**3. Food and personal care industry**

AgNPs in the food industry, [33] reported for antibacterial and conservationfree action, are commonly used. Most viruses and bacteria are harmless for humans but lethal, so they are used for sanitising food and drink every day, and they are immune to drug infections. Nanosilver fresh food bag is one of the bags that are ready for sale on the market. Because of its anti-fungicidal and anti-bactericidal activity, AgNPs are commonly used in everyday goods such as soap, fruit, plastics and pastes. Nano-based smart and active foods provide many advantages over standard packaging approaches to increase mechanical efficiency, barrier properties and antimicrobial films for nano-sensitive pathogens identification and alert customers to food protection [34]. "Active content" nanocomposites for packaging and material food packaging may also be strengthened with coating. Many researchers are aware of and important to organic compounds' antimicrobial characteristics, such as essential oils, organic acids and bacteriocins as an antimicrobial packaging, polymeric matrices. However, these compounds cannot be used for different processing phases in food susceptible to physical environments that require high temperature and pressure. Inorganic nanoparticles' use makes it possible to obtain good antibacterial activity in low concentrations and become more soluble under intense conditions. It is also noteworthy that these nanoparticles are recently used in antimicrobial food packaging [35]. Control of food quality has become a global, very common problem. AgNPs have unique physicochemical properties that can be used to produce, package and store food. AgNPs could additionally develop into detectors that are capable of recognising or responding to changes in environmental conditions, such as molecular contaminants, microbial quality organisms, gases. Another popular method used is electrochemical detection based on nanomaterial sensors in the food sector [36].

AgNPs had been added into skincare (**Figure 3**), body wash, cosmetics, deodorants, and others with the advancement of personal care technology. This had urbanised the use as antibacterial agents of AgNPs. AgNPs are added as an antiseptic into personal care products for skin problems. Interestingly, AgNPs also have been incorporated in make-up remover cloth, textiles, gloves, bath towels and cleaning fabrics. Such an application's relevance is silver's natural ability to remove

**Figure 3.** *AgNPs image with 20 nm diameter under a transmission electron microscope (TEM) in a skincare product.*

bacteria as a major cause amount of infections in the skin. Silver ions also prevent their persistence and eliminate them very easily on the microfiber fabric. AgNPs are very helpful in maintaining the optimal balance of the skin condition as they preserve a stable pH by preventing usage of other chemicals in a wide range of items. Regardless of gender or age, AgNPs have shown excellent results, including people with the most sensitive skin. It was tested that consumer goods that contain small quantities of AgNPs do not have major effects on health.

## **4. Nanophysics applications**

Nanophysics is an area which studies more the artificial assembly and fabrication of nanostructures as well as research of their external size effects. To identify and measure them, Nanophysics develops different devices and instruments. A range of manufacturing techniques, including e-beam lithography, focused-ionbeam milling, nano-manipulation, and self-assembly, are used to create novel materials, structures and devices [37] Novel nanostructured architectures have been developed in nanomaterial science. In addition, functional nanomaterials and intelligent nanocomponents with special properties have also been manufactured with the integration of AgNPs [38].

#### **4.1 Fabrication of antennas**

There are two ways of silver-based antenna fabrication. The first fabrication is with nano-metallic silver, and the other one contains micrometre-sized grains. These two samples are prepared through a thick-film fabrication procedure. The metal powder is used as a material for preparation; the metal oxide is used as an inorganic metal binder and an organic vehicle that evaporates through the initial stages. These samples are usually characterised for electrical performances. It was found that in the lower frequency range, of both samples had similar behaviour with a loss in an electrical parameter and linear increase in the frequency range (from 0.1 dB/mm/GHz up to 80 GHz), but beyond 80 GHz frequency, the prepared AgNPs had a lower electrical loss, for the entire frequency range. The lower loss from the AgNPs and the broad range in loss per wavelength does not rely on the frequency. Hence, it has been summarised that the AgNPs fabricated conductors showed a very less electrical loss with higher frequency range which in turn assigned to the roughness present in the lower side of the nanoparticles because of better packing may allow opportunities for low-temperature fabrication of antennas and sub-THz metamaterials with the improved performance [39].

