Dynamically Cross-Linked Polydimethylsiloxane Networks with Ambient-Temperature Self-Healing

2015 ◽  
Vol 48 (24) ◽  
pp. 8781-8788 ◽  
Author(s):  
Willi Schmolke ◽  
Norman Perner ◽  
Sebastian Seiffert
Keyword(s):  
Ambient Temperature ◽  
Self Healing

Self-healing polymers with PEG oligomer side chains based on multiple H-bonding and adhesion properties

2015 ◽  
Vol 6 (28) ◽  
pp. 5086-5092 ◽  
Author(s):  
Dandan Zhu ◽  
Qiang Ye ◽  
Xuemin Lu ◽  
Qinghua Lu
Keyword(s):  
Ambient Temperature ◽  
High Surface ◽  
Side Chain ◽  
Side Chains ◽  
Self Healing ◽  
Adhesion Properties ◽  
Surface Energies

Copolymers with a PEG oligomer side chain present high surface energies and adhesion properties; they also can quickly self-heal the crack interfaces spontaneously at ambient temperature.

Natural Carbonation of Thermally Damaged Cement Mortar Studied by Thermogravimetric Analysis

2014 ◽  
Vol 529 ◽  
pp. 41-44
Author(s):  
Son Tung Pham ◽  
William Prince
Keyword(s):  
Heat Treatment ◽  
Calcium Carbonate ◽  
Thermogravimetric Analysis ◽  
Ambient Temperature ◽  
Cement Mortar ◽  
Self Healing ◽  
Healing Effect ◽  
Carbonation Process ◽  
Different Temperatures ◽  
Natural Carbonation

The objective of this study was to examine the natural carbonation that occurs during the cooling of thermally damaged cement mortar. Thermogravimetric analysis was used to follow mineralogical changes of CEM II mortar which was treated at different temperatures from 105 to 500°C. The results showed that, during the cooling to ambient temperature, by capturing CO2 from atmosphere the cement mortar tends to gain calcium carbonate from the loss of portlandite which was caused by heat treatment. This natural carbonation process allows the thermally damaged mortar to autonomously generate self-healing effect so that it can regain the initial properties.

scholarly journals Sustainable self-healing at ultra-low temperatures in structural composites incorporating hollow vessels and heating elements

2016 ◽  
Vol 3 (9) ◽  
pp. 160488 ◽  
Author(s):  
Yongjing Wang ◽  
Duc Truong Pham ◽  
Zhichun Zhang ◽  
Jinjun Li ◽  
Chunqian Ji ◽  
...  
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Low Temperatures ◽  
Three Dimensional ◽  
Natural World ◽  
The Other ◽  
Self Healing ◽  
Structural Composites ◽  
Healing Efficiency ◽  
Structural Composite

Self-healing composites are able to restore their properties automatically. Impressive healing efficiencies can be achieved when conditions are favourable. On the other hand, healing might not be possible under adverse circumstances such as very low ambient temperature. Here, we report a structural composite able to maintain its temperature to provide a sustainable self-healing capability—similar to that in the natural world where some animals keep a constant body temperature to allow enzymes to stay active. The composite embeds three-dimensional hollow vessels with the purpose of delivering and releasing healing agents, and a porous conductive element to provide heat internally to defrost and promote healing reactions. A healing efficiency over 100% at around −60°C was obtained. The effects of the sheets on the interlaminar and tensile properties have been investigated experimentally. The proposed technique can be implemented in a majority of extrinsic self-healing composites to enable automatic recovery at ultra-low temperatures.

scholarly journals Self-healing zwitterionic sulfobetaine nanocomposite hydrogels with good mechanical properties

RSC Advances ◽  
2019 ◽  
Vol 9 (55) ◽  
pp. 31806-31811 ◽  
Author(s):  
Yinlei Lin ◽  
Zheng Zeng ◽  
Yuhao Li ◽  
Sheng Sun ◽  
Xiaoting Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ambient Temperature ◽  
Self Healing ◽  
Nanocomposite Hydrogels

The prepared zwitterionic sulfobetaine nanocomposite hydrogels can autonomously repair incisions or cracks at ambient temperature without the need for any stimulus and possess excellent mechanical properties.

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Crystallographic Characterization of Dislocation Loops in Irradiated Tungsten

1968 ◽  
Vol 26 ◽  
pp. 290-291
Author(s):  
Robert C. Rau
Keyword(s):  
Electron Microscope ◽  
Ambient Temperature ◽  
Dislocation Loops ◽  
Polycrystalline Specimen ◽  
Post Irradiation ◽  
Neutron Fluences

Previous work has shown that post-irradiation annealing, at temperatures near 1100°C, produces resolvable dislocation loops in tungsten irradiated to fast (E > 1 MeV) neutron fluences of about 4 x 1019 n/cm2 or greater. To crystallographically characterize these loops, tilting experiments were carried out in the electron microscope on a polycrystalline specimen which had been irradiated to 1.5 × 1021 n/cm2 at reactor ambient temperature (∼ 70°C), and subseouently annealed for 315 hours at 1100°C. This treatment produced large loops averaging 1000 Å in diameter, as shown in the micrographs of Fig. 1. The orientation of this grain was near (001), and tilting was carried out about axes near [100], [10] and [110].

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

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