Studying the Structural, Electrical Properties and Antibacterial Applications of PMMA-PEO/SiO2 Nanocomposites

INTRODUCTION
Nanocomposites demonstrate remarkable properties owing to a distinctive amalgamation of constituents. The swift demand for elastomers and engineered plastics is noteworthy [1]. Their applications span several industries, including packaging and other purposes [2,3]. Nanotechnology involves the creation and utilisation of nanocomposites, offering innovative methods and commercial prospects across multiple industries, such as automotive, aerospace, superconductors, electronics, and both physical and chemical fields, with dimensions spanning from individual molecules or atoms to submicron scales [4-7]. Nanotechnology is often seen as the next industrial revolution. Nanocomposite polymers, including organic polymers and nanoscale inorganic nanoparticles, are novel materials that have attracted significant interest in recent years [8,9]. These composite materials differ from pure polymers in both chemical and physical properties [10,11]. This might be very substantial and advantageous for several candidates across multiple applications [12,13]. The incorporation of nanoparticles into a polymer matrix may substantially improve the optical characteristics of the material with modest amounts of nanoparticles. One advantage of nanoparticles as polymer additions, compared to conventional additives, is their minimal loading needs, attributable to their substantial influence on physical characteristics [10]. The optical properties of polymers are essential for investigating electronic transitions and their prospective use as optical filters. Data on the electrical structures of amorphous and crystalline semiconductors is often acquired by analysing optical characteristics over extensive frequency ranges [4]. Polymethyl methacrylate (PMMA) is a linear thermoplastic polymer. The melting point is 160 °C, while the glass transition temperature is 115°C [14]. PMMA exhibits superiority One semicrystalline polymer with potential bio-electrochemical usage is poly(ethylene oxide) (PEO) [15-18]. At temperatures beyond its melting point, PEO’s optical and electromagnetic properties 
are insufficient, which is its only drawback in practical applications. In order to improve its features [19,20]. In order to achieve thermal stability beyond the nanocomposite’s melting point, PEO nanocomposite structures, which include nanoparticles, have strong interactions with surface functional groups [21]. Incorporating a variety of nanocomposites put into PEO material may improve its qualities and increase its applicability in many fields [22]. The number 23. Because of its unique chemical properties, PEO has found widespread usage in a variety of contexts [23,24]. Silica (SiO₂) is also known as silicon dioxide. Among the many interesting properties of silicon dioxide nanoparticles (SiO2) are their low toxicity, biocompatibility, physiologically degradability, cheap cost, and thermal and chemical stability. They may also be functionalised with a wide range of agents and plastics. Glass, steel, chemical strands, plastic, batteries, paints, makeup, and other environmental protection Businesses in may also find extensive application for nano-silica. The strength, hardness, wear, and age resistance of polymers enhanced by silica nanoparticles are much greater [25].

MATERIALS AND METHODS
The casting procedure was used to create the (PMMA-PEO/ SiO2) nanocomposite.  At room temperature, 1 gramme of (PMMA-PEO) and SiO2 were dissolved in 50 millilitres of chloroform alcohol using a magnetic stirrer to thoroughly mix and dissolve the material.  The weight ratios of SiO2 nanoparticles added to PMMA-PEO were(1.4,2.8,4.2, and 5.6%.  Using a 10-centimeter-diameter Petri dish as a mould, pouring the liquid in, waiting for it to dry, and then carefully removing it for testing is the casting procedure.

