antimicrobial agents such as CHT (Antaby et al., 2021). However, due to the 
low conductivity and high viscosity of CHT solutions, mixing with other polymers more conducive to 
electrospinning, such as PCL, is common practice—a polymer widely used in the biomedical industry due to its 
degradability and biocompatibility. This study conducts a comparative analysis of cotton coatings with PCL/Ag 
and PCL/CHT nanofibers. The objective is to evaluate their impact on mechanical and wettability properties, as 
well as antibacterial effectiveness and to demonstrate the potential of each application to enhance the 
characteristics of textiles used in healthcare. 

2. Materials and Methods 
2.1 Materials 

Polycaprolactone (PCL) (CAS # 134490-19-0 and average Mn = 80.000 g/mol), 100 % acetic acid (AA) (CAS # 
64-19-7), formic acid (FA) (CAS #64-18-6), chitosan 85 % deacetylated (CHT) (CAS # 9012-76-4) and silver 
nitrate (CAS # 7761-88-8) were used. All these chemical agents used were supplied by Sigma-Aldrich. The 
substrates used were commercial 100 % cotton fabric (F) treated with the binder Aprettan NTR ® (B) (N92201) 
supplied by Archroma. 

2.2 Textile pretreatment and solutions preparations 

The F samples were cut into 1 cm diameter circles and immersed in a 50:50 v/v solution of Aprettan NTR® and 
deionized water. They were then dried at 70°C for 8 minutes. To manufacture the nanofibers, a base solution 
of PCL at 8% w/v in a 50:50 v/v mixture of FA and AA was prepared and stored at room temperature for 48 
hours. CHT was dissolved in the PCL solution at concentrations of 5, 10, and 20% w/v (labelled as PCL/5%CHT, 
PCL/10%CHT, and PCL/20%CHT, respectively). PCL/Ag solutions were prepared by adding AgNO3 to the 
solution at concentrations of 0.25, 0.5, and 1% w/v (labelled as PCL/0.25%Ag, PCL/0.5%Ag, and PCL/1%Ag, 
respectively). The resulting solutions were homogenized using ultrasound at a frequency of 50 Hz for 180 
minutes at 21°C. 

2.3 Nanofiber fabrication and cotton fabric functionalization 

The fibers were developed in a vertical electrospinning equipment composed of a high voltage source 
(CZE1000R, Spellman), a dosing pump (NE-300, Micrux), a syringe and a needle (21 gauge). The deposition 
time of the fibers on the F substrates was 60 min over the rotary collector. Applied voltage, needle-collector 
distance and solution flow were the parameters of the electrospinning process that were adjusted until obtaining 
uniform fibers without defects. The parameters of the electrospinning process are found Table 1. 

Table 1: PCL/Chitosan and PCL/Ag electrospinning parameters. 

Sample Flow 
(ml/h) 

Collector 
Distance (cm) 

Voltage 
(kV) 

PCL 0.2 18 10 
PCL/5%CHT 0.2 18 10 
PCL/10%CHT 0.2 15 10 
PCL/20%CHT 0.1 12 12 
PCL/0.25%Ag 0.2 18 10 
PCL/0.5%Ag 0.2 18 10 
PCL/1%Ag 0.2 18 10 

2.4 Physicochemical characterization  

The fiber morphology was studied using Jeol JSM-6010LA (Mitaka, Tokyo). The fiber diameter was analyzed 
using the public domain image analysis software ImageJ software. Mechanical properties were analyzed 
through tensile testing (ASTM D5034:2009). Chemical properties were determined using FTIR (Nicolet iS5) in 

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attenuated total reflectance mode (ATR). Contact angle tests (ASTM D5725-99/2008) were conducted on all 
samples and were calculated using Image J software. 

2.5 Antibacterial Test 

Reference strains of S. Aureus (ATCC 29213) and E. Coli (ATCC 25922) were used, supplied by the 
Microbiology Laboratory of Keralty. Textile  were sterilized using ultraviolet radiation. To assess antimicrobial 
activity, the qualitative method JIS L 1902:2008-Halo was performed. Bacterial strains were placed in contact 
with the textile on nutrient an agar Mueller Hinton (Ad-bio AD-MP16-3) and incubated for 24 h at 37 °C. Bacterial 
viability was evaluated at 48 h of incubation using the LIVE/DEAD™ BacLight™ Bacterial Viability Kit for 
Microscopy (Molecular Probes™). The biofilm formation capacity was determined by detecting 
exopolysaccharides using a 0.02% calcofluor stain. 

3. Results and Discussion 
3.1 Morphological characterization 

Figures 1a and 1b depict that F exhibits a typical woven structure with a flattened morphology and twisted 
ribbon-like fibers, showing a wide diameter distribution with micrometer-sized fibers, consistent with literature 
reports. The manufactured PCL fibers (Figure 1c) have uniform diameter distribution (592.44 ± 138 nm). Figure 
1d illustrates the PCL fibers deposited onto F. 
 

