Solvent Dispersion Method Research Articles

Mo2Ti2C3 and PTFE synergistically functionalized corrosion-resistant, thermally conductive, super abrasion-resistant epoxy resin composite coating

Epoxy resin (EP) matrix composites are a widely used polymer-based protective coating material. However, the low lubricity leads to frictional wear problems that make their large-scale development and application a serious challenge. Based on this, a multifunctional composite coating (MPT-EP) with low wear, high lubricity, high thermal conductivity, and corrosion resistance was prepared by introducing polytetrafluoroethylene (PTFE) and lamellar Mo2Ti2C3 as a composite lubricant into epoxy resin matrix using a simple solvent dispersion method. The results showed that the introduction of the composite lubricant resulted in enhanced hardness and mechanical properties of the composite coating. Compared with the single epoxy resin coating (0.31), the friction coefficient (COF) of the composite coating was only 0.22, and the friction surface did not show obvious abrasion marks. The surface temperature of the composite coating was up to 51.4 °C when it was placed on a hot bench at 60 °C for 60 s. In addition, the COF of the composite coating did not change significantly after being immersed in acid, alkali and salt solutions. Therefore, the Mo2Ti2C3-induced multifunctional epoxy resin matrix composites have important application potential and research value in the field of ultra-wear-resistant and high lubrication protective coatings.

Properties of TiO2/PDMS-Ag Composites as Antibacterial Self Cleaning

TiO2 and TiO2-PDMS/Ag (PDMS = polydimethylsiloxane) composites have been prepared. The synthesis was carried out by preparing TiO2 using ball milling technique for 6, 8 and 10 hours, with the composition of TiO2: ball milling = 1:15; 1:20; and 1:25 (g/g). Furthermore, the TiO2-PDMS/Ag composite was synthesized through the solvent dispersion method with the aid of ultrasonication. The preparation of TiO2-PDMS/Ag composites was carried out with several compositions of TiO2, PDMS and Ag, as well as milling times, aiming to determine the effect of compositions and time of ball milling process on decreasing of TiO2 particle size. The addition of Ag to the TiO2-PDMS composites was carried out to investigate the effect of Ag on the antibacterial activity. TiO2-PDMS/Ag composite coating on glass was done by spray coating method. While the antibacterial activity was measured by determining the zone of inhibition by disc diffusion method against Staphylococcus aurous and Escherichia coli. The results exhibited that the ball milling treatment and milling time affected the change in the crystal size of TiO2. The highest composition of TiO2: ball milling at 1:25 for 10 hours was able to reduce the crystal size of TiO2 from 65.81 nm to 46.17 nm. The other hand, the observation of the physical properties of the contact angle of glass coated TiO2-PDMS/Ag composites before irradiation obtained 107° and after irradiation with visible light the contact angle decreased to 56°, which shows that the TiO2-PDMS/Ag composites exhibit photocatalytic activity in the presence of TiO2/Ag. Furthermore, the observation of antibacterial activity on the TiO2-PDMS/Ag as a self-cleaning photocatalytic materials resulted that the largest inhibition zone reached 11.37 mm, so that the TiO2/PDMS-Ag composites had great potential as an active antibacterial self-cleaning.

Gefitinib encapsulation based on nano-liposomes for enhancing the curative effect of lung cancer

ABSTRACT Gefitinib (GEB) is one of the drugs used for patients with epidermal growth factor receptor (EGFR)-positive mutations in non-small cell lung cancer (NSCLC). However, application of GEB is limited by its low water solubility, stability, and utilization rate, especially the side effects while GEB is given by oral. In this study, nanoliposome was used as a carrier to prepare nanoliposome compound drug (GL) by embedding GEB in the nanoliposome perfectly combined with green nontoxic solvent and thin-film dispersion method. The nanoliposome structure was expected to improve the water solubility and biocompatibility of GEB, thus improving the effect of cancer treatment. The surface electronegative nanoliposomes can effectively avoid protein adsorption and prolong the circulation time in vivo. Meanwhile, the ratio of lecithin to cholesterol (LE/CH) was explored to maximize the encapsulation efficiency of nanoliposome. Subsequent test results showed that GL exhibited better stability, smaller particle size and higher encapsulation efficiency. In addition, in vitro drug release curve also further confirmed that GL had a promising drug sustained-release effect. In particular, a series of in vitro tests such as cell activity, apoptosis, colony formation, scratch, invasion, and cell cycle assays were performed. The results indicated that GL significantly enhanced the pro-apoptotic effect on A549 cells. Most cell cycles of A549 cells were blocked in the G0/G1 phase influenced by GL, thus inhibiting the proliferation of cancer cells. In vivo anti-tumor studies showed that compared with pure GEB, GL had a significant inhibiting effect on NSCLC. In conclusion, the GL which was synthesized by a simple method in this study significantly improved the treatment effect of cancer cells, which proved that the nanoliposome carrier had an excellent application prospect in the treatment of lung cancer.

