scholarly journals In-situ-grown silver–polymer framework with coordination complexes for functional artificial tissues

2021 ◽  
Author(s):  
Swee Ching Tan ◽  
Songlin Zhang ◽  
Yibing Deng ◽  
Alberto Libanori ◽  
Yihao Zhou ◽  
...  
Keyword(s):  
Coordination Complexes ◽  
Homogeneous Material ◽  
Multimodal Sensing ◽  
Dynamic Materials ◽  
Neuromuscular Systems ◽  
Polymer Framework ◽  
External Stimuli ◽  
Poor Adhesion ◽  
Metal Ligand

Abstract Sensorized actuators are critical to imitate proprio-/exteroception properties of biological neuromuscular systems. Existing add-on approaches, which physically blend heterogeneous sensor/actuator components, fall short of yielding satisfactory solutions, considering their suboptimal interfaces, poor adhesion, and electronic/mechanical property mismatch. Here, we report a single homogeneous material comprising seamless sensing-actuation unification properties at nano-/molecule levels, in which built-in sensing functions originate from the actuator architecture itself. In-situ-grown silver nanoparticles and metal-ligand complexes cooperatively create a silver–polymer framework (SPF) that is stretchable (1200%), conductive (0.076 S/m), and strong (0.76 MPa in-strength). SPF displays concomitant multimodal sensing (mechanical and thermal cues) and sensorized actuation capabilities, which include proprio-deformation and external stimuli perceptions (simultaneous with load-lifting ability up to 3700× of own weight). In view of its human somatosensitive muscular systems imitative functionality, the reported SPFs bode well for use with next generation functional tissues including artificial skins, human-machine interfaces, self-sensing robots, and otherwise dynamic materials.

scholarly journals Reversible Assembly of Terpyridine Incorporated Norbornene-Based Polymer via a Ring-Opening Metathesis Polymerization and Its Self-Healing Property

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1173 ◽  
Author(s):  
Jookyeong Lee ◽  
Hwi Moon ◽  
Keewook Paeng ◽  
Changsik Song
Keyword(s):  
Ring Opening ◽  
Transition Metal Ions ◽  
Self Healing ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Ligand Interactions ◽  
Healing Agent ◽  
Healing Property ◽  
External Stimuli ◽  
Metal Ligand

We induced a terpyridine moiety into a norbornene-based polymer to demonstrate its self-healing property, without an external stimulus, such as light, heat, or healing agent, using metal–ligand interactions. We synthesized terpyridine incorporated norbornene-based polymers using a ring-opening metathesis polymerization. The sol state of diluted polymer solutions was converted into supramolecular assembled gels, through the addition of transition metal ions (Ni2+, Co2+, Fe2+, and Zn2+). In particular, a supramolecular complex gel with Zn2+, which is a metal with a lower binding affinity, demonstrated fast self-healing properties, without any additional external stimuli, and its mechanical properties were completely recovered.

Retaining Alkyl Nucleophile Regiofidelity in Transition-Metal-Mediated Cross-Couplings to Aryl Electrophiles

Synthesis ◽  
2018 ◽  
Vol 50 (20) ◽  
pp. 3974-3996 ◽  
Author(s):  
Josep Cornella ◽  
Matthew O’Neill
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
Chemical Space ◽  
Cross Coupling ◽  
Transition Metal Catalysis ◽  
Metal Catalysis ◽  
Substantial Progress ◽  
Tertiary Alkyl ◽  
Metal Ligand

While the advent of transition-metal catalysis has undoubtedly transformed synthetic chemistry, problems persist with the introduction of secondary and tertiary alkyl nucleophiles into C(sp2) aryl electrophiles. Complications arise from the delicate organometallic intermediates typically invoked by such processes, from which competition between the desired reductive elimination event and the deleterious β-H elimination pathways can lead to undesired isomerization of the incoming nucleophile. Several methods have integrated distinct combinations of metal, ligand, nucleophile, and electrophile to provide solutions to this problem. Despite substantial progress, refinements to current protocols will facilitate the realization of complement reactivity and improved functional group tolerance. These issues have become more pronounced in the context of green chemistry and sustainable catalysis, as well as by the current necessity to develop robust, reliable cross-couplings beyond less explored C(sp2)–C(sp2) constructs. Indeed, the methods discussed herein and the elaborations thereof enable an ‘unlocking’ of accessible topologically enriched chemical space, which is envisioned to influence various domains of application.1 Introduction2 Mechanistic Considerations3 Magnesium Nucleophiles4 Zinc Nucleophiles5 Boron Nucleophiles6 Other Nucleophiles7 Tertiary Nucleophiles8 Reductive Cross-Coupling with in situ Organometallic Formation9 Conclusion