 

Figure 1: Morphology of F, nanofiber and F with nanofibers observed by SEM of (a) initial F 50X, (b) initial F 
500X (c) PCL nanofibers 500X, (d) PCL nanofibers on the F 500X. 

Figures 2 and 3 show independent PCL/CHT and PCL/Ag nanofibers and those deposited on F. In general, 
nanofibers exhibit a smooth, bead-free surface, distributed uniformly. The electrospinning process with the 
incorporation of fabric with a binder in the rotary collector reduced electrostatic charge, resulting in some beads 
appearing on F. When 5 % CHT is added to the PCL, Figures 2a and 2b show smooth nanofibers, but with a 10 
% CHT addition in Figure 2c, beads are observed distributed along the fibers. Regarding the fiber diameter 
distribution, the addition of 5 % CHT results in a diameter of 2300 ± 794 nm. With a 10 % CHT addition, there 
is a substantial decrease in the mean diameter (349 ± 87 nm). 
 

 

Figure 2: Morphology of PCL/CHT nanofibers and PCL/CHT nanofibers on F observed by SEM: (a)PCL/ 5,0% 
CHT (b) PCL/5,0% CHT on F (c)PCL/ 10% CHT (d) PCL/10% CHT on F, (e) PCL/20% CHT, (f) PCL/20% CHT 
on F. 

1107



 

Figure 3: Morphology of PCL/Ag nanofibers and PCL/AG nanofibers on the F observed by SEM of (a) 
PCL/0,25% Ag, (b) PCL/0,25% Ag on F, (c) PCL/0,5% Ag, (d) PCL/0,5% Ag on F (e) PCL/1,0 % Ag, (f) PCL/1,0% 
Ag on F. 
 
The addition of 20 % CHT shows a slight increase in the diameter (532 ± 256 nm), change in trend may be due 
to the change in the electrospinning parameters to achieve smooth fibers. PCL/Ag nanofibers reveal a uniform 
and better-distributed diameter than PCL/CHT fibers, as shown in Figure 3a–f. The obtained diameters decrease 
with the addition of Ag to the fibers, reaching 611 ± 112 nm for 0.25 % Ag, 532 ± 256 nm for 0.5 % Ag, and 453 
± 84 nm for 1.0 % Ag. This behaviour is attributed to the increased electrical conductivity of the polymeric 
solution, resulting in a smaller diameter due to the enhanced charge transport (Avci et al., 2022). The reduction 
in diameter size is a desirable effect as it increases the surface area-to-volume ratio. 

3.2 Mechanical testing evaluation 

The textile without any treatment (F) shows more stiffness and less deformation than textile with binder (F+B) 
and textile with binder and PCL (F+B+PCL). Finding that the addition of the binder does generate significant 
changes in the properties of the textile. On the other hand, when adding the nanofiber coating to the (F+B), 
there no significant change (p<0.05). Additionally, the tensile properties of the textile samples with 
nano/microfibers of PCL/chitosan and PCL/Ag were not significantly different (p<0.05); differing in some tests 
in the breaking point, showing that the coating of nano/microfibers does not generate significant changes in the 
mechanical behavior of the textile with binder. In comparison, the tensile properties of nanofibers with F are 
higher, because of the summation of the mechanical properties of the fabric and the aligned nanofiber of PCL, 
which contributes to enhancing the tensile stretch because of the anisotropy. Finally, there is no difference 
between PCL/CHT and PCL/Ag nanofibers with F, due to the fabric strength, which is so much higher than the 
PCL nanofibers by themselves (Table 2). 

Table 2: Strength, strain and Young’s Modulus of F, F with blinder, and F with blinder and coaching of PCL 
nano/microfibers. 

Sample Tensile Strength 
(MPa)  

Strain (%) Young's Modulus 
(MPa) 

F 103.5 ±3.4 11.1 ±0.3 9.2 ±0.2 
F+B 101.9 ±1.8 13.3 ±0.2 8.4 ±0.2 
F+B+PCL 104.3 ±3.4 13.8 ±1.1 8.4 ±0.4 

3.3 FTIR spectroscopy   

In the spectrum corresponding to initial F (Figure 4a), a peak at 3250 cm⁻¹ (O-H bonds of cellulose) and a peak 
at 1045 cm⁻¹ (O-C bonds) were recognized. On the other hand, upon adding the nano/microfiber coating with 
PCL (spectra b-g), the characteristic peaks of PCL at 2954 and 2870 cm⁻¹ (asymmetric and symmetric CH2 
stretching) and a peak at 1732 cm⁻¹ (C=O bond) are observed. In the case of spectra (b-d), the presence of 
CHT is recognized by the appearance of the band centered around 3441 cm⁻¹ and 3435 cm⁻¹ (O-H and N-H 
bonds). Regarding the spectra (e-f) corresponding to the samples with silver nanoparticles (AgNPs), only the 
base PCL polymer can be identified since it is not possible to recognize the presence of Ag using this technique. 