#### **4.2 In electronically conductive adhesives**

AgNPs can be utilised as a silver paste in the electrodes due to their high conducting nature. It is also used as conductive fillers in electronically conductive adhesives (ECAs). A few of the research groups have prepared the AgNPs by reducing the silver nitrate with ethanol in polyvinylpyrrolidone (PVP) [40]. Different reaction conditions have been tuned like PVP concentration, reaction time, and reaction temperature. In this method, PVP prevents aggregation; and also increases the nucleation rate spontaneously and simultaneously decreases the size of the silver nanoparticles. Ethanol is used as the reducing agent to adjust the viscosity of the ECAs. The produced AgNPs with the chemical reduction method showed very fine dispersion and narrow size distribution. Ethanol is also used for the re-dispersing of AgNPs. The absorption peak was recorded at 410 nm, which is an indicator of the

**225**

**Figure 4.**

*Silver Nanoparticles in Various New Applications DOI: http://dx.doi.org/10.5772/intechopen.96105*

superhydrophobic AgNR arrays (In **Figure 4**).

**4.3 Ink-jet printing**

and the reaction time.

quantum size effect of the AgNPs, which is occurring in the absorption property of AgNPs. It is also summarised that the size of the AgNP has been decreased with an increase in the concentration of silver nitrate, the increase in reaction temperature,

Researchers have synthesised AgNPs, silver nanorods, and epoxy resins containing high-performance electrically conductive adhesives (ECAs) using a novel preparation method. The synthesised nanoparticles and nanorods were dispersed well, with the absence of agglomeration in the matrix. The volume electrical resistivity tests determine the volume electrical resistivity of the ECA was close correlates with the various sintering temperatures and time and time, and the ECA could achieve the volume electrical resistivity of (3–4) × 9 10–5 Ω after sintering at 160 °C for 20 min. Hence, they found that the synthesised and prepared ECA to tend to achieve low-temperature sintering and showed excellent electrical, thermal, and mechanical properties [40]. **Nano metal particles such as Ag, Cu, Zn, and Au are particularly useful for electrical circuitry development because nano-sized metal particles can be shielded from inks and can also be used to boost electrical conductivity. Uniformly formed AgNPs are capable of exhibiting improved electrical conductivity, which makes electronic stuff beneficial. Films with sufficiently smooth and continuous surface morphology may be manufactured by adding AgNPs at a level of 0.05 g/100 g (0.05 per cent) in the CS-GL matrix. It has also demonstrated** 

**desirable mechanical strength for industrial packaging. CS-GL-AgNPs at 0.1 g/100 g (0.1 per cent) amount of film proved to be a promising protective packaging material that could increase the shelf life of red grapes by 14 days.** A study [41] reported a simple method to manufacture surface improved fluorescence spectroscopy (SEFS) substrates based on highly sensitive superhydrophobic Ag nanorods (AgNR) arrays using the glancing angle deposition method at 133 K substrate temperature and resultant coating of molecules of heptadecafluoro-1-decanethiol (HDFT). SEFS substrates display more than 3 times greater fluorescence signal amplification than traditional AgNR films in the HDFT coated

Ink-jet technology for electronic circuit manufacturing at very low costs has been used, and additional applications in this desirable technology have been noted. It is very interesting to create powerful inks for the versatile display of electronic devices using ink-jet technology. Researchers have prepared the AgNPs through chemical reduction from the silver nitrate using triethylamine to reduce and protect agents. The nanoparticles have been sintered through washing it with

*SEM image of silver nanorods grown on the Si substrate at (a) 313 K and (b) 133 K [41].*

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

small quantities of AgNPs do not have major effects on health.

**4. Nanophysics applications**

with the integration of AgNPs [38].

