The structure–property relationship in LAPONITE® materials: from Wigner glasses to strong self-healing hydrogels formed by non-covalent interactions

Soft Matter ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 1278-1289 ◽  
Author(s):  
Tiago B. Becher ◽  
Carolyne B. Braga ◽  
Diego L. Bertuzzi ◽  
Miguel D. Ramos ◽  
Ayaz Hassan ◽  
...  

Rheology, SAXS, and dynamic light scattering (DLS) analysis, zeta potential measurement, scanning electron microscopy (SEM), and micro-FTIR and absorbance spectroscopy were used to enlighten the controversial literature about LAPONITE® materials.

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Mingjie Ma ◽  
Guanyu Wang ◽  
Zhengpeng Yang ◽  
Shanxiu Huang ◽  
Weijie Guo ◽  
...  

Solid waste red mud was modified by HCl leaching. The structure property and composition of modified red mud were investigated by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Under UV irradiation, methyl orange (MO) aqueous solution was photodegraded by modified red mud. The obtained results showed that the specific surface area of modified red mud was 317.14 m2/g, which was about 40 times higher than that of the normal red mud. After UV irradiation for 50 min, the removal percentage of MO reached 94.2%. The study provided a novel way for the application of red mud to the photocatalytic degradation of organic wastes.


2013 ◽  
Vol 19 (S2) ◽  
pp. 1096-1097
Author(s):  
D. Abou-Ras ◽  
K. Tsyrulin ◽  
N. Schäfer ◽  
M. Nichterwitz ◽  
H. Kropf ◽  
...  

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.


2015 ◽  
Vol 90 (4) ◽  
pp. 581-584 ◽  
Author(s):  
Hiram Larangeira de Almeida Jr. ◽  
Henrique Isaacsson ◽  
Isabelle Maffei Guarenti ◽  
Ricardo Marques e Silva ◽  
Luis Antônio Suita de Castro

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Nafeesa Shaheen ◽  
Rao Arsalan Khushnood ◽  
Siraj Ud din

For preserving concrete structures and hindering ingress of chemicals through cracks and fissures, repair is inevitable. Microbial calcite precipitation is an intrinsic approach for crack rectification and emulating way of sustainability for reducing anthropogenic greenhouse gases (GHGs) along with conserving the natural resources. In this study,Bacillus subtilisstrain is applied for intrinsic repair of concrete’s cracks because of its high pH endurance and capability of sporulation. For prolonged survival of microorganisms, immobilization technique was employed.B. subtiliswas immobilized through limestone powder (LSP) before adding into cement matrix. Self-healing proficiency ofB. subtiliswas deliberated in terms of mechanical strength regain after cracking at 3, 7, 14, and 28 days. To examine the microstructure and characterization of healing precipitate, micrographical (field emission scanning electron microscopy), chemical (energy dispersive X-ray), and thermal (thermogravimetric analysis) analyses were performed after the healing period of 28 days. The results revealed evident signs of calcite precipitation in nano-/microcracks subsequent to microbial activity. Furthermore, immobilized LSP improved the compressive strength of the analyzed formulations.


2019 ◽  
Vol 28 (5) ◽  
pp. 348-355
Author(s):  
Young Joon Kwon ◽  
Jeevan Kumar Reddy Modigunta ◽  
AM Shanmugharaj ◽  
Hyung Jin Mun ◽  
Sung Hun Ryu

Self-healing polyurethane (SHPU) containing disulfide was synthesized and used as a binder to investigate its effect on the performance of reduced graphene oxide–tin oxide electrodes compared to those of polyurethane (PU) and poly(vinylidene difluoride) (PVDF) binders in Li-ion battery (LIB). Structural and morphological characterization of the SHPU and electrode was performed using a tensile tester, Fourier transform infrared spectroscopy, X-ray diffractometer, and scanning electron microscopy. Electrochemical performance was investigated using Galvanostatic charge–discharge and electrochemical impedance measurements. The tensile properties and scanning electron microscopy photographs confirmed the self-healing characteristics of the synthesized SHPU. Electrochemical studies were conducted using an RGO-SnO2 electrode. The electrochemical measurements revealed that the SnO2-pillared carbon-based anode materials with SHPU binder showed improved cycling performances with an excellent reversible capacity retention compared to PU or PVDF. After 1000 cycles at 1C, the surface morphology of the electrode with SHPU showed no cracks or dendrites, while the PVDF-based electrode possessed some cracks and dendrites on its surface. The electrochemical results confirmed that SHPU binder improves the electrochemical performance of LIBs.


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.


Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.


Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.


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