Radiation-chemical synthesis of thermo- and pH-sensitive antibacterial silver/poly(N-isopropilacrylamide-co-itaconic acid) nanocomposites.

U okviru ove doktorske disertacije izvedena je radijaciono-hemijska sinteza i karakterizacija novih nanokompozita na bazi umreţenih polimernih matrica N-izopropilakrilamida (NiPAAm) i itakonske kiseline (IK) i nanočestica srebra (Ag/P(NiPAAm/IK)). Za sintezu nanokompozita je korišćena radiolitička metoda koja omogućava umreţavanje i fino podešavanje svojstava nosača tj. polimerne matrice, ali i formiranje nanočestica srebra ţeljenih svojstava unutar polimerne matrice (in situ sinteza). Radiolitička metoda sinteze je izvedena pod dejstvom gama zračenja na kobaltnom (60Co) izvoru. Sintetisani uzorci su podvrgnuti detaljnoj fizičko-hemijskoj karakterizaciji u cilju dobijanja informacija o polimernim matricama kao nosačima i nanočesticama srebra kao nanopuniocima, ali i u cilju ispitivanja njihovog sinergističkog dejstva u nanokompozitnim sistemima. Morfologija umreţenih sistema je ispitana primenom skenirajuće elektronske mikroskopije (SEM) i mikro kompjuterizovane topografije (mikro-CT), a studija bubrenja praćenjem kinetike bubrenja u medijumima različitih pH-vrednosti i temperature, pri čemu su simulirani fiziološki uslovi. Utvrđeno je da prisustvo itakonske kiseline i inkorporacija nanočestica srebra utiču na morfologiju nanokompozita, parametre polimerne mreţe, kao i na kapacitet bubrenja. Optička svojstva nanokompozita su ispitana metodom spektroskopije u ultraljubičastoj i vidljivoj oblasti spektra (UV-Vis) i teorijskim modelovanjem primenom MiePlot 3.4 programskog paketa čiji je algoritam zasnovan na Mie-ovoj teoriji. U apsorpcionim spektrima je zapaţena karakteristična plazmonska apsorpcija sa maksimumom u opsegu od 390 nm do 412 nm, dok je modelovanjem određeno da se vrednost prečnika nanočestica srebra kreće između 6,8 nm i 16,2 nm...In this study, radiation-chemical synthesis and characterization of the novel nanocomposite systems based on silver nanoparticles (AgNPs) and crosslinked copolymer matrix of N-isopropylacrylamide (NiPAAm) and itaconic acid (IA) (Ag/P(NiPAAm/IA)) were performed. Radiolytic method, which is used for synthesis, enables fine tuning of properties of polymer matrix as a carrier, as well as formation of the silver nanoparticles with desired properties within polymer matrix (in situ synthesis). The radiolytic synthesis method is carried out by gamma irradiation at a cobalt (60Co) radiation facility. Synthesized samples were undergo to detailed physico-chemical characterization in order to obtain information about polymer matrix as a carrier and silver nanoparticles as a nanofillers, but also to examine their synergistic effects in the nanocomposite systems. Morphology of the crosslinked systems was performed by scanning electron microscopy (SEM) and micro computerized topography (micro-CT), while swelling study was performed by monitoring the swelling kinetics in the swelling media with different pH and temperature, i.e. in simulated physiological conditions. It has been shown that the addition of itaconic acid and incorporation of AgNPs have influences on the morphology, network parameters as well as on the swelling capacity. The optical properties of the nanocomposites were investigated by ultraviolet–visible spectroscopy (UV-Vis) and theoretical modeling using MiePlot 3.4 software package, with algorithm based on Mie's theory. Obtained absorption spectra exhibit the characteristic plasmon peak with maxima between 390 nm and 412 nm, while the modeling has shown that the mean size of the silver nanoparticles was in the range between 6.8 nm and 16.2 nm..

