Hydration-Responsive Folding and Unfolding in Graphene Oxide Liquid Crystal Phases

Guo, Fei; Kim, Franklin; Han, Tae Hee; Shenoy, Vivek B.; Huang, Jiaxing; Hurt, Robert H.

doi:10.1021/nn2025644

Cited by 208 publications

(200 citation statements)

References 30 publications

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“…32,33 The latter may contribute to up to about 30% in weight of the mass detected, which thus includes both the actual GO mass and the water associated with it. 34 According to a Langmuir-type mechanism (Figure 2b The calculated average thickness increases from a minimum of 1 nm to a maximum of 11 nm as a function of GO bulk concentration (Figure 2b, black curve). Similarly to above, an increase in thickness can be correlated to hydration effects and sheet wrinkling on the AgNCs surface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Banchelli

Tiribilli

Angelis

et al. 2016

ACS Appl. Mater. Interfaces

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Hybrid graphene oxide (GO)/metal nanocomposites have been recently proposed as novel surface-enhanced Raman scattering (SERS) substrates. Despite an increasing interest in these systems, standardization in their fabrication process is still lacking but urgently required to support their use for real-life applications. In this work we investigate how the assembly of GO should be conducted to control adsorption geometry and optical properties at the interface with plasmonic nanostructures as monolayer assemblies of silver nanocubes, by tuning main experimental parameters including GO concentration and self-assembly time. We finally identified the experimental conditions for building up a close-fitting soft dressing of the plasmonic surface, which shows optimal characteristics for flexible and reliable SERS detection. KEYWORDS: plasmonic nanoparticles, sensing, self-assembly, Raman spectroscopy, quartz crystal microbalance ■ INTRODUCTIONSurface-enhanced Raman scattering (SERS) spectroscopy is as a robust and versatile analytical technique with the ability to offer detailed and label-free chemical information with molecular selectivity and ultrasensitivity. 1−5 The SERS effect relies on huge electromagnetic fields concentrated at the metal surface of a plasmonic nanostructure, which dramatically enhance the Raman signal of molecules placed in its close proximity. In this respect, efficient SERS enhancements are typically generated within less than 10 nm from the metal surface and are mostly confined within the so-called "hot spots", i.e. highly curved nanoregions or gaps and junctions between adjacent nanoparticles. The ability to gather molecules in these regions in a homogeneous and reproducible manner represents a current impediment that is still preventing further diffusion of SERS as a systematic analytical tool.A recent trend toward upgrading the performance of SERS technology relies on the combination of plasmonic nanostructures made of silver and gold with graphene. 6−9 Graphene is a single-atom-thick sheet of sp 2 -hybridized carbon atoms arranged in a honeycomb lattice. A number of unique chemical, electronic, optical, and structural properties make this material a preferred choice for greatly improving electronic and photonic devices. 10,11 With a focus on SERS, current efforts are taking advantage of a thin graphene coating in drawing and concentrating target molecules as well as in conferring the plasmonic surface with a passivating layer that discards possible disturbances and signal variability induced by metal−molecule interactions. 12 Main fabrication methods of graphene sheets include mechanical peel-off, epitaxial growth, and chemical vapor deposition (CVD), which, however, appear unsuitable for large-scale production of graphene, ultimately limiting its practical application. A convenient alternative is now represented by graphene oxide (GO), which is derived by oxidation of graphite in the form of graphene sheets with abundant oxygen-containing functionalities. These confer chemical st...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Banchelli

Tiribilli

Angelis

et al. 2016

ACS Appl. Mater. Interfaces

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“…[4] In this context, the recent discovery of liquid crystalline (LC) behavior of graphene oxide (GO) dispersions in various organic, [8] and aqueous media brings added control to the assembly of larger structures using the chemical process approach. [10][11][12][13][14][15][16] The LC state can be used to direct the ordered assembly of nanocomponents in macroscopic structures via simple methods like wet-spinning. [14,17] The orientation induced by the anisotropic phase combined with the additional contribution of the flow field in fiber spinning methods provide a viable approach to the creation of highly ordered domains and results in strong fibers without the need for post-spinning drawing treatments.…”