Investigation of steady state rheological properties and sedimentation of coated and pure carbonyl iron particles based magneto-rheological fluids

Abstract MR fluids face a major problem of sedimentation rate due to the high- density difference between the magnetic particles and the carrier medium that affects the performance of the magnetorheological devices. In this work, two MRF samples are prepared, where MRF-1 and MRF-2 are pure and coated carbonyl iron particles (CIPs) based MR fluids. The surface modification of the CIPs is performed using the solvent dispersion method to improve the sedimentation rate. The spherical shape and particle size analysis of the pure CIPs and coated CIPs’ morphology is investigated using the Scanning Electron Microscope (SEM). The Thermal Gravimetric Analysis (TGA) shows that the coated CIPs have high thermal stability and confirm that 6% by wt. coating is present in the coated sample. The chemical bonding of the coated CIPs is detected using the Fourier Transform Infrared Spectroscopy (FT-IR). The saturation magnetization (Ms) of pure and coated CIPs is 245 emu/g and 120 emu/g, respectively, at 15 kOe, which is obtained by using a superconducting quantum interface device (SQUID). The rheology flow curve properties show that MRF-1 and MRF-2 exhibit yield stress of about 10 kpa and 9 kpa, respectively, for varying magnetic fields ranging from 0 to 343 kA/m. The Herschel-Bulkley model is fitted with the experimental data and the shear thinning behaviour is observed for both MR fluids. The sedimentation study shows that MRF-2 has better settling rate than MRF-1, which is observed by using the visual observation method up to 600 h.

Phytochemical screening and cytotoxicity evaluation of crude extracts: Toxicity comparison of crude extracts and its ethosomal formulations.

Combined plant extracts of Phyllanthus niruri, Croton tiglium, and Zingiber officinale are reported to have potential pharmacological applications. Ethosomes have a unique ability of encapsulating drugs or plant extracts with varying hydrophobicities in the phospholipid bilayer. To explore cytotoxicity of the combined plant extracts and ethosome loaded combined plant extracts for topical delivery. To study effect of ethosomes loaded combined plant extracts using HaCaT cells model treated with testosterone. Dried powder of plant was extracted with ethanol using Soxhlet and cold macerations. Total phenolic and flavonoid contents were also determined using established methods. The combined extract loaded ethosome formulation was prepared by solvent dispersion method. The plant extracts loaded ethosomes formulation with a vesicle size range 1524.6-167.7nm was prepared. HaCaT cells treated with testosterone negative control showed an IC50 value of 27±1.0. Thw standard marketed topical minoxidil (1% solution) treated cells with testosterone showed an IC50 value 33±1.0 and the combined plant extracts loaded ethosomes with testosterone showed an IC50 value 30±1.0. Morphological alterations of rat skin exposed to the combined plant extract loaded ethosomes solution were assessed and compared with untreated skin and negative control. The preclinical safety was investigated employing an in vitro cytotoxicity and histopathological study. The cell line study results confirmed that the combined plant extracts loaded ethosomes inhibits testosterone and increase cell viability closer to that of standard drug minoxidil. According to our histopathological study, the combined plant extract loaded ethosomal formulations did not cause any damage to the rat skin layer.