Non-isothermal kinetics of dehydration of Ag/PVA hydrogel nanocomposite synthesized by Γ-irradiation

In this study, the non-isothermal kinetics of dehydration of γ-radiolytically synthesized PVA and Ag/PVA nanocomposite hydrogels was investigated by thermogravimetric analysis (TGA). Kinetic analysis was performed by applying different model fitting and model-free kinetic analysis to estimate kinetic parameters, the activation energy (Ea) and pre-exponential factor (A). The analysis showed that incorporation of silver nanoparticles (Ag NPs) into PVA hydrogel matrix has influence on kinetic parameters of dehydration process.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Poly(NiPAAm-co-IA) hydrogels synthesized by y-irradiation: swelling behavior in water

In this study, N-isopropylacrylamide/itaconic acid copolymeric (poly(NiPAAm-coIA)) hydrogels were synthesized by γ-irradiation induced simultaneous polymerization and crosslinking of monomers. The influence of comonomer concentration (IA) on the swelling behavior in water was investigated. The results showed that values of network parameters increase with an increase of IA, and that the swelling transport mechanism is a non-Fickian transport.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Structural characteristics of Ag nanoparticles synthesized in situ within pnipaam hydrogel by γ-irradiation

In this work, silver nanoparticles (AgNPs) are synthesized within thermo responsive poly(N-isopropylacrylamide) (PNiPAAm) hydrogels of different concentrations, by γ-irradiation. The UV-Vis plasmon absorption characterization of AgNPs and its modeling using Mie theory showed that their diameters are less than 20 nm. The X-ray diffraction (XRD) data are consistent with the face centered cubic (FCC) crystal structure of bulk metallic Ag. The negative lattice strain (lattice contraction) was observed for the samples where the AgNPs are incorporated in the xerogel solid matrix of highest polymer concentration (15 wt.% PNiPAAm). The lattice parameter values are found to be higher than the bulk lattice parameter of Ag for larger nanoparticles formed in 5 wt.% PNiPAAm, whereas the crystallites were under tensile stress. On the other hand, for smaller nanoparticles formed in 15 wt.% PNiPAAm, crystallites were under compression stress (negative stress) whereby the lattice is contracted

Ag-pva/cmc blend hydrogel nanocomposite synthesized by γ-irradiation followed by freeze/thawing method

Poly(vinyl alcohol)/carboxymethyl-chitosan (PVA/CMC) blend hydrogels were synthesized by γ-radiolysis followed by freeze/thawing (FT). Previous, the water-solubility of chitosan (CS) was obtained by γ-radiolytic acidic degradation. CMC molecular weight characterization was performed by a Zetasizer. The fluorescence measurements confirmed the presence of CMC in the PVA/CMC blend hydrogels. In situ preparation of Ag nanoparticles (AgNPs) in PVA/CMC blend hydrogel matrices has been performed exposing hydrogels, swollen in AgNO3 solution, to γ-irradiation. The mathematical models applied for determination swelling kinetics showed that the initial concentrations of CMC and AgNPs directly have influence on the swelling parameters of Ag-PVA/CMC nanocomposites. Diffusion characteristics, determined by different diffusion models (Early Time (ET), Late Time (LT) and Etters (E)) are less due to the presence of AgNPs

Gamma irradiation induced synthesis of PbS/PVA hydrogel nanocomposite

This work describes radiolytic in situ incorporation of lead sulfide nanoparticles (PbS NPs) in poly(vinyl alcohol) (PVA) hydrogel. Optical, structural, swelling and diffusion properties of prepared PbS/PVA hydrogel nanocomposite were investigated. Obtained results indicate formation of PbS NPs with a cubic crystal structure and diameter around 3 nm. Incorporation of PbS NPs in PVA hydrogel causes a change in the swelling and diffusion properties

Physicochemical characteristics of gamma irradiation crosslinked poly(vinyl alcohol)/magnetite ferrogel composite

Magnetic field sensitive gels, ferrogels, are new promising class of hydrogels. The coupling of hydrogels and magnetic particles has potential application in soft actuators, such as artificial muscles, or for hyperthermia application. In this study, the composite of magnetite particles (Fe3O4) and poly(vinyl alcohol) (PVA) hydrogel is developed using gamma irradiation as a crosslinking agent. PVA and Fe3O4 were chosen due to their well-established biocompatibility, radiation crosslinking potential (PVA), mild magnetic properties and the Curie point near desired heating temperature range (Fe3O4). Physicochemical characteristics of these systems show the effect of the presence of particles in the process of radiation-induced crosslinking. Obtained PVA/Fe3O4 ferrogel composite has greater swelling capacity, activation energy of dehydration and dehydration rate compared to PVA hydrogel, crosslinked under the same conditions

Radiation-chemical synthesis of thermo- and pH-sensitive antibacterial silver/poly(N-isopropilacrylamide-co-itaconic acid) nanocomposites.

