Highly Ordered Carbon Nanotube Nematic Liquid Crystals

Puech, Nicolas; Blanc, Christophe; Grelet, Éric; Zamora‐Ledezma, Camilo; Maugey, Maryse; Zakri, Cécile; Anglaret, Éric; Poulin, Philippe

doi:10.1021/jp1102077

Cited by 78 publications

(87 citation statements)

References 54 publications

(103 reference statements)

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“…Using the integrated absorptions over the measured absorption band from 450 to 700 nm results in a similar value of S = 0.74. The scalar order parameter measured here is slightly larger than the values measured for other systems of rod-like particles at coexistence [25][26][27][28].…”

Section: B Order Parameter and Optical Properties Of Nematic Phase Icontrasting

confidence: 78%

Experimental realization of crossover in shape and director field of nematic tactoids

et al. 2015

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Spindle-shaped nematic droplets (tactoids) form in solutions of rod-like molecules at the onset of the liquid crystalline phase. Their unique shape and internal structure result from the interplay of the elastic deformation of the nematic and anisotropic surface forces. The balance of these forces dictates that tactoids must display a continuous variation in aspect ratio and director-field configuration. Yet, such continuous transition has eluded observation for decades: tactoids have displayed either a bipolar configuration with particles aligned parallel to the droplet interface or a homogeneous configuration with particles aligned parallel to the long axis of the tactoid. Here, we report the first observation of the continuous transition in shape and director-field configuration of tactoids in true solutions of carbon nanotubes in chlorosulfonic acid. This observation is possible because the exceptional length of carbon nanotubes shifts the transition to a size range that can be visualized by optical microscopy. Polarization micrographs yield the interfacial and elastic properties of the system. Absorbance anisotropy measurements provide the highest nematic order parameter (S = 0.79) measured to date for a nematic phase of carbon nanotubes at coexistence with its isotropic phase.

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Section: B Order Parameter and Optical Properties Of Nematic Phase Icontrasting

confidence: 78%

Experimental realization of crossover in shape and director field of nematic tactoids

et al. 2015

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“…Thus, no other liquid crystal phase apart from the nematic phase has been reported thus far, [47][48][49][50] and a glass transition was reported only for very welldispersed carbon nanotubes at a very low threshold concentration. 32 The difficulty in observing higher-order liquid crystal phases with carbon nanotubes is also a result of the large size distribution of the tube length.…”

Section: Extraction Of Cncs From Biological Sourcesmentioning

confidence: 99%

Cellulose nanocrystal-based materials: from liquid crystal self-assembly and glass formation to multifunctional thin films

et al. 2014

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Cellulose nanocrystals (CNCs), produced by the acid hydrolysis of wood, cotton or other cellulose-rich sources, constitute a renewable nanosized raw material with a broad range of envisaged uses: for example, in composites, cosmetics and medical devices. The intriguing ability of CNCs to self-organize into a chiral nematic (cholesteric) liquid crystal phase with a helical arrangement has attracted significant interest, resulting in much research effort, as this arrangement gives dried CNC films a photonic band gap. The films thus acquire attractive optical properties, creating possibilities for use in applications such as security papers and mirrorless lasing. In this critical review, we discuss the sensitive balance between glass formation and liquid crystal self-assembly that governs the formation of the desired helical structure. We show that several as yet unclarified observations-some constituting severe obstacles for applications of CNCs-may result from competition between the two phenomena. Moreover, by comparison with the corresponding self-assembly processes of other rod-like nanoparticles, for example, carbon nanotubes and fd virus particles, we outline how further liquid crystal ordering phenomena may be expected from CNCs if the suspension parameters can be better controlled. Alternative interpretations of some unexpected phenomena are provided, and topics for future research are identified, as are new potential application strategies. NPG Asia Materials (2014) 6, e80; doi:10.1038/am.2013.69; published online 10 January 2014Keywords: cholesteric; gel; glass; liquid crystal; nanocellulose; photonic crystal; self-assembly INTRODUCTION Nanomaterials based on renewable resources are attracting rapidly growing interest, both from a fundamental scientific point of view and from the perspective of developing novel structural and functional macroscopic materials. 1,2 Using nature-based nanomaterials offers ecological advantages, and the extraordinary mechanical performance and/or photonic crystal character of biological composites such as bone, nacre, wood, beetle scales and butterfly wings is also an important inspiration for the development of new multifunctional materials. [3][4][5] However, full utilization of the intrinsic properties of nanosized starting materials requires the development of robust and versatile synthetic and processing routes to control assembly over several length scales. [6][7][8] Cellulose, one of the most versatile and widely found biopolymers in nature, has been used by humans for millennia as a building material, an energy source, a component of clothing and for storing and sharing knowledge and culture. Today, cellulose materials are used in a wide range of applications, and the paper and pulp industry

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“…Non-covalent functionalization is reversible or not, depending on the substances involved in the processes. The resulting mixtures give homogeneous dispersions [68], gels, and/or liquid crystalline materials [69][70][71][72][73]. The physical forces operating in such media compel the systems towards one possible state with respect to another.…”

Section: Discussionmentioning

confidence: 99%

Dispersability of Carbon Nanotubes in Biopolymer-Based Fluids

Tardani

Mesa

2015

Crystals

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Abstract:In this review the dispersability of carbon nanotubes in aqueous solutions containing proteins, or nucleic acids, is discussed. Data reported previously are complemented by unpublished ones. In the mentioned nanotube-based systems several different phases are observed, depending on the type and concentration of biopolymer, as well as the amount of dispersed nanotubes. The phase behavior depends on how much biopolymers are adsorbing, and, naturally, on the molecular details of the adsorbents. Proper modulation of nanotube/biopolymer interactions helps switching between repulsive and attractive regimes. Dispersion or phase separation take place, respectively, and the formation of liquid crystalline phases or gels may prevail with respect to dispersions. We report on systems containing ss-DNA-and lysozyme-stabilized nanotubes, representative of different organization modes. In the former case, ss-DNA rolls around CNTs and ensures complete coverage. Conversely, proteins randomly and non-cooperatively adsorb onto nanotubes. The two functionalization mechanisms are significantly different. A fine-tuning of temperature, added polymer, pH, and/or ionic strength conditions induces the formation of a given supra-molecular organization mode. The biopolymer physico-chemical properties are relevant to induce the formation of different phases made of carbon nanotubes.

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Highly Ordered Carbon Nanotube Nematic Liquid Crystals

Cited by 78 publications

References 54 publications

Experimental realization of crossover in shape and director field of nematic tactoids

Experimental realization of crossover in shape and director field of nematic tactoids

Cellulose nanocrystal-based materials: from liquid crystal self-assembly and glass formation to multifunctional thin films

Dispersability of Carbon Nanotubes in Biopolymer-Based Fluids

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