RESULTS AND DISCUSSION
FTIR spectra of (PMMA/PEO/SiO2) nanocomposites
Fig. 1 depicts the various peaks in FT-IR spectra of (PMMA-PEO/SiO₂) nanocomposites at distinct concentrations (pure, 1.4, 2.8, 4.2, 5.6wt %) of (SiO₂), which are situated within the range of (4000 - 500) cm⁻¹. Fig. 1-a illustrates the FTIR spectrum of (PMMA-PEO/SiO₂), which features a prominent peak near (1723.83) cm⁻¹, corresponding to the carbonyl stretching (C=O), primarily indicating the interaction between PMMA and PEO. The bending vibration of (CH2) is seen at 1448.50 cm⁻¹, whereas the stretching vibration of the (C-O) group occurs at 1099.68 cm⁻¹. Fig. 1-b also exhibits several peaks, specifically at 1485.87 cm⁻¹ and 1099.33 cm⁻¹, which correspond to the (CH₂) and (C-O) bonds, respectively. The signal detected at 1724.50 cm⁻¹ pertains to the carbonyl (C=O) functional group. The peak at 1099.33 cm⁻¹ is the (C-O) The carbonyl group being stretched of the pmma compound. This (C-H) bending occurs at a peak of 961.34 cm⁻¹, outside the absorption plane of the rings. In Fig. 1-C, peaks are discerned at 1724.25 cm⁻¹ and 1099.37 cm⁻¹. The peak at 1724.25 cm⁻¹ relates to the stretching vibration of the PMMA’s carbonyl group polymer. In comparison, the peak at 1099.37 cm⁻¹ is linked to the stretching vibration of the C-O bond, accompanied by an additional absorption peak at 960.62 cm⁻¹ connected with the bending of the rings. The FT-IR is presented [26]. Fig. 1-d demonstrates that the peak at 1724.83 cm⁻¹is attributable to (C=O). Distinct peaks of (C-H) bending and (C-O) stretching are observed at 961.41 cm⁻¹ and 1100.41 cm⁻¹, respectively. Fig. 1-e depicts the peaks at 1725.30 cm⁻¹ associated with the (C=O) group. While at the peak 1100.36 cm⁻¹, (C-O) stretching. The FT-IR measurements demonstrate that no chemical reaction occurs; physical bonding or contacts are evident [27,28].

Field-emission scanning electron microscope (FESEM)
The arrangement of silicon oxide (SiO2 nanoparticles) within the polymer is examined through field-emission scanning electron microscopy (FESEM), and the influence of these particles on the nanocomposites is assessed.  Fig. 2 present FESEM images of films derived from PMMA-PEO/ SiO2 nanocomposites, exhibiting different concentrations of Si and SiO2 nanoparticles The.incorporation of silicon oxide (SiO2 nanoparticles) within the polymer matrix was analysed using field-emission scanning electron microscopy (FESEM), and the effects of these particles on the properties of the nanocomposites were assessed.  Fig. 2 presents FESEM images of films derived from PMMA-PEO/ SiO2 nanocomposites, showcasing varying concentrations of SiO2 nanoparticles.  Fig. 2-a demonstrates the cohesiveness and homogeneity of the polymer, showing that the addition of SiO2 nanoparticles to the PMMA-PEO polymer modifies the surface structure of the system, as evidenced by images B, C, D, and E in the figure. The average grain sizes derived from the FESEM images were 61.6 nm, 39.6 nm, 33.9 nm, and 54.51 nm for SiO2 nanoparticles at concentrations of 1.4%, 2.8%, 4.2%, and 5.6%, respectively.  FESEM images demonstrate a reduction in average grain size of 2.8% and 4.2% upon the incorporation of silicon dioxide nanoparticles, succeeded by an increase of 5.6%.  This is consistent with the researchers’ findings [29].

The Results of A.C. Electrical Properties
Dielectric constant (ɛ›) and dielectric loss (ɛ››) of (PMMA-PEO/SiO2) Nanocomposites
Figs. 3 and 4 demonstrate that the dielectric constant and dielectric loss fluctuate with frequency for nanocomposites consisting of (PMMA-PEO/SiO2).  The images illustrate that Maxwell-Wagner polarization results in elevated dielectric constants and losses at low frequencies.  Nevertheless, when the frequency increases, these values decrease across all samples.  The contacts between insulators and conductors produce this polarization. The buildup of dipoles or space charges at interfaces results in polarization on those surfaces.  As the frequency of the electric field that is being used diminishes, the reaction time of the space charges increases.  Nevertheless, the polarization effect diminishes when the electric field fluctuates rapidly within the higher frequency spectrum. The loss of dielectric and the dielectric constant diminish as the frequency increases.  This behaviour supports the researchers’ conclusions [30].
Figs. 5 and 6 illustrate the correlation between the dielectric constant and dielectric loss as a function of the density of (PMM-PEO/ SiO2) nanoparticles at room temperature and (100) Hz.  We determine the dielectric constant and dielectric loss of PMM-PEO/ SiO2 using the formulae (ɛ’ = Cp/Co) and (ɛ’’ = ɛ’D).  Darker and smaller regions signify a decreased concentration of (PMM-PEO/ SiO2) nanoparticles.  These patches develop at a concentration comparable to that of PMM-PEO/ SiO2 nanoparticles.  The network will have overlapping routes that interconnect some regions with many nanoparticles, facilitating the movement of charge carriers.  With a rise in the density of (PMM-PEO/ SiO2) nanoparticles, both the dielectric constant and dielectric loss elevate, ascribed to the augmented quantity of free Carriers of charge and polarization charges.  This discovery aligns with [31].