Thermal transfer, interfacial, and mechanical properties of carbon fiber/polycarbonate-CNT composites using infrared thermography

Electrical resistance (ER) and thermogram measurements were used to evaluate thermal transfer, interfacial and mechanical properties of carbon fiber reinforced thermoplastic polycarbonate composites. Carbon nanotubes (CNTs) were fairly uniformly dispersed in polycarbonates using a solvent dispersion method. The CNTs were then further dispersed with an additional time using a twin screw extruder. The effect of CNT on the mechanical properties of polycarbonate was evaluated using a thin film tensile test. For thermogram to evaluate the transferring temperature the composite was placed on a hotplate and copper wires were inserted in the composite at uniform thickness intervals. Due to the different inherent thermal conductivity of CNT, ER was measured to detect thermal changes in the carbon fiber/CNT-polycarbonate composites. The comparison of interlaminar shear strength (ILSS) was to investigate effects of CNT on mechanical and interfacial properties. The uniform distribution of CNTs affected all of these properties in carbon fiber-reinforced thermoplastic composite. Furthermore, heat transfer and heat release become more rapid with the addition of CNT than the without case.

Interfacial and Mechanical Properties of Carbon Fiber Reinforced Polycarbonate (PC) Film and PC Fiber Impregnated Composites

Currently, continuous polymer fibers are usually manufactured in versatile forms such as, aramid fiber. In this study, continuous polycarbonate (PC) fiber having the uniform diameter was manufactured from a thermoplastic PC resin using a twin screw extruder. Carbon nanotubes (CNTs) were uniformly dispersed in the PC resin, using a solvent dispersion method. The effect of CNT on the mechanical properties of PC fiber was analyzed statistically, using Weibull distribution, by single PC fiber tensile test. Dynamic contact angle was measured to compare the surface energies of PC fiber and PC-CNT fiber on the water droplet. The difference in the wetting patterns was also observed by injecting a solvent between two fibers. Tensile strength and Young’s modulus of the PC fiber was significantly increased by the addition of even a small amount of CNT. This improvement can be attributed to the excellent reinforcing and stress transferring effects of the CNT filler. Composites were made of both types of PC film and PC fiber as a matrix and their impregnation properties were investigated by inspection of photographs of their cross-sections. The mechanical properties of the two-types of composites were also compared by tensile testing. From the cross-sectional fractography and the permeated PC weight, PC fiber type exhibited better impregnation property than the PC film type, and thus resulted in the improved tensile strength.

Effect of Binary Organic Solvents Together with Emulsifier on Particle Size and In vitro Behavior of Paclitaxel-Encapsulated Polymeric Lipid Nanoparticles.

Biodegradable nanoparticles with diameters between 100 nm and 500 nm are of great interest in the contexts of targeted delivery. The present work provides a review concerning the effect of binary organic solvents together with emulsifier on particle size as well as the influence of particle size on the in vitro drug release and uptake behavior. The polymeric lipid nanoparticles (PLNs) with different particle sizes were prepared by using binary solvent dispersion method. Various formulation parameters such as binary organic solvent composition and emulsifier types were evaluated on the basis of their effects on particle size and size distribution. PLNs had a strong dependency on the surface tension, intrinsic viscosity and volatilization rate of binary organic solvents and the hydrophilicity/hydrophobicity of emulsifiers. Acetone-methanol system together with pluronic F68 as emulsifier was proved to obtain the smallest particle size. Then the PLNs with different particle sizes were used to investigate how particle size at nanoscale affects interacted with tumor cells. As particle size got smaller, cellular uptake increased in tumor cells and PLNs with particle size of ~120 nm had the highest cellular uptake and fastest release rate. The paclitaxel (PTX)-loaded PLNs showed a size-dependent inhibition of tumor cell growth, which was commonly influenced by cellular uptake and PTX release. The PLNs would provide a useful means to further elucidate roles of particle size on delivery system of hydrophobic drugs.