1108



 
Figure 4: FTIR Spectra (a) initial F, (b) PCL/5% CHT, (c) PCL/10%CHT, (d) PCL/20%CHT, (e) PCL/0,25% Ag, 
(f) PCL/0,5% Ag, (g)PCL/1% Ag. 

3.4 Wettability of fibers   

The sample of F is completely hydrophilic, since, by adding the drop of water, it is immediately impregnated in 
the fabric. On the other hand, when adding the surface modifier with PCL nano/microfibers, is observed a contact 
angle of 112 ±2° ,  indicating that the textile now has hydrophobic properties. This result is due to the hydrophobic 
character of the base polymer of the PCL nanofibers, as it is known in the literature for the molecular composition 
of PCL nanofibers (Tiyek et al., 2019). The contact angles were PCL/5%CHT (115 ±2°), PCL/10%CHT (111 
±2°), PCL/20%CHT (114 ±2°), PCL/0.25%Ag (111 ±3°), PCL/0.5%Ag (115 ±0.4°) and, PCL/1%Ag (74 ±12°). 
Except for the last-mentioned sample, functionalization with PCL/CHT and PCL/Ag shows a significant increase 
in the hydrophobicity of the textile. 

3.5 Antibacterial Test 

In the PCL/CHT samples, bacterial growth was observed before washing. The antibacterial mechanism of CHT 
is based on the interaction between positively charged chitosan molecules and negatively charged entities on 
the bacterial surface. Since this polymer is insoluble in the culture medium, CHT can only act against bacteria 
in the tissue and not those in the medium. After washing, bacterial growth was not observed (Sathiyaseelan et 
al., 2022). In the PCL/Ag samples, there was no evidence of microbial growth on the textile before or after 
washing, showing a better effect (Table 3). Previous studies have shown that PCL fibers possess intrinsic 
antibacterial activity (Clavijo-Grimaldo et al., 2019). Functionalization was not effective in preventing biofilm 
formation, even at higher concentrations (PCL/20%CHT and PCL/1%Ag), as reported in other studies (Vukoje 
et al., 2014). The strains used were highly resistant bacteria, as they were obtained from a reference 
microbiology laboratory at a hospital institution. Therefore, the qualitative observation of the antibacterial 
properties is valid, as it allows for macroscopic identification of population changes due to the effect of the 
material used (Alven et al.,2021). In this study, no quantitative analysis of Ag retention after washing was 
performed, as previous research has shown that PCL nanofibers with AgNPs, fabricated via electrospinning, 
retain a significant number of nanoparticles both within the nanofiber structure and after washing (Korniienko V, 
et al., 2024). This supports the interpretation that the results observed in this study indicate sufficient 
nanoparticle retention to achieve effective antibacterial performance (Permyakova et al., 2023).  

Table 3: Results of proliferation of Staphylococcus aureus or Escherichia coli bacteria on the textile samples. 
(+/-) corresponds to samples where microbial growth/absence of bacterial growth. 

Sample S. aureus E. coli 
 Pre-washing Post-washing  Pre-washing Post-washing 
F + - - + 
PCL - - + - 
PCL/5%CHT +  - + - 
PCL/10%CHT + - + - 
PCL/20%CHT + - + + 
PCL/0.25%Ag - - - - 
PCL/0.5%Ag - - - - 

4. Conclusions 
Nano-microfibers PCL/chitosan and PCL/AgNPs were successfully deposited and adhered to a cotton textile. 
The functionalization increased hydrophobicity, thus providing greater protection against potential contamination 

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with fluids from patients.  This change is important to enhance user biosecurity. The addition of the binder in the 
fabric pre-treatment resulted in increased load resistance in the tensile mechanical test and enhanced 
deformation and resilience of the textile, essential characteristics for specific applications (e.g., hospital 
bedding). As reported in the literature, the antibacterial properties of silver nanoparticles were superior to those 
of chitosan, both before and after washing the textile. Future studies combining both agents are needed, 
expecting a greater antimicrobial effect. 

Acknowledgments 

We thank the Electrospray and Electrospinning Laboratory of the Universidad Nacional de Colombia and 
Laboratory of Centro de Manufactura en Textil y Cuero - SENA, for their support and provision of equipment to 
develop the project and to Unisanitas for the support for the publication of this work 

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	Fabrication and Characterization of PCL/Chitosan and PCL/AgNPs Electrospun Nanofibers for Surface Modification of Cotton Textile