Well-Aligned In-situ Formed Open-End Carbon Nanotube for Device and Assembly Applications

2006 ◽  
Vol 968 ◽  
Author(s):  
Lingbo Zhu ◽  
ChingPing Wong
Keyword(s):  
Carbon Nanotube ◽  
Thermal Management ◽  
Field Enhancement ◽  
High Carbon ◽  
Electrical Interconnects ◽  
Emission Testing ◽  
Reaction Furnace ◽  
Poor Adhesion ◽  
Good Agreement

ABSTRACTCarbon nanotubes (CNTs) have been proposed for applications in microelectronic applications, especially for electrical interconnects, thermal management, and nanodevices, due to their excellent electrical, thermal, and mechanical properties. In this paper, we reported a simple process to achieve simultaneous CNT growth and opening of the CNT ends, while keeping alignment of the original CNT films/arrays. The addition of relatively low reactivity oxidizing agents (water) into the reaction furnace enables the feasibility. We proposed using novel CNT transfer technology, enabled by open-ended CNTs, to circumvent the high carbon nanotube (CNT) growth temperature and poor adhesion with the substrates that currently plague CNT implementation. The process is featured with separation of high-temperature CNT growth and low-temperature CNT device assembly. Field emission testing of the as-assembled CNT devices is in a good agreement with the Fowler-Nordheim (FN) equation, with a field enhancement factor of 4540.

Crystal structures, in situ synthesis in aqua conditions and luminescent properties of benzimidazole ligands and cadmium coordination complexes

2015 ◽  
Vol 435 ◽  
pp. 215-222 ◽  
Author(s):  
Yong-Cong Ou ◽  
Han-Cheng Chen ◽  
Yuan-Hao Liang ◽  
Jun-Jie Tang ◽  
Shao-Bin Feng ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Luminescent Properties ◽  
Coordination Complexes ◽  
In Situ Synthesis

scholarly journals A Soft On/Off Switch Based on the Electrochemically Reversible H-J Interconversion of a Floating Porphyrin Membrane

2021 ◽  
Author(s):  
Andrés F. Molina-Osorio ◽  
Sho Yamamoto ◽  
Alonso Gamero-Quijano ◽  
Hirohisa Nagatani ◽  
Micheal D. Scanlon
Keyword(s):  
Self Assembly ◽  
Electrical Potential ◽  
Electrolyte Solutions ◽  
Structural Rearrangement ◽  
Organic Electrolyte ◽  
Molecular Configuration ◽  
Additional Control ◽  
The Individual ◽  
External Stimuli

<p>Soft molecular assemblies that respond reversibly to external stimuli are attractive materials as on/off switches, in optoelectronic, memory and sensor technologies. In this article, we present the reversible structural rearrangement of a soft porphyrin membrane under an electrical potential stimulus in the absence of solid-state architectures. The free-floating porphyrin membrane lies at the interface between immiscible aqueous and organic electrolyte solutions and is formed through interfacial self-assembly of zinc(II) meso-tetrakis(4-carboxyphenyl)porphyrins (ZnPor). A potential difference between the two immiscible electrolyte solutions induces the intercalation of bis(triphenylphosphoranylidene)ammonium cations from the organic electrolyte that exchange with protons in the porphyrin membrane. In situ UV/vis absorbance spectroscopy shows that this ionic intercalation and exchange induces a structural interconversion of the individual porphyrin molecules in the membrane from an H- to a J-type molecular configuration. These structural rearrangements are reversible over 30 potential cycles. In situ polarisation-modulation fluorescence spectroscopy further provides clear evidence of structural interconversion of the porphyrin membrane, as intercalation of the organic electrolyte cations significantly affects the latter’s emissive properties. By adjusting the pH of the aqueous phase, additional control of the electrochemically reversible structural interconversion can be achieved, with total suppression at pH 3.<br></p>

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