Effect of Silica Nanotube Surface Modification on the Physical Properties of Nanocomposites with Poly(methyl methacrylate)

Poly(methyl methacrylate) (PMMA)/silica nanotube (SNT) nanocomposites were prepared by a melt dispersion method using a twin screw extruder and a chloroform-based solvent dispersion method. After removing the template by calcination or organic solvent treatment, the SNT surface was modified by methacryloxypropyl trimethoxysilane (MPMA). The effects of SNT template removal, surface modification, and nanocomposite preparation method on the physical properties of PMMA/SNT nanocomposites were analyzed. The dispersion of SNTs in PMMA was analyzed using transmission electron microscopy. The thermal properties were evaluated using differential scanning calorimetry and thermogravimetric analysis. The mechanical properties of the nanocomposites were analyzed using a universal testing machine and the light transmittance of the nanocomposites was measured using UV-VIS-NIR spectrophotometry. As the SNT increased, the flexural modulus of SNT/PMMA nanocomposites increased. In particular, the surface modified SNT nanocomposite with 5% content by solvent dispersion method showed 49% improvement in flexural modulus compared to virgin PMMA. The tensile strength of nanocomposites decreased with the increase of SNT content. Nanocomposite containing surface modified SNT was higher in tensile strength than that of SNT without surface modification. The dispersion of SNT in the nanocomposite was better by surface modification of SNT, regardless of the preparation method (melt or solvent) of the nanocomposite. However, the light transmittance was more dependent on the SNT template removal method than the SNT surface modification, and ethanol extraction showed higher light transmittance than the calcination method.

Preparation and characterization of high performance NBR/cobalt (II) chloride coordination composites

Acrylonitrile-butadiene rubber (NBR) composites filled with Cobalt (II) Chloride (CoCl2) particles were prepared by a solvent dispersion method. Acetone was selected as solvent for NBR and CoCl2. To directly enhance the interaction between NBR and CoCl2, a coordination reaction was generated by hot pressing at 200 °C. Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV–vis), and x-ray photoelectron spectroscopy (XPS) were employed to investigate the coordination reaction. Results showed that the coordination reaction occurred between the nitrile groups (−CN) of NBR and cobalt ions (Co2+) of CoCl2. Compared with the properties of pure NBR, the tensile strength of NBR/CoCl2 composites filled with 10 parts per hundreds of rubber (phr) CoCl2 increased 2200%. Scanning electron microscopy (SEM) indicated that the CoCl2 particles were dispersed in the NBR matrix homogeneously. The indistinguishable interface between CoCl2 particles and NBR matrix indicated good compatibility. Additionally, thermogravimetric analysis (TGA) showed that coordination reaction improved heat resistance of NBR matrix.

Effect of Pr/Ce addition on the catalytic performance and SO2 resistance of highly dispersed MnOx/SAPO-34 catalyst for NH3-SCR at low temperature

Based on ionic polarization, a series of MeOx-MnOx/SAPO-34 (Me=Pr or Ce) catalysts were prepared by a simple solvent dispersion method and their low temperature ammonia-selective catalytic reduction (SCR) performance were tested with and without SO2. The highly dispersed MnOx/SAPO-34 catalyst was doped with Pr and showed better low temperature catalytic activity (140–280°C) than that of the Ce-modified MnOx/SAPO-34. Also, the PrOx-MnOx/SAPO-34 presented good SO2 resistance performance with 100ppm SO2 at 200°C. Additionally, the fresh and SO2-poisoned catalysts were characterized by FE-SEM, BET, XRD, XPS, H2-TPR, NH3-TPD and TG analysis. The results indicated that there was no obvious change in the crystal structure of the PrOx-MnOx/SAPO-34 sample. The MnOx/SAPO-34 catalyst was doped with Pr, which prevented the catalyst from being sulfated and inhibited the formation of ammonia sulfate on the catalyst surface. The SO2 may favor combination with PrOx over MnOx, which could form praseodymium sulfate and protect the manganese active sites to some extent, in accordance with the theory of ionic polarization. More than 80% NOx conversion was provided by PrOx-MnOx/SAPO-34 catalysts in the presence of 100ppm SO2 at 200°C.