Section: Introductionmentioning

confidence: 99%

Scalable One‐Step Wet‐Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles

Jalili

Aboutalebi

Esrafilzadeh

et al. 2013

Adv Funct Materials

379

426

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. (2013). Scalable one-step wet-spinning of graphene fibers and yarns from liquid crystalline dispersions of graphene oxide: towards multifunctional textiles. Advanced Functional Materials, 23 (43), 5345-5354.Scalable one-step wet-spinning of graphene fibers and yarns from liquid crystalline dispersions of graphene oxide: towards multifunctional textiles AbstractKey points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micrometer-dimensional fibers and yarns are addressed. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability is proposed, leading to an understanding of lyotropic LC behavior and fiber spinnability. The knowledge gained from the straightforward formulation of LC GO "inks" in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating the need for relatively concentrated spinning dope dispersions. The dilute LC GO dispersion is proven to be suitable for fiber spinning using a number of coagulation strategies, including non-solvent precipitation, dispersion destabilization, ionic cross-linking, and polyelectrolyte complexation. One-step continuous spinning of graphene fibers and yarns is introduced for the first time by in situ spinning of LC GO in basic coagulation baths (i.e., NaOH or KOH), eliminating the need for post-treatment processes. The thermal conductivity of these graphene fibers is found to be much higher than polycrystalline graphite and other types of 3D carbon based materials. New insights are provided into the processing of liquid crystalline graphene oxide (GO) dispersion (containing large GO sheets) demonstrating a facile and scalable production of GO and reduced GO fibers and yarns with exciting properties such as high thermal conductivity. These results provide a universal platform for the development of solution-based processing methods, properties, and applications of liquid crystalline GO-based architectures. AbstractIn the present work, we address key points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micron dimensional fibers and yarns. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity and spinnability is proposed leading to the understanding of 2 lyotropic LC behavior and fiber spinnability. The knowledge gained from our straightforward formulation of LC GO "inks" in a range of processable concentrations enabled us to spin continuous conducting, strong and robust fibres at concentrations as low as 0.075 wt. % eliminating the need for relatively concentrated spinning dope dispersions. This concentration is the lowest ever rep...

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“…[1][2][3][4][5][6][7][8] The pursuit and development of novel, emerging functional materials provides rich opportunities for the design and construction of task-specific actuators. Additionally, driven by the desire for material sustainability, it is a tendency to fabricate actuators at least partially from biopolymers or bio-templates.…”

Section: Introductionmentioning

confidence: 99%

From Filter Paper to Functional Actuator by Poly(Ionic Liquid)‐Modified Graphene Oxide

Song

Lin

Antonietti

et al. 2016

Adv Materials Inter

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A commercially available membrane filter paper composed of mixed cellulose esters bearing typically an interconnected pore structure was transformed into a stimuli-responsive bilayer actuator by depositing a thin film of poly(ionic liquid)-modified graphene oxide sheets (GO-PIL) onto the filter paper. In acetone vapor, the as-synthesized bilayer actuator bent readily into multiple loops at a fast speed with the GO-PIL top film inwards. Upon pulling back into air the actuator recovered their original shape. The asymmetric swelling of the top GO-PIL film and the bottom porous filter paper towards organic vapor offers a favorably synergetic function to drive the actuation. The PIL polymer chains in the hybrid film were proven crucial to enhance the adhesion strength between the GO sheets and the adjacent filter paper to avoid interfacial delamination and thus improve force transfer. The overall construction allows a prolonged lifetime of the bilayer actuator under constant operation, especially when compared to that of the GO/filter paper bilayer actuator without PIL.2

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Hydration-Responsive Folding and Unfolding in Graphene Oxide Liquid Crystal Phases

Cited by 208 publications

References 30 publications

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Scalable One‐Step Wet‐Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles

From Filter Paper to Functional Actuator by Poly(Ionic Liquid)‐Modified Graphene Oxide

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