Programmable single-layer polymer films for millimeter and sub-millimeter self-folding origami

2020 ◽  
Author(s):  
Derosh George ◽  
Marc Madou ◽  
Edwin A. Peraza-Hernandez
Keyword(s):  
Polymer Films ◽  
Single Layer

Multi-Layer Coating of Ultrathin Polymer Films on Nanoparticles of Alumina by a Plasma Treatment

2001 ◽  
Vol 635 ◽  
Author(s):  
Donglu Shi ◽  
Zhou Yu ◽  
S. X. Wang ◽  
Wim J. van Ooij ◽  
L. M. Wang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Polymer Films ◽  
Ultrathin Films ◽  
Plasma Polymerization ◽  
Single Layer ◽  
Process Time ◽  
Transmission Electron ◽  
Ultrathin Polymer Films ◽  
Secondary Ion ◽  
Layer Coating

AbstractMulti-layer ultrathin polymer films have been deposited on the surfaces of nanoparticles of alumina using a plasma polymerization treatment. The nanoparticles ranged from 10-150 nm in spherical shapes. High-resolution transmission electron microscopy (HRTEM) experiments showed that an extremely thin film of the pyrrole layer (10-20 Å) was uniformly deposited on the surfaces of the nanoparticles. In particular, the particles of all sizes (10-150 nm) exhibited equally uniform ultrathin films indicating well-dispersed nanoparticles in the fluidized bed during the plasma treatment. After single layer coating, hexamethyldisiloxane (HMDSO) was coated again as a second layer onto the surface of pyrrole. Subsequently, a third layer of pyrrole was coated on the top of HMDSO film completing the multi-layer coating process. Time-of-Flight Secondary ion mass spectroscopy (TOFSIMS) experiments confirmed the deposition of these multi-layer thin films on the nanoparticles. The deposition mechanisms and the effects of plasma treatment parameters are discussed.

Electropolymerization of aniline and some of its derivatives

1989 ◽  
Vol 54 (12) ◽  
pp. 3154-3161 ◽  
Author(s):  
Ludmila Dempírová ◽  
Zdena Adamcová
Keyword(s):  
Polymer Films ◽  
Electrochemical Behaviour ◽  
Oxidation Mechanism ◽  
Single Layer ◽  
Amino Group ◽  
Methyl Substituent ◽  
Pt Electrode ◽  
Pt Electrodes ◽  
Electro Oxidation ◽  
Acetonitrile Medium

The effect of substitution on the aromatic ring of aniline and in its amino group on the potential of polymerization in aqueous medium and on the charge passed during polymerization was studied. The formation of polymer films on the working electrode and their electrochromic changes were also examined. From the electro-oxidation of aniline, the number of reversible and irreversible steps, the number of electrons exchanged and the type of oxidation mechanism were found. Thickness of a single layer of polyaniline, formed by cycling the potential in the range –0.2 V, +1.4 V(vs SCE) at a polarization rate of 5 mV/s, was estimated considering the oxidation mechanism of aniline. The electrochemical behaviour of aniline in anhydrous acetonitrile medium was also studied. It was found by blocking the m- and p-positions in aniline by a methyl substituent that polymerization of aniline occurs through the p-position. The porosity of the polymer films was estimated from the diffusion coefficient values for 1.10-3M K3[Fe(CN)]6 in 0.1M-KCl calculated from the Randles-Sevcik equation for measurements on Pt electrodes with a polymer film, compared with the tabulated values for a bare Pt electrode.

Electroluminescence from single layer molecularly doped polymer films

1995 ◽  
Vol 67 (1) ◽  
pp. 175-182 ◽  
Author(s):  
G. E. Johnson ◽  
K. M. McGrane ◽  
M. Stolka
Keyword(s):  
Polymer Films ◽  
Single Layer ◽  
Doped Polymer

Crystalline order to a resolution of 4.7 A in the sheath of Methanospirilium hungatii: A cross-beta structure

1984 ◽  
Vol 42 ◽  
pp. 214-215
Author(s):  
Murray Stewart ◽  
T.J. Beveridge ◽  
D. Sprott
Keyword(s):  
Cell Wall ◽  
Single Layer ◽  
Uranyl Acetate ◽  
Optical Diffraction ◽  
Tube Axis ◽  
Basic Subunit ◽  
Beta Structure ◽  
Diffraction Patterns ◽  
Protein Treatment ◽  
General Appearance

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.

Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

1990 ◽  
Vol 48 (3) ◽  
pp. 430-431
Author(s):  
Maria Anna Pabst
Keyword(s):  
Apis Mellifera ◽  
Distal Part ◽  
Cell Layer ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Distal Segment ◽  
Compound Eyes ◽  
Thin Sections ◽  
Ultrastructural Studies ◽  
Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

Gum arabic helps prepare better lacey polymer films for specimen support in electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 240-241
Author(s):  
Shailesh R. Sheth ◽  
Jayesh R. Bellare
Keyword(s):  
Electron Microscopy ◽  
Polymer Films ◽  
Gum Arabic ◽  
Complete Removal ◽  
Ammonium Bromide ◽  
Release Agent ◽  
Astigmatism Correction ◽  
Long Time ◽  
Micro Holes ◽  
Cetyl Trimethyl Ammonium

Specimen support and astigmatism correction in Electron Microscopy are at least two areas in which lacey polymer films find extensive applications. Although their preparation has been studied for a very long time, present techniques still suffer from incomplete release of the film from its substrate and presence of a large number of pseudo holes in the film. Our method ensures complete removal of the entire lacey film from the substrate and fewer pseudo holes by pre-treating the substrate with Gum Arabic, which acts as a film release agent.The method is based on the classical condensation technique for preparing lacey films which is essentially deposition of minute water or ice droplets on the substrate and laying the polymer film over it, so that micro holes are formed corresponding to the droplets. A microscope glass slide (the substrate) is immersed in 2.0% (w/v) aq. CTAB (cetyl trimethyl ammonium bromide)-0.22% (w/v) aq.

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