Xanthan Gum Coated Mucoadhesive Liposomes for Efficient Nose to Brain Delivery of Curcumin

Background: The objective of this study was to develop liposomal mucoadhesive drug delivery system for the delivery of curcumin via nasal route, to avoid hepatic first pass metabolism, to increase residence time and to investigate its nose to brain delivery potential. Methodology: The liposomes were prepared by solvent dispersion method using soya lecithin and cholesterol as a lipid phase and xanthan gum as a mucoadhesive polymer. The liposomes were evaluated for particle size, entrapment efficiency, mucoadhesion, DSC, ex vivo permeation, histopathological study, in vitro drug release, and in vivo study for the estimation of drug in brain after intranasal administration. Results and Discussion: The particle size was in the range of 100.2-150 nm with good stability and controlled release characteristics without any deleterious effect on nasal mucosa of rat. When administered via intranasal route the liposomes showed higher drug distribution in brain (1240 ng) compared to drug solution (65 ng). Conclusion: The results of the in vivo study suggests that the xanthan gum coated curcumin liposomes is a promising drug delivery system to deliver drug to the brain through nasal route. Keywords: Curcumin, liposomes, mucoadhesion, nose to brain delivery, solvent dispersion method, xanthan gum.

Research on a Coated Method for Ceramic Proppant

Due to the disadvantage of the traditional proppant, such as the low strength, poor acid corrosion resistance, embedding and flowback and so on, a new coated proppant was developed to deal with these problems. As the coating material, the natural gel was used to coat proppant. Different from the traditional mechanical mixing method, the means to make coated ceramic was the solvent dispersion method through the process of emulsification, cross-linking and dehydration dispersion. The strength of coated proppant was tested in different coated conditions. According to the result of test, the ceramic was coated under the optimum condition. Then the roundness, sphericity, acid solubility, crush resistance and surface structure of coated ceramic were compared with the uncoated ceramic. The experimental results showed that the optimal condition was as follows: 0.08 g/ml of gel concentration, 15/2 of ceramic/gel (g/g), 0.025 g/ml of emulsifier concentration, 20min of emulsifying time, 1/10 of water/oil rate. The coated ceramic prepared at this condition had the best performance, compared with the common ceramic, and its sphericity and acid solubility were greatly improved, bulk density reduced 7%. And the proppant surface was very smooth, the crush resistance was almost zero.

Mechanical and interfacial evaluation of CNT/polypropylene composites and monitoring of damage using electrical resistance measurements

Carbon nanotube (CNT)/polypropylene (PP) composites were compounded using a solvent dispersion method to more uniformly disperse the filler. A twin screw extruder was then used to manufacture specimens. The effect of low CNT concentrations on the mechanical and interfacial properties of PP were investigated using tensile and impact tests as well as a pull-out test of a microdroplet of the composite, on a single fiber. Low concentrations of CNT resulted in small, but significant increases, in Young’s modulus, impact strength and interfacial adhesion . The increase in these mechanical properties is attributed to good reinforcing effects of the CNT filler. Measurement of the change in electrical resistance during bending and fatigue loading was used to monitor internal damage in the CNT/PP composite specimens. For CNT/PP composites with low CNT concentrations, these resistance measurements provide useful insight into internal failure, during cyclic loading.

Measurements of size distribution nanoparticles in ultraviolet‐curable methacrylate‐based boehmite nanocomposites

AbstractA deep study on the possibility to increase the quality of the dispersion of organically modified Boehmite nanoparticles into photo‐polymerizable methacrylic‐siloxane monomers, to be used as coatings, was conducted using unconventional indirect analyses. The nanocomposite were produced using two different procedures, starting from the conventional “solvent dispersion method.” The two procedures used differ for the technique used to obtain the dispersion of Boehmite, i.e., sonication or magnetic stirring and for the time used in each procedure. The efficiency of each method of preparation of nanostructured systems was analyzed, both in the liquid (uncured) and ultraviolet (UV) cured state. First, dynamic light scattering and rheological measurements were performed on the liquid suspensions, supplying experimental data used in proper theoretical models to estimate the dimensions and distribution of Boehmite particles. The suspensions obtained with the two different methods were, then, UV cured obtaining thin and thick films, on which scanning electron microscopy and transmittance measurements were performed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Sustained drug release system using porous structured poly(l-lactic acid) fabricated by solvent dispersion method

