Defect trajectories in nematic shells: Role of elastic anisotropy and thickness heterogeneity

Seč, David; López-León, Teresa; Nobili, Maurizio; Blanc, Christophe; Fernández‐Nieves, Alberto; Ravnik, Miha; Žumer, S.

doi:10.1103/physreve.86.020705

Cited by 55 publications

(45 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…figure 4b), eventually distributing on a great circle, as initially shown by computer simulations by Shin et al [24]. Recent simulations suggest that the defect motion can be attributed primarily to the increasing elastic anisotropy as the smectic phase is approached [25].…”

Section: N-sma Transition In Shells With Planar and Hybrid Boundary Csupporting

confidence: 59%

Tuning the defect configurations in nematic and smectic liquid crystalline shells

Liang

Noh

Zentel

et al. 2013

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

Thin liquid crystalline shells surrounding and surrounded by aqueous phases can be conveniently produced using a nested capillary microfluidic system, as was first demonstrated by Fernandez-Nieves et al. in 2007. By choosing particular combinations of stabilizers in the internal and external phases, different types of alignment, uniform or hybrid, can be ensured within the shell. Here, we investigate shells in the nematic and smectic phases under varying boundary conditions, focusing in particular on textural transformations during phase transitions, on the interaction between topological defects in the director field and inclusions in the liquid crystal (LC), and on the possibility to relocate defects within the shell by rotating the shell in the gravitational field. We demonstrate that inclusions in a shell can seed defects that cannot form in a pristine shell, adding a further means of tuning the defect configuration, and that shells in which the internal aqueous phase is not density matched with the LC will gently rearrange the internal structure upon a rotation that changes the influence of gravity. Because the defects can act as anchor points for added linker molecules, allowing self-assembly of adjacent shells, the various arrangements of defects developing in these shells and the possibility of tuning the result by modifying boundary conditions, LC phase, thickness and diameter of the shell or applying external forces make this new LC configuration very attractive.

show abstract

Section: N-sma Transition In Shells With Planar and Hybrid Boundary Csupporting

confidence: 59%

Tuning the defect configurations in nematic and smectic liquid crystalline shells

Liang

Noh

Zentel

et al. 2013

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

show abstract

“…Most of these works were mainly focusing on spherical nematic shells with four defects with a charge of one-half. Experimental investigations on nematic shells generated by trapping a water droplet inside a nematic droplet, however, have revealed the existence of a much wider variety of defect * koning@lorentz.leidenuniv.nl structures besides the regular tetrahedral defect arrangement [6,12,18,21,[31][32][33], even with a valence number different from four [6,12,21]. There exist divalent configurations in which instead of four one-half defect lines spanning the shell, there are two pairs of point defects, called boojums, residing on the bounding surfaces.…”

Section: Introductionmentioning

confidence: 99%

Spherical nematic shells with a threefold valence

et al. 2016

Self Cite

View full text Add to dashboard Cite

We present a theoretical study of the energetics of thin nematic shells with two charge-one-half defects and one charge-one defect. We determine the optimal arrangement: the defects are located on a great circle at the vertices of an isosceles triangle with angles of 66• at the charge-one-half defects and a distinct angle of 48• , consistent with experimental findings. We also analyze thermal fluctuations around this ground state and estimate the energy as a function of thickness. We find that the energy of the three-defect shell is close to the energy of other known configurations having two charge-one and four charge-one-half defects. This finding, together with the large energy barriers separating one configuration from the others, explains their observation in experiments as well as their long-time stability.

show abstract

“…Note that, in real configurations, elastic anisotropies [26][27][28] of relevant elastic constants and extrinsic [2,3,[29][30][31] geometric terms might play an important role in the positioning of TDs. In our modelling, we considered only the so-called intrinsic free energy curvature terms.…”

Section: Discussionmentioning

confidence: 99%

“…A possible future application based on such systems might be scaled crystals [15,[25][26][27][28]. Namely, different configurations of TDs on ordered shells, immersed in an isotropic host, are expected to nucleate self-assembling into periodic structures exhibiting different symmetries and, consequently, quantitatively or even qualitatively different physical properties [15].…”

Section: Discussionmentioning

confidence: 99%

Curvature-Controlled Topological Defects

et al. 2017

View full text Add to dashboard Cite

Effectively, two-dimensional (2D) closed films exhibiting in-plane orientational ordering (ordered shells) might be instrumental for the realization of scaled crystals. In them, ordered shells are expected to play the role of atoms. Furthermore, topological defects (TDs) within them would determine their valence. Namely, bonding among shells within an isotropic liquid matrix could be established via appropriate nano-binders (i.e., linkers) which tend to be attached to the cores of TDs exploiting the defect core replacement mechanism. Consequently, by varying configurations of TDs one could nucleate growth of scaled crystals displaying different symmetries. For this purpose, it is of interest to develop a simple and robust mechanism via which one could control the position and number of TDs in such atoms. In this paper, we use a minimal mesoscopic model, where variational parameters are the 2D curvature tensor and the 2D orientational tensor order parameter. We demonstrate numerically the efficiency of the effective topological defect cancellation mechanism to predict positional assembling of TDs in ordered films characterized by spatially nonhomogeneous Gaussian curvature. Furthermore, we show how one could efficiently switch among qualitatively different structures by using a relative volume v of ordered shells, which represents a relatively simple naturally accessible control parameter.

show abstract

Defect trajectories in nematic shells: Role of elastic anisotropy and thickness heterogeneity

Cited by 55 publications

References 19 publications

Tuning the defect configurations in nematic and smectic liquid crystalline shells

Tuning the defect configurations in nematic and smectic liquid crystalline shells

Spherical nematic shells with a threefold valence

Curvature-Controlled Topological Defects

Contact Info

Product

Resources

About