**4.1 Fabrication of antennas**

bacteria as a major cause amount of infections in the skin. Silver ions also prevent their persistence and eliminate them very easily on the microfiber fabric. AgNPs are very helpful in maintaining the optimal balance of the skin condition as they preserve a stable pH by preventing usage of other chemicals in a wide range of items. Regardless of gender or age, AgNPs have shown excellent results, including people with the most sensitive skin. It was tested that consumer goods that contain

Nanophysics is an area which studies more the artificial assembly and fabrication of nanostructures as well as research of their external size effects. To identify and measure them, Nanophysics develops different devices and instruments. A range of manufacturing techniques, including e-beam lithography, focused-ionbeam milling, nano-manipulation, and self-assembly, are used to create novel materials, structures and devices [37] Novel nanostructured architectures have been developed in nanomaterial science. In addition, functional nanomaterials and intelligent nanocomponents with special properties have also been manufactured

There are two ways of silver-based antenna fabrication. The first fabrication is with nano-metallic silver, and the other one contains micrometre-sized grains. These two samples are prepared through a thick-film fabrication procedure. The metal powder is used as a material for preparation; the metal oxide is used as an inorganic metal binder and an organic vehicle that evaporates through the initial stages. These samples are usually characterised for electrical performances. It was found that in the lower frequency range, of both samples had similar behaviour with a loss in an electrical parameter and linear increase in the frequency range (from 0.1 dB/mm/GHz up to 80 GHz), but beyond 80 GHz frequency, the prepared AgNPs had a lower electrical loss, for the entire frequency range. The lower loss from the AgNPs and the broad range in loss per wavelength does not rely on the frequency. Hence, it has been summarised that the AgNPs fabricated conductors showed a very less electrical loss with higher frequency range which in turn assigned to the roughness present in the lower side of the nanoparticles because of better packing may allow opportunities for low-temperature fabrication of anten-

nas and sub-THz metamaterials with the improved performance [39].

AgNPs can be utilised as a silver paste in the electrodes due to their high conducting nature. It is also used as conductive fillers in electronically conductive adhesives (ECAs). A few of the research groups have prepared the AgNPs by reducing the silver nitrate with ethanol in polyvinylpyrrolidone (PVP) [40]. Different reaction conditions have been tuned like PVP concentration, reaction time, and reaction temperature. In this method, PVP prevents aggregation; and also increases the nucleation rate spontaneously and simultaneously decreases the size of the silver nanoparticles. Ethanol is used as the reducing agent to adjust the viscosity of the ECAs. The produced AgNPs with the chemical reduction method showed very fine dispersion and narrow size distribution. Ethanol is also used for the re-dispersing of AgNPs. The absorption peak was recorded at 410 nm, which is an indicator of the

**4.2 In electronically conductive adhesives**

**224**

quantum size effect of the AgNPs, which is occurring in the absorption property of AgNPs. It is also summarised that the size of the AgNP has been decreased with an increase in the concentration of silver nitrate, the increase in reaction temperature, and the reaction time.

Researchers have synthesised AgNPs, silver nanorods, and epoxy resins containing high-performance electrically conductive adhesives (ECAs) using a novel preparation method. The synthesised nanoparticles and nanorods were dispersed well, with the absence of agglomeration in the matrix. The volume electrical resistivity tests determine the volume electrical resistivity of the ECA was close correlates with the various sintering temperatures and time and time, and the ECA could achieve the volume electrical resistivity of (3–4) × 9 10–5 Ω after sintering at 160 °C for 20 min. Hence, they found that the synthesised and prepared ECA to tend to achieve low-temperature sintering and showed excellent electrical, thermal, and mechanical properties [40]. **Nano metal particles such as Ag, Cu, Zn, and Au are particularly useful for electrical circuitry development because nano-sized metal particles can be shielded from inks and can also be used to boost electrical conductivity. Uniformly formed AgNPs are capable of exhibiting improved electrical conductivity, which makes electronic stuff beneficial. Films with sufficiently smooth and continuous surface morphology may be manufactured by adding AgNPs at a level of 0.05 g/100 g (0.05 per cent) in the CS-GL matrix. It has also demonstrated desirable mechanical strength for industrial packaging. CS-GL-AgNPs at 0.1 g/100 g (0.1 per cent) amount of film proved to be a promising protective packaging material that could increase the shelf life of red grapes by 14 days.**

A study [41] reported a simple method to manufacture surface improved fluorescence spectroscopy (SEFS) substrates based on highly sensitive superhydrophobic Ag nanorods (AgNR) arrays using the glancing angle deposition method at 133 K substrate temperature and resultant coating of molecules of heptadecafluoro-1-decanethiol (HDFT). SEFS substrates display more than 3 times greater fluorescence signal amplification than traditional AgNR films in the HDFT coated superhydrophobic AgNR arrays (In **Figure 4**).