Electrical conductivity of (PMMA-PEO/SiO2) nanocomposites 
The A.C. conductivity of nanocomposites is calculated by using the equation (σA.C = ⱳ Ɛo Ɛ’’ )   . The variation in alternating current (AC) electrical conductivity for (PMMA-PEO/ SiO2) nanocomposites is shown in Fig. 7. This variation is demonstrated as a function of the frequency of the electric field at room temperature. As can be seen in the illustration, the electrical conductivity of alternating current increases with frequency. This is because space charge polarization causes the conductivity to increase. In order to contribute to this phenomenon, low-frequency space charge polarization and the stimulation of charge carriers to higher states in the conduction band are both elements that are involved [32]. Electronic polarization and the mobility of charge carriers are the two factors that contribute to the improvement of conductivity at higher frequencies. The velocity of the primary chain and the flow of ions are the two factors that have an effect on the conducting capacity of alternating current. At a frequency of 100 hertz, the influence of the concentration of SiO2 nanoparticles on the conductivity of electricity of the PEO-PMMA mix is shown in Fig. 8. Because of the concentration of SiO2 nanoparticles, there is an increase in the charge carrier density inside the polymer medium, which leads to an increase in the alternating current electrical conductivity.[33]. 
Application of (PMMA-PEO/SiO2) nanocomposites for antibacterial efficacy
A visual representation of the inhibitory zones for Staphylococcus and Klebsiella pneumoniae may be found, as shown in Fig. 9, The antibacterial effectiveness of nanocomposites composed of polymethyl methacrylate (PMMA) and polyethylene oxide (SiO2) was assessed for both gram-positive bacteria (Staphylococcus aureus) and gram-negative microbes (Klebsiella pneumoniae). Based on the findings, it can be seen that the diameter of the inhibitory zone augmentations as the density of SiO2 Nanoparticles increases [34].  It is increased from 0 mm to 23 mm for the Klebsiella pneumoniae and from 0  mm to 22 mm for the S. aureus for the PMMA - PEO / SiO2 It is possible that the antimicrobial agent effectiveness of the nanocomposites might be attributed to the production of reactive oxygen species (ROS) by a variety of nanoparticle molecules.  There is a possibility that the oxidative stress brought about by reactive oxygen species (ROS) is the fundamental mechanism that is responsible for the antibacterial activity of nanocomposites that are formed by nanoparticles. There are a number of radicals that are included in reactive oxygen species (ROS). These radicals include There are four types of radicals: superoxide (O₂), hydroxyl (-OH), hydrogen peroxide (H₂O₂), and singlet oxygen (-O₂).
In bacteria, it has the potential to cause damage to both DNA and proteins. Possibly, the generation of reactive oxygen species by silicon dioxide was responsible for the suppression of the most hazardous microbes. On the other hand, the nanoparticles that are included inside the nanocomposites have negative charges, which causes an electromagnetic attraction to exist between them and the microbes contained within them. After the attraction has been formed, the microorganisms will go through the process of oxidation and will eventually die [35]. With regard to the nanocomposites composed of PMMA-PEO/SiO2, the width of the inhibitory zone is shown in Table 1. 

 
CONCLUSION
FTIR analysis revealed no chemical interaction between the SiO2 nanoparticles and the polymers used in the PMMA-PEO/ SiO2 nanocomposites. FESEM examination revealed the homogeneity of the silicon dioxide and PMMA-PEO nanocomposites, and that the average grain size decreased with increasing SiO2 content. The study revealed a decrease in the dielectric constant ɛ’ of the samples with increasing applied electric field strength, a trend consistent with the observed dielectric loss patterns ɛ’’. Increasing frequency enhanced the alternating current electrical conductivity of the PMMA-PEO/ SiO2 nanocomposites. The dielectric loss and dielectric constant values increased at all concentration combinations with increasing silicon dioxide content. The antibacterial activity of the PMMA-PEO/ SiO2 nanocomposites indicated that the zone of inhibition against Staphylococcus aureus and Klebsiella pneumoniae increased with increasing amounts of silicon dioxide nanoparticles.  This demonstrates the potential of nanomaterials in medical applications, such as killing and inhibiting bacteria, and electrical and industrial applications.

CONFLICT OF INTEREST
The authors declare that there is no conflict of interests regarding the publication of this manuscript.