scholarly journals Transformation between elastic dipoles, quadrupoles, octupoles, and hexadecapoles driven by surfactant self-assembly in nematic emulsion

2021 ◽  
Vol 7 (25) ◽  
pp. eabg0377
Author(s):  
Bohdan Senyuk ◽  
Ali Mozaffari ◽  
Kevin Crust ◽  
Rui Zhang ◽  
Juan J. de Pablo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Molecular Alignment ◽  
Smart Windows ◽  
Equilibrium Dynamics ◽  
Fundamental Science ◽  
Pair Interactions ◽  
Isotropic Fluid

Emulsions comprising isotropic fluid drops within a nematic host are of interest for applications ranging from biodetection to smart windows, which rely on changes of molecular alignment structures around the drops in response to chemical, thermal, electric, and other stimuli. We show that absorption or desorption of trace amounts of common surfactants can drive continuous transformations of elastic multipoles induced by the droplets within the uniformly aligned nematic host. Out-of-equilibrium dynamics of director structures emerge from a controlled self-assembly or desorption of different surfactants at the drop-nematic interfaces, with ensuing forward and reverse transformations between elastic dipoles, quadrupoles, octupoles, and hexadecapoles. We characterize intertransformations of droplet-induced surface and bulk defects, probe elastic pair interactions, and discuss emergent prospects for fundamental science and applications of the reconfigurable nematic emulsions.

scholarly journals Soft channel formation and symmetry breaking in exotic active emulsions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
L. N. Carenza ◽  
G. Gonnella ◽  
A. Lamura ◽  
D. Marenduzzo ◽  
G. Negro ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Self Assembly ◽  
Contractile Activity ◽  
Active Material ◽  
Fluid Flows ◽  
Shear Rates ◽  
Two Phases ◽  
The Stability ◽  
Isotropic Fluid

Abstract We use computer simulations to study the morphology and rheological properties of a bidimensional emulsion resulting from a mixture of a passive isotropic fluid and an active contractile polar gel, in the presence of a surfactant that favours the emulsification of the two phases. By varying the intensity of the contractile activity and of an externally imposed shear flow, we find three possible morphologies. For low shear rates, a simple lamellar state is obtained. For intermediate activity and shear rate, an asymmetric state emerges, which is characterized by shear and concentration banding at the polar/isotropic interface. A further increment in the active forcing leads to the self-assembly of a soft channel where an isotropic fluid flows between two layers of active material. We characterize the stability of this state by performing a dynamical test varying the intensity of the active forcing and shear rate. Finally, we address the rheological properties of the system by measuring the effective shear viscosity, finding that this increases as active forcing is increased—so that the fluid thickens with activity.

Fabrication of molecular alignment at the specific sites on Cu(111) surfaces using self-assembly phenomena

2000 ◽  
Vol 445 (1) ◽  
pp. L58-L63 ◽  
Author(s):  
Masashi Furukawa ◽  
Hiroyuki Tanaka ◽  
Ken-ichi Sugiura ◽  
Yoshiteru Sakata ◽  
Tomoji Kawai
Keyword(s):  
Self Assembly ◽  
Molecular Alignment

Non-Equilibrium Dynamics of Vesicles and Micelles by Self-Assembly of Block Copolymers with Double Thermoresponsivity

2016 ◽  
Vol 49 (7) ◽  
pp. 2895-2903 ◽  
Author(s):  
Yu-Hang Tang ◽  
Zhen Li ◽  
Xuejin Li ◽  
Mingge Deng ◽  
George Em Karniadakis
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Equilibrium Dynamics ◽  
Non Equilibrium

scholarly journals Stretchable and Hydrophobic Electrochromic Devices Using Wrinkled Graphene and PEDOT:PSS

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Srinivasa Kartik Nemani ◽  
Dayong Chen ◽  
Marwan H. Mohamed ◽  
Hossein Sojoudi
Keyword(s):  
Self Assembly ◽  
Graphene Film ◽  
Electrochromic Device ◽  
Color Contrast ◽  
Water Contact ◽  
Smart Windows ◽  
Wide Range ◽  
Average Water ◽  
Materials Used ◽  
New Generation

We present an electrochromic device (ECD) fabricated using PEDOT:PSS and graphene as active conductive electrode films and a flexible compliant polyurethane substrate with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TSFI) additive, as ionic medium. This device with a docile, elastic intermediate substrate along with a transparency controlled PEDOT:PSS film provides a wide color contrast and fast switching rate. We harness wrinkling instability of graphene to achieve a hydrophobic nature without compromising transparency of the ECD. This mechanical self-assembly approach helps in controlling the wavelength of wrinkles generated by inducing measured prestrain conditions and regulating the modulus contrast by selection of underlying materials used, hereby controlling the extent of transparency. The reduction and oxidation switching times for the device were analyzed to be 5.76 s and 5.34 s for a 90% transmittance change at an operating DC voltage of 15 ± 0.1 V. Strain dependent studies show that the performance was robust with the device retaining switching contrasts even at 15% uniaxial strain conditions. Our device also exhibits superior antiwetting properties with an average water contact angle of 110°  ± 2° at an induced radial prestrain of 30% in the graphene film. A wide range color contrast, flexibility, and antiwetting nature of the device envision its uses in smart windows, visors, and other wearable equipment where these functionalities are of outmost importance for developing new generation of smart interactive devices.