U okviru ove doktorske disertacije izvedena je radijaciono-hemijska sinteza i karakterizacija novih nanokompozita na bazi umreţenih polimernih matrica N-izopropilakrilamida (NiPAAm) i itakonske kiseline (IK) i nanočestica srebra (Ag/P(NiPAAm/IK)). Za sintezu nanokompozita je korišćena radiolitička metoda koja omogućava umreţavanje i fino podešavanje svojstava nosača tj. polimerne matrice, ali i formiranje nanočestica srebra ţeljenih svojstava unutar polimerne matrice (in situ sinteza). Radiolitička metoda sinteze je izvedena pod dejstvom gama zračenja na kobaltnom (60Co) izvoru. Sintetisani uzorci su podvrgnuti detaljnoj fizičko-hemijskoj karakterizaciji u cilju dobijanja informacija o polimernim matricama kao nosačima i nanočesticama srebra kao nanopuniocima, ali i u cilju ispitivanja njihovog sinergističkog dejstva u nanokompozitnim sistemima. Morfologija umreţenih sistema je ispitana primenom skenirajuće elektronske mikroskopije (SEM) i mikro kompjuterizovane topografije (mikro-CT), a studija bubrenja praćenjem kinetike bubrenja u medijumima različitih pH-vrednosti i temperature, pri čemu su simulirani fiziološki uslovi. Utvrđeno je da prisustvo itakonske kiseline i inkorporacija nanočestica srebra utiču na morfologiju nanokompozita, parametre polimerne mreţe, kao i na kapacitet bubrenja. Optička svojstva nanokompozita su ispitana metodom spektroskopije u ultraljubičastoj i vidljivoj oblasti spektra (UV-Vis) i teorijskim modelovanjem primenom MiePlot 3.4 programskog paketa čiji je algoritam zasnovan na Mie-ovoj teoriji. U apsorpcionim spektrima je zapaţena karakteristična plazmonska apsorpcija sa maksimumom u opsegu od 390 nm do 412 nm, dok je modelovanjem određeno da se vrednost prečnika nanočestica srebra kreće između 6,8 nm i 16,2 nm...In this study, radiation-chemical synthesis and characterization of the novel nanocomposite systems based on silver nanoparticles (AgNPs) and crosslinked copolymer matrix of N-isopropylacrylamide (NiPAAm) and itaconic acid (IA) (Ag/P(NiPAAm/IA)) were performed. Radiolytic method, which is used for synthesis, enables fine tuning of properties of polymer matrix as a carrier, as well as formation of the silver nanoparticles with desired properties within polymer matrix (in situ synthesis). The radiolytic synthesis method is carried out by gamma irradiation at a cobalt (60Co) radiation facility. Synthesized samples were undergo to detailed physico-chemical characterization in order to obtain information about polymer matrix as a carrier and silver nanoparticles as a nanofillers, but also to examine their synergistic effects in the nanocomposite systems. Morphology of the crosslinked systems was performed by scanning electron microscopy (SEM) and micro computerized topography (micro-CT), while swelling study was performed by monitoring the swelling kinetics in the swelling media with different pH and temperature, i.e. in simulated physiological conditions. It has been shown that the addition of itaconic acid and incorporation of AgNPs have influences on the morphology, network parameters as well as on the swelling capacity. The optical properties of the nanocomposites were investigated by ultraviolet–visible spectroscopy (UV-Vis) and theoretical modeling using MiePlot 3.4 software package, with algorithm based on Mie's theory. Obtained absorption spectra exhibit the characteristic plasmon peak with maxima between 390 nm and 412 nm, while the modeling has shown that the mean size of the silver nanoparticles was in the range between 6.8 nm and 16.2 nm..

Radiation-chemical synthesis of thermo- and pH-sensitive antibacterial silver/poly(N-isopropilacrylamide-co-itaconic acid) nanocomposites.

