Influence of polydispersity on the phase behavior of colloidal liquid crystals: A Monte Carlo simulation study

Bates, Martin A.; Frenkel, Daan

doi:10.1063/1.477248

Cited by 139 publications

(140 citation statements)

References 16 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…Figure 3 gives a schematic overview of the typical modifications in the CNC production route and the surface chemistry of the final product. 41,42 and with the glass transition taking place at a somewhat higher concentration. It is instructive to compare the behavior of CNC suspensions at different concentrations with that of other rodshaped particle colloids.…”

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

View full text Add to dashboard Cite

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

show abstract

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

View full text Add to dashboard Cite

show abstract

“…Suspensions of fd rods in aqueous solution form several lyotropic liquid crystalline phases, in particular the chiral nematic (cholesteric) phase and the smectic phase [14]. The existence of a smectic phase in suspensions of hard rods is an evidence of the high monodispersity and therefore of the model system character of such filamentous viruses [15,16]. The colloidal scale of the fd bacteriophage facilitates the imaging of individual rods by fluorescence microscopy, as well as smectic layers by differential interference contrast (DIC) microscopy [14].…”

mentioning

confidence: 99%

Self-Diffusion of Rodlike Viruses through Smectic Layers

2007

View full text Add to dashboard Cite

We report the direct visualization at the scale of single particles of mass transport between smectic layers, also called permeation, in a suspension of rod-like viruses. Self-diffusion takes place preferentially in the direction normal to the smectic layers, and occurs by quasi-quantized steps of one rod length. The diffusion rate corresponds with the rate calculated from the diffusion in the nematic state with a lamellar periodic ordering potential that is obtained experimentally.Since the pioneering work of Onsager on the entropy driven phase transition to a liquid crystalline state [1], the structure and the phase behavior of complex fluids containing anisotropic particles with hard core interactions has been a subject of considerable interest, both theoretically [2] and experimentally [3]. Understanding of the particle mobility in the different liquid crystalline phases is more recent [4]. In experiments various methods have been applied to obtain the ensemble averaged selfdiffusion coefficients in thermotropic [5] and amphiphilic [6] liquid crystals, block copolymer [7] and colloidal systems [8]. Only a few studies have been done where dynamical phenomena are probed at the scale of a single anisotropic particle: the Brownian motion of an isolated colloidal ellipsoid in confined geometry [9] and the selfdiffusion in a nematic phase formed by rod-like viruses [10] represent two recent examples. In the latter case, the diffusion parallel (D ) and perpendicular (D ⊥ ) to the average rod orientation (the director) has been measured, showing an increase of the ratio D /D ⊥ with particle concentration. Knowledge of the dynamics at the single particle level is fundamental for understanding the physics of mesophases with spatial order like the smectic (lamellar) phase of rod-like particles. In this mesophase the particle density is periodic in one dimension parallel to the long axis of the rods, while the interparticle correlations perpendicular to this axis are short-ranged (fluid-like order). For parallel diffusion to take place, the rods need to jump between adjacent smectic layers, overcoming an energy barrier related to the smectic order parameter [11]. This process of interlayer diffusion, or permeation, was first predicted by Helfrich [12]. In this Letter, we use video fluorescence microscopy to monitor the dynamics of individual labeled colloidal rods in the background of a smectic mesophase formed by identical but unlabeled rods. In this way we directly observe permeation of single rods in adjacent layers. As in the nematic phase, self-diffusion in a smectic phase is anisotropic: the diffusion through the smectic layers is shown here to be much faster than the diffusion within each liquid-like layer, i.e. D /D ⊥ ≫ 1, in contrast to thermotropic systems. Moreover, since the individual rod positions within the layer are monitored, the potential barrier for permeation is straightly determined for the first time. The permeation can then be . The layer spacing is L ≃ 0.9 µm. (b) Displacement of a given particle...

show abstract

“…[54]). The influence of polydispersity -i. e., fluctuating rod length -on the phase diagram has been investigated by Bates et al [55]. Perhaps not surprisingly, the smectic phase is destabilized in favor of the nematic phase.…”

Section: Other Modelsmentioning

confidence: 99%