scholarly journals Fabrication and Characterization of Antibacterial-active Multilayer Films Based on Keggin Polyoxometalates and Methylene Blue

2010 ◽  
Vol 65 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Dan Chen ◽  
Jun Peng ◽  
Haijun Pang ◽  
Pengpeng Zhang ◽  
Yuan Chen ◽  
...  

Two kinds of multilayer films based on Keggin polyoxometalates α-[SiW12O40]4−/α- [PMo12O40]3− and methylene blue have been prepared via the layer-by-layer (LBL) self-assembly technique. The multilayer films were characterized by UV/Vis spectra, atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS). The cyclic voltammetry (CV) measurements have demonstrated that the electrochemical properties of POMs are maintained in the LBL films. The antibacterial activity of the LBL films has also been investigated, which shows a distinct antibacterial effect against Escherichia coli.

10.26524/jap9 ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Jayamurugan P ◽  
Manoharan D ◽  
Ramadevi K ◽  
Upendar Reddy K ◽  
Subba Rao Y V

The nanocolloidal solution has been spin coated on the substrate layer-by-layer, a self-assembly technique has used to form the multilayer thin films. The optical and structural properties of self-assembled multilayer thin films were characterized by UV-visible, photoluminescence, X-ray diffraction and atomic force microscopy


2008 ◽  
Vol 8 (3) ◽  
pp. 1248-1253 ◽  
Author(s):  
Yu-Qi Zhang ◽  
Li-Hua Gao ◽  
Ke-Zhi Wang ◽  
Hong-Jun Gao ◽  
Ye-Liang Wang

A dipolar Ru(II) complex, [(bpy)2Ru(bpbh)Ru(bpy)2](ClO4)4 {where bpbh = 1,6-bis-[2-(2-pyridyl) benzimidazoyl]hexane, bpy = 2,2′-bipyridine}, was synthesized and characterized. A multilayer film of at least 18 layers was successfully prepared by alternating adsorption of H4SiW12O40 and [Ru2(bpy)4(bpbh)](ClO4)4 by electrostatic layer-by-layer self-assembly. The multilayer films were studied by ultraviolet-visible and X-ray photoelectron spectroscopy, atomic force microscopy, and cyclic voltammetry.


2011 ◽  
Vol 66 (1) ◽  
pp. 43-48
Author(s):  
Changyun Chen ◽  
Jun Peng ◽  
Yan Shen ◽  
Dan Chen ◽  
Huanqiu Zhang ◽  
...  

A luminescent multilayer film has been fabricated from the polyoxometalate anion α- [PMo12O40]3− (α-PMo12) and the cation Fuchsin Basic (FB) through an electrostatic layer-by-layer (LbL) self-assembly method and characterized by UV/Vis spectra, atomic force microscopy and X-ray photoelectron spectra. The fluorescence properties of the LbL film have also been investigated. Cyclic voltammetry measurements have demonstrated that the electrochemical properties of the polyoxometalate and FB are maintained in the multilayer film, which exhibits electrocatalytic activity for the reduction of bromate


2009 ◽  
Vol 13 (07) ◽  
pp. 774-778 ◽  
Author(s):  
Byung-Soon Kim ◽  
Young-A Son

In this study, self-assembled alternating film using poly(diallyldimethylammonium chloride) (PDDAC) and meso-tetrakis(4-carboxyphenyl)porphyrin (MTCP) was prepared as a multilayer deposition on glass substrate. This preparation technique for dye deposition may provide new feasibilities to achieve the manufacture of ultrathin films for nanotechnology application. The deposition films were characterized by UV-vis spectrophotometer and Atomic Force Microscopy (AFM) analysis. The results of UV-vis spectra showed that the absorbance characteristic of the multilayer films linearly increased with an increased number of PDDAC and MTCP bilayers. AFM analysis showed the film surface was relatively uniform and the progressive growth of layers was determined.


2020 ◽  
pp. 2050027
Author(s):  
BANDANA DAS ◽  
ALPANA BAIDYA ◽  
SANTANU MAJUMDER ◽  
RANENDU KUMAR NATH

Layer-by-layer (LbL) self-assembly is one of the unique methods for fabrication of ultra-thin film. This technique has immense application aross many fields in today’s life. In this paper, we have presented the fabrication of the thin film comprising of antifungal and antibacterial cationic dye methylene blue with negatively charged E. coli K30 bacterial polysaccharide sharing with PAH. The multilayers were characterized by UV–Vis absorption spectra and AFM. Various photophysical behaviors were investigated. Such studies provide a new light in the research of layer by layer self-assembly technique.