scholarly journals Hydrothermal growth of VO2 nanoplate thermochromic films on glass with high visible transmittance

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jiasong Zhang ◽  
Jingbo Li ◽  
Pengwan Chen ◽  
Fida Rehman ◽  
Yijie Jiang ◽  
...  
Keyword(s):  
Visible Light ◽  
Self Assembly ◽  
Vanadium Dioxide ◽  
Hydrothermal Process ◽  
Light Transmittance ◽  
Promising Technique ◽  
Smart Windows ◽  
Visible Transmittance ◽  
Thermochromic Properties ◽  
Facile Hydrothermal Process

Abstract The preparation of thermochromic vanadium dioxide (VO2) films in an economical way is of interest to realizing the application of smart windows. Here, we reported a successful preparation of self-assembly VO2 nanoplate films on TiO2-buffered glass by a facile hydrothermal process. The VO2 films composed of triangle-shaped plates standing on substrates exhibit a self-generated porous structure, which favors the transmission of solar light. The porosity of films is easily controlled by changing the concentration of precursor solutions. Excellent thermochromic properties are observed with visible light transmittance as high as 70.3% and solar modulating efficiency up to 9.3% in a VO2 film with porosity of ~35.9%. This work demonstrates a promising technique to promote the commercial utilization of VO2 in smart windows.

scholarly journals Anisotropic electrostatic screening of charged colloids in nematic solvents

2021 ◽  
Vol 7 (5) ◽  
pp. eabd0662
Author(s):  
Jeffrey C. Everts ◽  
Bohdan Senyuk ◽  
Haridas Mundoor ◽  
Miha Ravnik ◽  
Ivan I. Smalyukh
Keyword(s):  
Self Assembly ◽  
Colloidal Particles ◽  
Dielectric Anisotropy ◽  
Debye Screening Length ◽  
Surface Charges ◽  
Screening Length ◽  
Charged Colloids ◽  
Effective Pair ◽  
Anisotropic Elastic ◽  
Pair Interactions

The physical behavior of anisotropic charged colloids is determined by their material dielectric anisotropy, affecting colloidal self-assembly, biological function, and even out-of-equilibrium behavior. However, little is known about anisotropic electrostatic screening, which underlies all electrostatic effective interactions in such soft or biological materials. In this work, we demonstrate anisotropic electrostatic screening for charged colloidal particles in a nematic electrolyte. We show that material anisotropy behaves markedly different from particle anisotropy. The electrostatic potential and pair interactions decay with an anisotropic Debye screening length, contrasting the constant screening length for isotropic electrolytes. Charged dumpling-shaped near-spherical colloidal particles in a nematic medium are used as an experimental model system to explore the effects of anisotropic screening, demonstrating competing anisotropic elastic and electrostatic effective pair interactions for colloidal surface charges tunable from neutral to high, yielding particle-separated metastable states. Generally, our work contributes to the understanding of electrostatic screening in nematic anisotropic media.

Heat-Shielding and Self-Cleaning Smart Windows: Near-Infrared Reflective Photonic Crystals with Self-Healing Omniphobicity via Layer-by-Layer Self-Assembly

2018 ◽  
Vol 10 (26) ◽  
pp. 22731-22738 ◽  
Author(s):  
Chiaki Nakamura ◽  
Kengo Manabe ◽  
Mizuki Tenjimbayashi ◽  
Yuki Tokura ◽  
Kyu-Hong Kyung ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Self Assembly ◽  
Near Infrared ◽  
Layer By Layer ◽  
Self Healing ◽  
Smart Windows ◽  
Self Cleaning ◽  
Heat Shielding

scholarly journals Exploiting the equilibrium dynamics in the self-assembly of inorganic macrocycles based upon polyoxothiometalate building blocks

2016 ◽  
Vol 52 (58) ◽  
pp. 9109-9112 ◽  
Author(s):  
Hongying Zang ◽  
Andrew Surman ◽  
Deliang Long ◽  
Leroy Cronin ◽  
Haralampos N. Miras
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
The Self ◽  
Equilibrium Dynamics

Manipulation of the equilibrium dynamics allowed access to new thermodynamic minima and formation of two new inorganic macrocycles, {Mo16} = {(Mo2O2S2)8(OH)16(C4O4)2}4− and {Mo12} = {(Mo2O2S2)6(OH)12(CH3COO)2}2−.

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