Imaging studies of temperature dependent photodegradation and self-healing in disperse orange 11 dye-doped polymers

2016 ◽  
Vol 145 (2) ◽  
pp. 024901 ◽  
Author(s):  
Benjamin R. Anderson ◽  
Sheng-Ting Hung ◽  
Mark G. Kuzyk
Keyword(s):  
Self Healing ◽  
Imaging Studies ◽  
Temperature Dependent ◽  
Doped Polymers

scholarly journals Imaging studies of photodamage and self-healing in disperse orange 11 dye-doped PMMA

2011 ◽  
Vol 28 (3) ◽  
pp. 528 ◽  
Author(s):  
Benjamin Anderson ◽  
Shiva K. Ramini ◽  
Mark G. Kuzyk
Keyword(s):  
Self Healing ◽  
Imaging Studies

scholarly journals Analysis of Fatigue and Healing Properties of Conventional Bitumen and Bio-Binder for Road Pavements

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 420 ◽  
Author(s):  
Elena Gaudenzi ◽  
Fabrizio Cardone ◽  
Xiaohu Lu ◽  
Francesco Canestrari
Keyword(s):  
Experimental Approach ◽  
Fatigue Behavior ◽  
Self Healing ◽  
Aged Condition ◽  
Temperature Dependent ◽  
Modified Bitumen ◽  
Complex Issue ◽  
Rheological Measurements ◽  
Bio Oil ◽  
Bituminous Binders

The analysis of fatigue behavior of bituminous binders is a complex issue due to several time-temperature dependent phenomena which interact simultaneously, such as damage accumulation, viscoelasticity, thixotropy, and healing. The present research involves rheological measurements aimed at evaluating the fatigue behavior and compares the self-healing capability of two plain bitumen and a bio-binder obtained by partially replacing one of the plain bitumen with a renewable bio-oil. Healing potential was assessed by means of an experimental approach previously implemented for modified bitumen and bituminous mastic and based on the use of a dynamic shear rheometer (DSR). The effects of some variables such as bitumen type, bio-oil addition, and aging on the healing potential of binders were taken into account. Results showed that the above-mentioned method for healing analysis is also suitable for conventional and bio-add binders. Outcomes of the experimental investigation highlight that fatigue and self-healing are mainly dependent on binder consistency and also affected by aging. Finally, the addition of bio-oil may induce even better performances in terms of healing potential compared to conventional bitumen, especially in aged condition.

scholarly journals Supramolecular Dimerization in a Polymer Melt from Small-Angle X-ray Scattering and Rheology: A Miscible Model System

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 880
Author(s):  
Mariapaola Staropoli ◽  
Margarita Kruteva ◽  
Jürgen Allgaier ◽  
Andreas Wischnewski ◽  
Wim Pyckhout-Hintzen
Keyword(s):  
Hydrogen Bonding ◽  
Small Angle ◽  
Full Range ◽  
Polymer Melt ◽  
Self Healing ◽  
Temperature Dependent ◽  
Base Pairs ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

We present a structural and dynamic study on the simplest supramolecular hetero-association, recently investigated by the authors to prepare architectural homogeneous structures in the melt state, based on the bio-inspired hydrogen-bonding of thymine/diaminotriazine (thy–DAT) base-pairs. In the combination with an amorphous low Tg poly(butylene oxide) (PBO), no micellar structures are formed, which is expected for nonpolar polymers because of noncompatibility with the highly polar supramolecular groups. Instead, a clear polymer-like transient architecture is retrieved. This makes the heterocomplementary thy–DAT association an ideal candidate for further exploitation of the hydrogen-bonding ability in the bulk for self-healing purposes, damage management in rubbers or even the development of easily processable branched polymers with built-in plasticizer. In the present work, we investigate the temperature range from Tg + 20 °C to Tg + 150 °C of an oligomeric PBO using small-angle X-ray scattering (SAXS) and linear rheology on the pure thy and pure DAT monofunctionals and on an equimolar mixture of thy/DAT oligomers. The linear rheology performed at low temperature is found to correspond to fully closed-state dimeric configurations. At intermediate temperatures, SAXS probes the equilibrium between open and closed states of the thy–DAT mixtures. The temperature-dependent association constant in the full range between open and closed H-bonds and an enhancement of the monomeric friction coefficient due to the groups is obtained. The thy–DAT association in the melt is more stable than the DAT–DAT, whereas the thy–thy association seems to involve additional long-lived interactions.