2014 ◽  
Vol 783-786 ◽  
pp. 1226-1231 ◽  
Author(s):  
Thiago Bezerra Taketa ◽  
Marisa Masumi Beppu

Layer-by-layer (LbL) is a bottom-up technique used for construction of films with self-assembly and self-organizing properties. In most cases, the fundamental driving force for the formation of these films is originated from the electrostatic interaction between oppositely charged species. The charged segments of polyelectrolytes behave as small building units and their orientation and position can be designed to target structures of great complexity. Furthermore, the technique enables the use of various materials, including natural polymers. In this work, we chose the cationic biopolymer chitosan (CHI) and the negative polyelectrolytes sodium alginate (ALG) and hyaluronic acid (HA). The aim of this study was to evaluate the effect of ionic strength (0 versus 200 mM) and pH (3 versus 5) on ALG/CHI and HA/CHI nanostructured multilayered thin films properties. From profilometry and atomic force microscopy (AFM) analyses, changes in thickness and roughness of the coatings were monitored. The presence of salt in polyelectrolyte solutions induced the polymer chains to adopt conformations with more loops and tails and this arrangement in solution was transmitted to films, resulting in rougher surfaces. Furthermore, the film thickness can be precisely controlled by adjusting the pH of the polyelectrolyte solution. The variation of these parameters shows that it is possible to molecularly control chemical and structural properties of nanostructured coatings, thus opening up new possibilities of application (e.g. cell adhesion).


2013 ◽  
Vol 750-752 ◽  
pp. 1630-1634
Author(s):  
Li Ping Ruan ◽  
Zhi Hua Xing

In this paper, we reported the dynamic self-assembly process of an half-sequence ionic self-complementarity peptide CH3CO-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-NH2, which could self-assemble into stable nanofibers and formed hydrogel consisting of >99% water. The dynamic self-assembly process was detected by circular dichroism (CD) and atomic force microscopy (AFM). CD spectrum revealed that the mainly contents of the peptide were regular β-sheet structure. The data indicated that though the secondary structure of the peptide formed immediately, the microstructure of the self-assembly process of the designed peptide formed slowly. AFM image illustrated that the self-assembly process was layer-by-layer assembly.


2010 ◽  
Vol 663-665 ◽  
pp. 252-255
Author(s):  
Xue Feng Li ◽  
Shao Xian Peng

A stable and high lubricant ultrathin film was fabricated by self-assembled procedure at room temperature. Thickness of the films was regularly increased with the layer-by-layer self-assembly process in which poly (acrylic acid)-ferric hydroxide (PAA-Fe(OH)3) sol as anion polyelectrolyte and photosensitive diazoresin (DR) as cationic polyelectrolyte. And the process which based on electrostatic attraction was verified by UV-vis measurement. Furthermore, the ionic bonds in the films converted to covalent bonds under UV irradiation. Finally, the surface morphology and microtribology of the films were investigated by atomic force microscopy (AFM) and friction force microscopy (FFM). The results indicate that the films are flat and uniform through the self-assembly technique and the surface friction coefficients maintain at a rather low value.


2006 ◽  
Vol 10 (07) ◽  
pp. 986-990
Author(s):  
Young-A Son ◽  
Young-Min Park ◽  
Byung-Soon Kim

A multi-layer film has been fabricated, using poly(diallyldimethylammonium chloride) ( PDDAC ) and a copper phthalocyanine ( CuPc ) dye, held together by electrostatic forces and layer-by-layer self-assembly attractions. The result of the multi-layer fabrication was characterized by UV-vis absorbance measurements and Atomic Force Microscopy (AFM). UV-vis absorption spectra of the multi-layer films increased linearly at 676 nm, which indicated that the fabrication proceeded regularly. The AFM images show that the surface of the self-assembled multi-layer was thickly covered with PDDAC / CuPc and relatively uniform.


RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 67017-67024 ◽  
Author(s):  
Wei Zhang ◽  
Guoqin Li ◽  
Xiaoying Fei ◽  
Yu Zhang ◽  
Jian Tong ◽  
...  

A novel kind of multilayer films consisting of graphene oxide and a cationic zinc phthalocyanine were fabricated through an electrostatic layer-by-layer self-assembly technique and their photoelectric conversion properties were studied in detail.


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