scholarly journals Phase transition and dewetting of a 5CB liquid crystal thin film on a topographically patterned substrate

RSC Advances ◽  
2019 ◽  
Vol 9 (38) ◽  
pp. 21685-21694 ◽  
Author(s):  
Palash Dhara ◽  
Rabibrata Mukherjee
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Liquid Crystal ◽  
Patterned Substrates ◽  
Thermally Induced ◽  
Patterned Substrate ◽  
5Cb Liquid Crystal

Thermally induced nematic to isotropic (N–I) phase transition and dewetting of 5CB liquid crystal thin films on flat and topographically patterned substrates.

INDUCED CHANGES OF THERMOTROPIC PROPERTIES OF PHASE TRANSITIONS BETWEEN SMECTIC A MESOPHASE AND ISOTROPIC LIQUID: EFFECT OF SURFACES

2006 ◽  
Vol 20 (14) ◽  
pp. 821-833 ◽  
Author(s):  
ARIF NESRULLAJEV ◽  
ŞENER OKTIK
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Phase Transitions ◽  
Isotropic Liquid ◽  
Smectic A ◽  
Phase Transition Temperatures ◽  
Smectic A Phase ◽  
Induced Changes ◽  
Thermotropic Properties

In this work, the effect of thin films on the thermotropic and thermo-optical properties and peculiarities of the phase transitions between the smectic A and isotropic liquid have been investigated. Peculiarities of the heterophase regions of the straight smectic A-isotropic liquid and reverse isotropic liquid-smectic A phase transitions have been studied. Change of morphologic properties of the heterophase regions, shift of the phase transition temperatures and the change of temperature widths of these heterophase regions under thin film influence have been observed.

Predicting surface anchoring: molecular organization across a thin film of 5CB liquid crystal on silicon

2012 ◽  
Vol 3 (2) ◽  
pp. 573-579 ◽  
Author(s):  
A. Pizzirusso ◽  
R. Berardi ◽  
L. Muccioli ◽  
M. Ricci ◽  
C. Zannoni
Keyword(s):  
Thin Film ◽  
Liquid Crystal ◽  
Molecular Organization ◽  
Surface Anchoring ◽  
5Cb Liquid Crystal ◽  
Liquid Crystal On Silicon

Thermochromic VO2 Thin Film Prepared by Post Annealing Treatment of V2O5 Thin Film

2009 ◽  
Vol 79-82 ◽  
pp. 747-750 ◽  
Author(s):  
Dong Qing Liu ◽  
Wen Wei Zheng ◽  
Hai Feng Cheng ◽  
Hai Tao Liu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Annealing Treatment ◽  
Simple Method ◽  
X Ray ◽  
Post Annealing ◽  
Vo2 Thin Films

Thermochromic vanadium dioxide (VO2) exhibits a semi-conducting to metallic phase transition at about 68°C, involving strong variations in electrical and optical properties. A simple method was proposed to prepare VO2 thin films from easily gained V2O5 thin films. The detailed thermodynamic calculation was done and the results show that V2O5 will decompose to VO2 when the post annealing temperature reaches 550°C at the atmospheric pressure of less than 0.06Pa. The initial V2O5 films were prepared by sol-gel method on fused-quartz substrates. Different post annealing conditions were studied. The derived VO2 thin film samples were characterized using X-ray diffraction and X-ray photoelectron spectroscopy. The electrical resistance and infrared emissivity of VO2 thin films under different temperatures were measured. The results show that the VO2 thin film derived from the V2O5 thin film annealed at 550°C for 10 hours is pure dioxide of vanadium without other valences. It was observed that the resistance of VO2 thin film with thickness about 600nm can change by 4 orders of magnitude and the 7.5-14μm emissivity can change by 0.6 during the phase transition.

scholarly journals Substrate Induced Polymorphism in Organic Thin Films

2014 ◽  
Vol 70 (a1) ◽  
pp. C728-C728
Author(s):  
Basab Chattopadhyay ◽  
Yves Geerts
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Liquid Crystal ◽  
Charge Transport ◽  
Field Effect Transistors ◽  
Crystal Packing ◽  
Morphological Changes ◽  
Solid Substrate ◽  
Experimental Proof ◽  
Discotic Liquid Crystal