U okviru ove doktorske disertacije izvedena je radijaciono-hemijska sinteza i karakterizacija novih nanokompozita na bazi umreţenih polimernih matrica N-izopropilakrilamida (NiPAAm) i itakonske kiseline (IK) i nanočestica srebra (Ag/P(NiPAAm/IK)). Za sintezu nanokompozita je korišćena radiolitička metoda koja omogućava umreţavanje i fino podešavanje svojstava nosača tj. polimerne matrice, ali i formiranje nanočestica srebra ţeljenih svojstava unutar polimerne matrice (in situ sinteza). Radiolitička metoda sinteze je izvedena pod dejstvom gama zračenja na kobaltnom (60Co) izvoru. Sintetisani uzorci su podvrgnuti detaljnoj fizičko-hemijskoj karakterizaciji u cilju dobijanja informacija o polimernim matricama kao nosačima i nanočesticama srebra kao nanopuniocima, ali i u cilju ispitivanja njihovog sinergističkog dejstva u nanokompozitnim sistemima. Morfologija umreţenih sistema je ispitana primenom skenirajuće elektronske mikroskopije (SEM) i mikro kompjuterizovane topografije (mikro-CT), a studija bubrenja praćenjem kinetike bubrenja u medijumima različitih pH-vrednosti i temperature, pri čemu su simulirani fiziološki uslovi. Utvrđeno je da prisustvo itakonske kiseline i inkorporacija nanočestica srebra utiču na morfologiju nanokompozita, parametre polimerne mreţe, kao i na kapacitet bubrenja. Optička svojstva nanokompozita su ispitana metodom spektroskopije u ultraljubičastoj i vidljivoj oblasti spektra (UV-Vis) i teorijskim modelovanjem primenom MiePlot 3.4 programskog paketa čiji je algoritam zasnovan na Mie-ovoj teoriji. U apsorpcionim spektrima je zapaţena karakteristična plazmonska apsorpcija sa maksimumom u opsegu od 390 nm do 412 nm, dok je modelovanjem određeno da se vrednost prečnika nanočestica srebra kreće između 6,8 nm i 16,2 nm...In this study, radiation-chemical synthesis and characterization of the novel nanocomposite systems based on silver nanoparticles (AgNPs) and crosslinked copolymer matrix of N-isopropylacrylamide (NiPAAm) and itaconic acid (IA) (Ag/P(NiPAAm/IA)) were performed. Radiolytic method, which is used for synthesis, enables fine tuning of properties of polymer matrix as a carrier, as well as formation of the silver nanoparticles with desired properties within polymer matrix (in situ synthesis). The radiolytic synthesis method is carried out by gamma irradiation at a cobalt (60Co) radiation facility. Synthesized samples were undergo to detailed physico-chemical characterization in order to obtain information about polymer matrix as a carrier and silver nanoparticles as a nanofillers, but also to examine their synergistic effects in the nanocomposite systems. Morphology of the crosslinked systems was performed by scanning electron microscopy (SEM) and micro computerized topography (micro-CT), while swelling study was performed by monitoring the swelling kinetics in the swelling media with different pH and temperature, i.e. in simulated physiological conditions. It has been shown that the addition of itaconic acid and incorporation of AgNPs have influences on the morphology, network parameters as well as on the swelling capacity. The optical properties of the nanocomposites were investigated by ultraviolet–visible spectroscopy (UV-Vis) and theoretical modeling using MiePlot 3.4 software package, with algorithm based on Mie's theory. Obtained absorption spectra exhibit the characteristic plasmon peak with maxima between 390 nm and 412 nm, while the modeling has shown that the mean size of the silver nanoparticles was in the range between 6.8 nm and 16.2 nm..

Radiolytic incorporation of gold nanoparticles into PVA hydrogel

This work describes the Au-PVA hydrogel nanocomposites synthesized by radiolytic in situincorporation of gold nanoparticles (Au NPs) into poly(vinyl alcohol) (PVA) hydrogel. Synthesis of nanocomposites was conducted as two-step gamma irradiation induced process. In the first step, the crosslinking of polymer chains occurs and PVA hydrogel with a large number of pores was obtained. In the second step, these pores serve as nanoreactors for the formation of Au NPs. The presence of Au NPs was confirmed by absorption spectra, while morphological and structural analysis reveals the spherical shape of Au NPs, with the diameter around 15 nm and fcccrystal structure. The structural parameters of xerogels indicate that incorporation of Au NPs induce the expansion of polymer network. Long-time stability of Au-PVA hydrogel nanocomposites is caused by interactions between the surface of Au NPs and OH groups of PVA chains.Physical chemistry 2016 : 13th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-30 September 201