scholarly journals Retraction: Spatially resolved mechanical properties of photo-responsive azobenzene-based supramolecular gels

RSC Advances ◽  
2017 ◽  
Vol 7 (84) ◽  
pp. 53056-53056
Author(s):  
Gyuri Mun ◽  
Heekyoung Choi ◽  
Nayoung Im ◽  
Junho Ahn ◽  
Jaehyeon Park ◽  
...  

Retraction of ‘Spatially resolved mechanical properties of photo-responsive azobenzene-based supramolecular gels’ by Gyuri Mun et al., RSC Adv., 2017, 7, 26827–26833.

RSC Advances ◽  
2017 ◽  
Vol 7 (43) ◽  
pp. 26827-26833 ◽  
Author(s):  
Gyuri Mun ◽  
Heekyoung Choi ◽  
Nayoung Im ◽  
Junho Ahn ◽  
Jaehyeon Park ◽  
...  

The mechanical properties of azobenzene-based gelators were finely controlled by UV irradiation.


Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Emil Sandoz-Rosado ◽  
Michael R. Roenbeck ◽  
Kenneth E. Strawhecker

High-performance materials like ballistic fibers have remarkable mechanical properties owing to specific patterns of organization ranging from the molecular scale, to the micro scale and macro scale. Understanding these strategies for material organization is critical to improving the mechanical properties of these high-performance materials. In this work, atomic force microscopy (AFM) was used to detect changes in material composition at an extremely high resolution with transverse-stiffness scanning. New methods for direct quantification of material morphology were developed, and applied as an example to these AFM scans, although these methods can be applied to any spatially-resolved scans. These techniques were used to delineate between subtle morphological differences in commercial ultra-high-molecular-weight polyethylene (UHMWPE) fibers that have different processing conditions and mechanical properties as well as quantify morphology in commercial Kevlar®, a high-performance material with an entirely different organization strategy. Both frequency analysis and visual processing methods were used to systematically quantify the microstructure of the fiber samples in this study. These techniques are the first step in establishing structure-property relationships that can be used to inform synthesis and processing techniques to achieve desired morphologies, and thus superior mechanical performance.


Nanoscale ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 3275-3280 ◽  
Author(s):  
Ana M. Fuentes-Caparrós ◽  
Francisco de Paula Gómez-Franco ◽  
Bart Dietrich ◽  
Claire Wilson ◽  
Christopher Brasnett ◽  
...  

Annealing in a two-component supramolecular gel leads to a self-sorted network, which has significantly different mechanical properties to the as-prepared gels.


IAWA Journal ◽  
1997 ◽  
Vol 18 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Rupert Wimmer ◽  
Barry N. Lucas

Mechanical characterizations of the S2 layers and the cell corner middle lamella in the axial direction were investigated in spruce wood, A mechanical properties microprobe capable of measuring hardness and Young's modulus on a spatially resolved basis similar to that of an electron beam microprobe was used. Hardness of the cell comer middle lamella was found to be almost as high as that of the secondary wall, but the Young's modulus of the cell corner middle lamella was 50% less than that of the S2' The S2 showed constant hardness over its range of Young's modulus, but the cell corner middle lamella exhibited a strong correlation (R2 = 0.55) between hardness and the Young's modulus. Further investigations are needed to directly combine chemical and micromechanical properties and also to investigate the mechanical effects of the high variability of cell corner middle lamella chemistry.


2000 ◽  
Vol 649 ◽  
Author(s):  
M. Kunert ◽  
B. Baretzky ◽  
S. P. Baker ◽  
E. J. Mittemeijer

ABSTRACTThe variations of hardness, composition, and microstructure within a carbon implanted region – about 350 nm thick – of a Ti-6Al-4V alloy were measured using nanoindentation, Auger electron spectroscopy and transmission electron microscopy, respectively. Correlations among hardness, composition, and microstructure were made with a spatial resolution of about ±20 nm. The variation in hardness within the implanted regions was quantitatively explained as due to the formation of an almost continuous TiC layer and precipitate hardening. The problems that may arise in measuring and correlating spatial variations in such a complex material on this scale are outlined and a successful method to solve them is proposed. The need for highly spatially resolved measurement techniques is emphasized.


2018 ◽  
Vol 9 (28) ◽  
pp. 3900-3907 ◽  
Author(s):  
Jaehyeon Park ◽  
Ka Young Kim ◽  
Chaelin Kim ◽  
Ji Ha Lee ◽  
Ju Hyun Kim ◽  
...  