The presence of substrate induced polymorphic phases in thin films is an intriguing phenomenon with the physical and chemical factors responsible for its formation are not yet clearly understood. In particular, this is really crucial in the field of organic electronics, where the charge-transport properties are highly dependent on crystal packing, especially for organic field-effect transistors where charge transport occurs at the interface between the organic semiconductor and the dielectric. In pharmaceutical sector, thin film drug delivery is the new emerging alternative to traditional tablets and oral suspensions. The need to identify and control polymorphism induced by the substrate is thus very crucial. In this presentation, we report the structure and morphological changes associated with a substrate induced polymorphic phases in a discotic liquid crystal and a rod shaped DPP-thiophene-based molecule [1, 2]. The bulk compound and the thin films are characterized by a combination of various X-ray diffraction methods to investigate the structural properties. Atomic force microscopy and polarized optical microscopy are used to determine the thin film morphologies. This is the first experimental proof of presence of a substrate induced phase in discotic liquid crystal showcasing an unique example where the 2-D liquid crystalline phase converts to a 3-D crystal plastic phase due to nucleation caused by the solid substrate over a time scale of a month or longer. The presentation also highlights the importance of polymorphism in DPP-thiophene-based material and the specific organization that could arise from the interaction with the substrate depending on the growing conditions. Here the exact structural and the spectroscopic signatures of different polymorphic forms in bulk and in thin films could be identified. These are clearly factors to consider to induce the formation of a particular polymorph and to help to design deposition methodologies.

Synthesis of SnSe2 thin films by thermally induced phase transition in SnSe

2017 ◽  
Vol 724 ◽  
pp. 62-66 ◽  
Author(s):  
Jeewan Sharma ◽  
Randhir Singh ◽  
Harinder Singh ◽  
Tejbir Singh ◽  
Palwinder Singh ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Thermally Induced

scholarly journals Thermally induced bilayered crystals in a solution-processed polycrystalline thin film of phenylterthiophene-based monoalkyl smectic liquid crystals and their effect on FET mobility

RSC Advances ◽  
2017 ◽  
Vol 7 (89) ◽  
pp. 56586-56593 ◽  
Author(s):  
Hao Wu ◽  
Hiroaki Iino ◽  
Jun-ichi Hanna
Keyword(s):  
Thin Film ◽  
Phase Transition ◽  
Liquid Crystals ◽  
Smectic Liquid Crystals ◽  
Polycrystalline Thin Film ◽  
Solution Processed ◽  
Thermally Induced

Herein, a series of asymmetric monoalkyl terthiophene derivatives, Ph-(Tp)3-Cn, (6 ≤ n ≤ 18), were synthesized to study the phase transition from monolayered crystal to bilayered crystal, leading to a significant increase of OFET mobility.

Block Copolymers on a Physically or Chemically Patterned Substrate

2010 ◽  
Vol 123-125 ◽  
pp. 523-526
Author(s):  
Jaeup U. Kim
Keyword(s):  
Thin Films ◽  
Phase Diagram ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Bulk Phase ◽  
Patterned Substrates ◽  
Patterned Substrate ◽  
Bulk Phase Diagram

Patterned substrates are good candidates to enhance the arrangement of nanodomains in block copolymer thin films. Here, I theoretically demonstrate the possibility to self-assemble block copolymers on top of physically or chemically patterned substrates. The presence of substrate pattern not only enhances the alignment of polymers, but also induces novel new morphologies which were not present in the bulk phase diagram.

The thermally induced metal–semiconducting phase transition of samarium monosulfide (SmS) thin films

2009 ◽  
Vol 22 (1) ◽  
pp. 015005 ◽  
Author(s):  
E Rogers ◽  
P F Smet ◽  
P Dorenbos ◽  
D Poelman ◽  
E van der Kolk
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Thermally Induced ◽  
Samarium Monosulfide

scholarly journals Phase transition in magnetic ultra-thin films

2019 ◽  
Vol 128 (1D) ◽  
Author(s):  
Phạm Hương Thảo ◽  
Ngô Thị Thuận ◽  
Phan Thị Hàn Ny
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Integral Method ◽  
Functional Integral ◽  
Spin Fluctuations ◽  
Surface Anisotropy ◽  
Functional Integral Method

<p>In this paper, we study influence of surface anisotropy on the phase transition in antiferromagnetic and ferromagnetic ultra-thin films by using functional integral method. Besides, spin fluctuations are also given to illustrate for these phase transitions. We find that the phase transition temperature of the ultra-thin films may be higher or lower than the phase transition temperature of the corresponding bulk systems, which depends on the surface anisotropy. Moreover, we also determine crossover points at which the phase transition temperature is not influenced by the thickness of the thin film.</p>

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