scholarly journals Towards electrically conductive, self-healing materials

2007 ◽  
Vol 4 (13) ◽  
pp. 359-362 ◽  
Author(s):  
Kyle A Williams ◽  
Andrew J Boydston ◽  
Christopher W Bielawski

A novel class of organometallic polymers comprising N -heterocyclic carbenes and transition metals was shown to have potential as an electrically conductive, self-healing material. These polymers were found to exhibit conductivities of the order of 10 −3  S cm −1 and showed structurally dynamic characteristics in the solid-state. Thin films of these materials were cast onto silicon wafers, then scored and imaged using a scanning electron microscopy (SEM). The scored films were subsequently healed via thermal treatment, which enabled the material to flow via a unique depolymerization process, as determined by SEM and surface profilometry. A method for incorporating these features into a device that exhibits electrically driven, self-healing functions is proposed.

2013 ◽  
Vol 774-776 ◽  
pp. 824-827
Author(s):  
Fu Tong Chu ◽  
Chuan Li, ◽  
Li Jun He ◽  
Xing Zhao Liu

In this paper, we report on the preparation and characterization of polyimide (PI) thin films through vapor deposition polymerization (VDP). PI thin films were formed by vapour co-deposition of the precursor monomers pyromellitic dianhydride (PMDA) and 4,4-oxydianiline (ODA) following a thermal treatment at a temperature of over 300°C. The effects of the polymerization temperature on the characterization of PI films were investigated using scanning electron microscopy and Fourier transform infrared spectroscopy. The results showed that the deposited polyamic acid (PAA, a precursor of polyimide) with imidization in the temperature interval of 300-400°C are smooth, uniformly thick and form without shrinkage.


Author(s):  
M. H. Kelley ◽  
J. Unguris ◽  
R. J. Celotta ◽  
D. T. Pierce

By measuring the spin polarization of secondary electrons generated in a scanning electron microscope, scanning electron microscopy with polarization analysis (SEMPA) can directly image the magnitude and direction of a material’s magnetization. Because the escape depth of the secondaries is only on the order of 1 nm, SEMPA is especially well-suited for investigating the magnetization of ultra-thin films and surfaces. We have exploited this feature of SEMPA to study the magnetic microstrcture and magnetic coupling in ferromagnetic multilayers where the layers may only be a few atomic layers thick. For example, we have measured the magnetic coupling in Fe/Cr/Fe(100) and Fe/Ag/Fe(100) trilayers and have found that the coupling oscillates between ferromagnetic and antiferromagnetic as a function of the Cr or Ag spacer thickness.The SEMPA apparatus has been described in detail elsewhere. The sample consisted of a magnetic sandwich structure with a wedge-shaped interlayer as shown in Fig. 1.


Author(s):  
Debbie G. Jones ◽  
Albert P. Pisano

A novel fabrication process is presented to create ultra thick ferromagnetic structures in silicon. The structures are fabricated by electroforming NiFe into silicon templates patterned with deep reactive ion etching (DRIE). Thin films are deposited into photoresist molds for characterization of an electroplating cell. Results show that electroplated films with a saturation magnetization above 1.6 tesla and compositions of approximately 50/50 NiFe can be obtained through agitation of the electrolyte. Scanning electron microscopy (SEM) images show that NiFe structures embedded in a 500 μm thick silicon wafer are realized and the roughening of the mold sidewalls during the DRIE aids in adhesion of the NiFe to the silicon.


2003 ◽  
Vol 17 (04n06) ◽  
pp. 899-904 ◽  
Author(s):  
A. VECCHIONE ◽  
M. GOMBOS ◽  
C. TEDESCO ◽  
A. IMMIRZI ◽  
L. MARCHESE ◽  
...  

NdSr 2 RuCu 2 O x material has been prepared as polycrystalline powder by solid state reaction. The compound has been investigated by synchrotron x-ray powder diffraction and scanning electron microscopy. The experimental results show that the average crystal structure is a disordered cubic perovskite with Nd and Sr cations occupying the same site and the same substitution is found for Cu and Ru atoms. A comparison between the crystal structure and morphology of this compound and the superconducting tetragonal GdSr 2 RuCu 2 O 8 is also discussed.


2013 ◽  
Vol 832 ◽  
pp. 128-131
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim

Titania or titanium dioxide (TiO2) thin film has been synthesized via sol-gel method with monoethanolamine (MEA) as a catalyst. The mixing of titanium butoxide as a precursor, ethanol as a solvent and MEA were stirred using magnetic stirrer under ambient temperature [. The TiO2solution prepared then was deposited on SiO2substrates using spin-coater and the coated films were annealed at 600°C. Finally, both before and after annealed TiO2thin films were characterized using Field Emission Scanning Electron Microscopy (FESEM). The obtained results show the different TiO2particles formation before and after annealed.


2011 ◽  
Vol 183-185 ◽  
pp. 1837-1841
Author(s):  
Lei Sha ◽  
Yan Lai Wang ◽  
Shi Liang Ban

CuInSe2 thin films were obtained by selenization of the Cu-In precursors in the atmosphere of Se vapour, which were prepared on stainless steel and titanium substrates by electrodeposition. The films were characterized by XRD, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The respective influences of composition, phases and surface morphology of Cu-In precursors on indium loss were investigated. The results indicate that the indium loss occurs in selenization process because of volatile In2Se arising. The indium loss is less in selenization process of Cu-In precursors contained CuIn, Cu2In and In phases.


2007 ◽  
Vol 546-549 ◽  
pp. 1699-1702
Author(s):  
Xi Ying Zhou ◽  
Liang He ◽  
Yan Hui Liu

Al-Cu-Fe quasicrystals powder was used to prepare the thin films on the surface of the A3 steel by the means of DMD-450 vacuum evaporation equipment. The thin films with different characterization were obtained through different parameters. The microstructures of the thin films were analyzed by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Additionally, the nano-hardness and the modulus of the films are tested by MTS and Neophot micro-hardness meter. The results showed that the modulus of the films was about 160GPa. Nano hardness of the films was about 7.5 Gpa. The films consisted of CuAl2, AlCu3. The thickness and the micro-hardness of the films are improved. In same way, with the increase of the electric current, the thickness and the hardness of the films are also improved. Along with increase of the time and the electric current, the wear behavior of the films was improved. To some extent, the microstructure of films contained the quasicrystal phase of Al65Cu20Fe15.


1990 ◽  
Vol 04 (05) ◽  
pp. 369-373 ◽  
Author(s):  
Y. Z. ZHANG ◽  
L. LI ◽  
Y. Y. ZHAO ◽  
B. R. ZHAO ◽  
Y. G. WANG ◽  
...  

A planar dc magnetron sputtering device was used to prepare high T c and high J c YBCO thin films. Both single crystal and polycrystal thin films were successfully grown on (100) oriented LaAlO 3 substrates. Zero resistance temperature T c0 = 92.3 K and critical current density J c (0) = 3.82 × 106 A/cm 2 at 77 K was obtained. The films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).


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