Films of pure polyvinyl alcohol (PVA) and its manganese chloride filled polymer composite film (MPVA) were prepared and their optical properties were evaluated. XRD, UV-vis, and FTIR analyses reveal that there is strong interaction between polyvinyl alcohol and manganese chloride. Interchain separation (R) for pristine PVA and MPVA composite films was found as 5.60 and 4.69 Ǻ , respectively, thus showing polymer chains are more compact in MPVA. Optical band gap of polyvinyl alcohol was reduced on incorporation of manganese chloride in polyvinyl alcohol to cause approximately 2.5-fold increase in optical conductivity. Refractive index of MPVA was found to be higher than that of PVA in the visible range up to 710 nm but beyond that it became lower than that of PVA. Abbe Number was decreased on incorporation of manganese chloride to PVA with concomitant increase in dispersion energy. Urbach energy (E u ) for PVA and MPVA was found to be 0.70 and 0.82 eV, respectively. AFM study reveals formation of sunflower like assembled texture at nano-scale level in MPVA film and it exhibits a higher root mean square (RMS) roughness and absorbance than those of pristine PVA film. Average oscillation wavelength (λ 0 ) was found to be close to the respective absorption edge; and MPVA showed higher oscillation strength (S 0 ) than that of PVA. POLYM. COMPOS., 40:E765-E775, 2019.POLYMER COMPOSITES-2019 FIG. 1. XRD record of (a) PVA film and (b) MPVA film; Inset shows the XRD record of manganese chloride. E766 POLYMER COMPOSITES-2019 DOI 10.1002/pc FIG. 2. FTIR spectra of (a) pure PVA and (b) MPVA films. The magnified version of spectra in the box is shown at the top.
PVA/Co/Ag film has been prepared by sputtering Co followed by Ag in polyvinyl alcohol (PVA) matrix film by IBS technique, so as to get a 9 nm (thick) layer of Co metal nanoparticles followed by a protective 4 nm (thick) layer of Ag nanoparticles. Grazing incidence x-ray diffraction (GIXRD) pattern of the film reveals the formation of nanocrystalline Co with hcp phase. GIXRD pattern also indicates that there is no change in the crystalline structure of PVA even after sputtering of the metallic nanoparticles. The average particle size of Co nanoparticles as evaluated using Scherrer formula is found to be about 2.64 nm. UV visible absorption pattern of the film sample showed SPR peaks of Co and Ag metals in their nano size level embedded in the PVA matrix system. XPS study confirms the metallic nature of Co and Ag nanoparticles; and the depth profiling study reveals that both the metal nanoparticles have been embedded in the PVA matrix system. Surface morphology of such film has been studied using AFM; and the magnetic behaviour of the film studied by using MOKE shows soft ferromagnetic behaviour in this PVA/Co/Ag system.
In this paper, we report the embedment of Cobalt (Co) nanoparticles by ion beam sputtering (IBS) in poly(vinyl alcohol) (PVA) substrate to prepare nanocomposite film. The Co film of 5 nm was deposited on PVA by IBS technique. Formation of nanocrystalline Co with hcp phase is revealed in GIXRD pattern of the film which also indicates that there is no change in the crystalline structure of PVA even after sputtering of the metallic nanoparticles. The average particle size of Co nanoparticles as evaluated using Scherer formula is found to be about 2 nm. UVVis absorption spectrum of the film showed SPR peaks of Co metal in their nano size level embedded in the PVA matrix system. XPS study confirms the metallic nature of Co MOKE studies show that the nanocomposite film is ferromagnetic with Hc || of. 42.8 Oe.
The effect of confinement between two metallic layers on the melting behavior of a 13 monolayer cadmium arachidate (CdA) Langmuir-Blodgett (LB) multilayer has been studied. Temperature dependent diffraction measurements provide information about structural changes occurring in the film plane as well as in the out-of-plane direction. X-ray standing waves have been used to achieve depth selectivity in diffraction measurements. It is found that the difference in melting behavior of the surface and the bulk, which is observed in the film with free surface, disappears in the case of confined films; while the free surface transforms to hexaticlike phase via an intermediate smectic phase, confinement results in disappearance of this phase, and the sequence of transformations in the bulk and the interfacial regions becomes identical. Some anisotropy between (01 + 11¯) and (10) directions remains, with coherence along (10) direction decreasing at a faster rate. The confinement between metallic layers also significantly reduces the tilting of the chains observed at higher temperature. Further, both in the case of film with free surface and confined films, melting at the surface/interface occurs at a lower temperature as compared to the bulk.
Ultrasmall nanoparticles (USNs) (nanoparticles with hydrodynamic diameter <10 nm) are being widely developed pre‐clinically and started to emerge in clinical trials over the last decade. Most of these USNs display the same features including short retention time in the blood, rapid renal clearance, and relie on passive targeting strategy to reach the tumor. Through this review, the development of AGuIX USNs is focused on because of their clinical usages as passively targeted USN but also because of their possible biofunctionalizations with peptides and monoclonal antibodies which are validated in various pre‐clinical tumor models. As a result, the authors reviewed all the current biofunctionalization strategies that can be employed and confirmed based on a meta‐analysis of the literature that biofunctionalized USNs pharmacokinetic and biodistribution profiles are dictated by the USNs and not the active targeting moiety. Additionally, it is demonstrated that such active targeting strategy improves the tumor targeting efficiency of the AGuIX USN but also increases their tumor retention time in comparison to the passively targeted AGuIX USNs, which may lead to an opportunity to reduce the number of injections/expend the therapeutic benefit of the drug product.
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