scholarly journals A modified Rayleigh-Plesset equation for a liquid-crystalline shelled microbubble

2019 ◽  
Author(s):  
James Cowley ◽  
Anthony J. Mulholland ◽  
Anthony Gachagan
Keyword(s):  
Drug Delivery ◽  
Relaxation Time ◽  
Natural Frequency ◽  
Liquid Crystalline ◽  
Physical Characteristics ◽  
Crystalline Material ◽  
Physical Parameters ◽  
First Time ◽  
Protein Shell ◽  
Liquid Crystalline Material

Premanufactured shelled microbubbles composed of a protein shell are currently licensed as ultrasound imaging contrast agents. Current research is focussing on using the protein shelled microbubbles as transportation mechanisms for localised drug delivery particularly in the treatment of various types of cancer. For the very first time, a theoretical model is developed for an incompressible, gas loaded shelled microbubble with a thin shell composed of a liquid-crystalline material. We show that liquid-crystalline shelled microbubbles exhibit significantly different physical characteristics from commercial protein shelled microbubbles such as Sonovue and Optison. The authors propose that these significantly different physical characteristics may enhance localised drug delivery. We use the technique of linearisation to predict the shelled microbubble’s natural frequency and relaxation time. These physical parameters strongly influence sonoporation which is the mechanism that is used for localised drug delivery. The influence of the material properties of the shell on the natural frequency and relaxation time are discussed. We have discovered that liquid-crystalline shelled microbubbles have a relaxation time that is 10 times longer than Sonovue and Optison.

scholarly journals ‘Quasi-Tricritical’ and Glassy Dielectric Properties of a Nematic Liquid Crystalline Material

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 297 ◽  
Author(s):  
Aleksandra Drozd-Rzoska
Keyword(s):  
Relaxation Time ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Strong Electric Field ◽  
Low Frequency ◽  
Ionic Species ◽  
Crystalline Material ◽  
Isotropic Liquid ◽  
The Impact ◽  
Liquid Crystalline Material

Results of dielectric studies in the nematic and isotropic liquid phases of pentylcyanobiphenyl (5CB), a model rod-like liquid crystalline material, are shown. They are based on the discussion of the evolution of dielectric constant ( ε ), its changes under the strong electric field (nonlinear dielectric effect, NDE), and finally, the primary relaxation time. It is shown that changes in ε T and NDE are entirely dominated by the impact of pretransitional fluctuations (pre-nematic and pre-isotropic, respectively) which are associated with the weakly discontinuous character of the isotropic–nematic phase transition. This influence also extends for the low-frequency, ionic species dominated, region. Notable, that the derivative-based and distortions sensitive analysis revealed the tricritical nature of the I-N transition. Although the glass transition in 5CB occurs in the deeply supercooled state at T g ≈ − 68 ° C , the dynamics (changes of the primary relaxation time) follow a previtreous pattern both in the isotropic and in the nematic phase. Finally, the discussion of the ’molecular’ vs. ‘quasi-critical’ characterizations of the isotropic and nematic phases is presented. It shows the evident prevalence of the ‘quasi-critical-picture’, which offers the consistent temperature parameterization in the total tested temperature range.

A New Liquid-Crystalline Material. Transition Metal-Poly(yne) Polymers

1979 ◽  
Vol 12 (5) ◽  
pp. 1016-1018 ◽  
Author(s):  
S. Takahashi ◽  
E. Murata ◽  
M. Kariya ◽  
K. Sonogashira ◽  
N. Hagihara
Keyword(s):  
Transition Metal ◽  
Liquid Crystalline ◽  
Crystalline Material ◽  
Liquid Crystalline Material

Fabrication of polycrystalline thin films of liquid crystalline materials by solution process and its application to OFETs

2008 ◽  
Vol 1091 ◽  
Author(s):  
Hiroaki Iino ◽  
Jun-ichi Hanna
Keyword(s):  
Thin Films ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Solution Process ◽  
Crystalline Material ◽  
Crystalline Materials ◽  
Polycrystalline Thin Films ◽  
Channel Performance ◽  
Liquid Crystalline Materials ◽  
Liquid Crystalline Material

AbstractWe have fabricated polycrystalline OFETs of two different liquid crystalline materials i.e., ω,ω'-dihexylquaterthipohene (6-QTP-6) and N, N'-ditridecylperylenediimide (13-Per-13) by solution process. Liquid crystalline materials help fabricating uniform thin films on the substrate when spin-coated at their temperature range of liquid crystalline phase. The FETs fabricated with 6-QTP-6 exhibited p-channel performance and its mobility was determined to be 0.04 cm2/Vs, which was comparable to that determined by time-of-flight experiments. The FETs fabricated with 13-Per-13 exhibited n-channel performance and its FET mobility was 0.008 cm2/Vs, while the mobility was increased up to 0.11 cm2/Vs after thermal annealing of the film at a liquid crystalline temperature of 220°C for an hour. Judging from these facts, the grain boundaries are controlled not so as to across the conduction channels formed by self-aligned π-conjugated aromatic cores in liquid crystalline molecules. We conclude that liquid crystalline material is a good candidate for quality polycrystalline thin films for OFETs.

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