Imaging studies of photodegradation and self-healing in anthraquinone derivative dye-doped PMMA

2020 ◽  
Vol 22 (48) ◽  
pp. 28154-28164
Author(s):  
Benjamin R. Anderson ◽  
Mark G. Kuzyk
Keyword(s):  
Self Healing ◽  
Imaging Studies ◽  
Anthraquinone Derivative ◽  
Transmission Imaging ◽  
Anthraquinone Derivatives ◽  
Rules Of Thumb ◽  
Enhanced Photostability

We compare the photodegradation and self-healing properties of nine anthraquinone derivatives doped into PMMA using transmission imaging. The results suggests “rules-of-thumb” to predict enhanced photostability and self-healing for anthraquinones.

scholarly journals Imaging current distribution in a topological insulator Bi2Se3 in the presence of competing surface and bulk contributions to conductivity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amit Jash ◽  
Ankit Kumar ◽  
Sayantan Ghosh ◽  
A. Bharathi ◽  
S. S. Banerjee
Keyword(s):  
Thin Films ◽  
Topological Insulator ◽  
Current Distribution ◽  
Current Density ◽  
Current Flow ◽  
Bulk Conductivity ◽  
Imaging Studies ◽  
Temperature Dependent ◽  
Edge Current ◽  
Sheet Current

AbstractTwo-dimensional (2D) topological surface states in a three-dimensional topological insulator (TI) should produce uniform 2D surface current distribution. However, our transport current imaging studies on Bi2Se3 thin film reveal non-uniform current sheet flow at 15 K with strong edge current flow. This is consistent with other imaging studies on thin films of Bi2Se3. In contrast to strong edge current flow in thin films, in single crystal of Bi2Se3 at 15 K our current imaging studies show the presence of 3.6 nm thick uniform 2D sheet current flow. Above 70 K, this uniform 2D sheet current sheet begins to disintegrate into a spatially non-uniform flow. The flow becomes patchy with regions having high and low current density. The area fraction of the patches with high current density rapidly decreases at temperatures above 70 K, with a temperature dependence of the form $$1/\left| {T - 70} \right|^{0.35}$$ 1 / T - 70 0.35 . The temperature scale of 70 K coincides with the onset of bulk conductivity in the crystal due to electron doping by selenium vacancy clusters in Bi2Se3. Thus our results show a temperature dependent competition between surface and bulk conductivity produces a temperature dependent variation in uniformity of current flow in the topological insulator.

scholarly journals Imaging current distribution in a topological insulator Bi2Se3 in the presence of competing surface and bulk contributions to conductivity

2021 ◽  
Author(s):  
Amit Jash ◽  
Ankit Kumar ◽  
Sayantan Ghosh ◽  
A. Bharathi ◽  
S. Banerjee
Keyword(s):  
Thin Films ◽  
Topological Insulator ◽  
Current Distribution ◽  
Current Density ◽  
Current Flow ◽  
Bulk Conductivity ◽  
Imaging Studies ◽  
Temperature Dependent ◽  
Edge Current ◽  
Sheet Current

Abstract Two-dimensional (2D) topological surface states in a three-dimensional topological insulator (TI) should produce uniform 2D surface current distribution. However, our transport current imaging studies on Bi2Se3 thin film reveal non-uniform current sheet flow at 15 K with strong edge current flow. This is consistent with other imaging studies on thin films of Bi2Se3. In contrast to strong edge current flow in thin films, in single crystal of Bi2Se3 at 15 K our current imaging studies show the presence of 3.6 nm thick uniform 2D sheet current flow. Above 70 K, this uniform 2D sheet current sheet begins to disintegrate into a spatially non-uniform flow. The flow becomes patchy with regions having high and low current density. The area fraction of the patches with high current density rapidly decreases at temperatures above 70 K, with a temperature dependence of the form 1/|T-70| 0.35. The temperature scale of 70 K coincides with the onset of bulk conductivity in the crystal due to electron doping by selenium vacancy clusters in Bi2Se3. Thus our results show a temperature dependent competition between surface and bulk conductivity produces a temperature dependent variation in uniformity of current flow in the topological insulator.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Autonomous self-healing polyisoprene elastomers with high modulus and good toughness based on the synergy of dynamic ionic crosslinks and highly disordered crystals

2020 ◽  
Vol 11 (41) ◽  
pp. 6549-6558
Author(s):  
Yohei Miwa ◽  
Mayu Yamada ◽  
Yu Shinke ◽  
Shoichi Kutsumizu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Self Healing ◽  
High Modulus ◽  
Disordered Crystals ◽  
Ionic Crosslinks

We designed a novel polyisoprene elastomer with high mechanical properties and autonomous self-healing capability at room temperature facilitated by the coexistence of dynamic ionic crosslinks and crystalline components that slowly reassembled.

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