Supramolecular gels that possess high mechanical properties and unusual electrical conductivity were prepared by incorporating Cs+.


Author(s):  
Panjawat Kongsuwan ◽  
Hongliang Wang ◽  
Sinisa Vukelic ◽  
Y. Lawrence Yao

Femtosecond laser pulses were focused in the interior of a single fused silica piece. Proper use of optical and laser processing parameters generated structural rearrangement of the material through a thermal accumulation mechanism, which could be potentially used for the transmission welding process. The morphology of generated features was studied using differential interference contrast optical microscopy. In addition, the predictive capability of the morphology is developed via a finite element analysis. The change in mechanical properties was studied through employment of spatially resolved nanoindentation. The specimen was sectioned and nanoindents were applied at the cross section to examine mechanical responses of the laser-modified region. Fracture toughness measurements are carried out to investigate the effects of the laser treatment on strength of the glass.


2020 ◽  
Vol 34 (8) ◽  
pp. 1114-1130 ◽  
Author(s):  
Samand Pashneh-Tala ◽  
Robert Moorehead ◽  
Frederik Claeyssens

Poly(glycerol sebacate) is an attractive biomaterial for tissue engineering due to its biocompatibility, elasticity and rapid degradation rate. However, poly(glycerol sebacate) requires harsh processing conditions, involving high temperatures and vacuum for extended periods, to produce an insoluble polymer matrix. These conditions make generating accurate and intricate geometries from poly(glycerol sebacate), such as those required for tissue engineering scaffolds, difficult. Functionalising poly(glycerol sebacate) with methacrylate groups produces a photocurable polymer, poly(glycerol sebacate)-methacrylate, which can be rapidly crosslinked into an insoluble matrix. Capitalising on these improved processing capabilities, here, we present a variety of approaches for fabricating porous tissue engineering scaffolds from poly(glycerol sebacate)-methacrylate using sucrose porogen leaching combined with other manufacturing methods. Mould-based techniques were used to produce porous disk-shaped and tubular scaffolds. Porogen size was shown to influence scaffold porosity and mechanical performance, and the porous poly(glycerol sebacate)-methacrylate scaffolds supported the proliferation of primary fibroblasts in vitro. Additionally, scaffolds with spatially variable mechanical properties were generated by combining variants of poly(glycerol sebacate)-methacrylate with different stiffness. Finally, subtractive and additive manufacturing methods were developed with the capabilities to generate porous poly(glycerol sebacate)-methacrylate scaffolds from digital designs. These hybrid manufacturing strategies offer the ability to produce accurate macroscale poly(glycerol sebacate)-methacrylate scaffolds with tailored microscale porosity and spatially resolved mechanical properties suitable for a broad range of applications across tissue engineering.


1991 ◽  
Vol 239 ◽  
Author(s):  
B. N. Lucas ◽  
W. C. Oliver

ABSTRACTUsing a highly spatially resolved mechanical properties microprobe, the elastic, plastic and time dependent mechanical properties of sapphire and a 1.9 μm amorphous alumina film on a sapphire substrate have been studied. Young's modulus, hardness, and stress-exponent data are reported. The technique for characterizing time dependent properties via indentation (hardness versus displacement rate/displacement) are directly compared to standard uniaxial compressive techniques (stress vs strain rate) for a bulk Pb-In alloy to further quantify the relationships between the two techniques.


1991 ◽  
Vol 6 (12) ◽  
pp. 2519-2522 ◽  
Author(s):  
B.N. Lucas ◽  
W.C. Oliver ◽  
R.K. Williams ◽  
J. Brynestad ◽  
M.E. O'Hern

Using a highly-spatially-resolved mechanical properties microprobe, the Young's modulus and hardness of bulk YBa2Cu3O7−x (1:2:3) and YBa2Cu4O8 (1:2:4) have been determined. The Young's modulus of a superconductor is an important parameter in determining critical grain sizes above which microcracking will occur due to anisotropic thermal stresses that arise during processing. This phenomenon of microcracking has been determined to cause a decrease in the attainable critical current densities in bulk superconductors. The mechanical properties data for these two materials show that the Young's modulus of 1:2:3 is approximately 35% greater than the modulus of 1:2:4. This along with available anisotropic thermal expansion data for 1:2:3 and 1:2:4 suggests that the critical grain size for 1:2:4 is about 7 times greater than the critical grain size for microcracking in 1:2:3.


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