Poly(l-lactic acid) (PLLA) is a synthetic polyester that has been widely used in medicine. However, the degradation of PLLA can be accompanied by an inflammatory reaction, and it is difficult to control the duration of the degradation of PLLA. Thus, a sustained NSAID release porous structured PLLA was fabricated by using a solvent dispersion method. This novel drug release system would provide a consistent release of NSAIDs at a desirable concentration. PLLA and NSAIDs (Sulindac) were dissolved in methylene chloride. After they had homogenously dispersed, the solvent was isolated. Non-porous and porous PLLA substrates mixed with various concentrations (1, 5, and 9 %) of Sulindac were prepared. A morphological examination with a scanning electron microscope was performed. The elution experiment of Sulindac was implemented for 5 days. The drug release and the degradation of the compound in simulated body fluids were examined. No Sulindac particles were identified on the surface of the non-porous compound, however, they were found on that of the porous one. No porosity was found in the cross-section of the non-porous compound. During a 5 day period, the amount of the release of Sulindac was 3.9–17.6 mg/L in the non-porous compound and 21.5–35.1 mg/L in the porous one. In the non-porous compound, the amount of Sulindac released was found to be 3–5 ppm for 20–150 days. In the porous compound, it was found to be 137.7 ppm for 10 days initially. As time elapsed, however, there was a tendency of the release rate to gradually decrease. The authors attempted to prepare a sustained drug release system, which can maintain the concentration of drugs during a longer period in an in vivo setting. This compound could be applied in various ways in the field of material engineering.

Novel elastomer dye-functionalised POSS nanocomposites: Enhanced colourimetric, thermomechanical and thermal properties

Nanocomposites consisting of poly(styrene-b-butadiene-b-styrene) (SBS) and polyhedral oligomeric silsesquiox- anes (POSS) were prepared using a solvent dispersion method. POSS molecules were functionalised with two dichlorotri- azine reactive dyes (CI Reactive Blue 4, CI Reactive Red 2) prior to compounding. Infrared spectroscopy confirmed func- tionalisation. Scanning electron microscopy revealed an increase in filler aggregation with concentration, with preferential phase selectivity. Ultraviolet spectroscopy and colourimetry confirmed colour uniformity and suggested that colour inten- sity could be controlled. Functionalised POSS improved thermal stability by imparting restrictions on SBS chain motions. Tensile stress-strain analysis revealed an increase in modulus with filler concentration, while creep deformation decreased and permanent strain increased with POSS content. Storage modulus, loss modulus and glass transition temperature increased with filler content due to effective SBS-POSS interaction. Nanocomposite properties were influenced by the phase the filler was dispersed throughout and the structure of the dye chromophore.

Novel elastomer‐dumbbell functionalized POSS composites: Thermomechanical and Morphological Properties

AbstractNanocomposites consisting of poly(styrene‐b‐butadiene‐b‐styrene) (SBS) and polyhedral oligomeric silsesquioxanes (POSS) were prepared using a solvent dispersion method. Dumbbell‐shaped POSS fillers were prepared using diacyl chlorides to bridge the POSS molecules. Infrared spectroscopy confirmed functionalization. Scanning electron microscopy revealed an increase in filler aggregation with concentration, with preferential phase selectivity. Polydispersity increased with filler concentration while d spacing was influenced by phase selectivity and domain‐filler compatibility. Functionalized POSS improved thermal stability by imparting restrictions of SBS chain motions. Tensile stress–strain analysis revealed an increase in modulus, yield strength, and strain hardening with filler concentration, while creep deformation decreased and permanent strain increased with POSS content. Storage modulus, loss modulus, and glass transition temperature increased with filler content due to effective SBS–POSS interaction. Nanocomposite properties were influenced by filler concentration, the phase of the filler was dispersed throughout and the length of the alkyl “barbell” on the dumbbell‐shaped POSS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Kinetics of nanocolloids in the aligned domain of octylcyanobiphenyl and aerosil dispersion

In this study we explore the interesting kinetics of nanocolloids formed by the solvent dispersion method (SDM) in an aligned matrix of octylcyanobiphenyl (8CB) liquid crystals and aerosil nanoparticles. The presence of alignment changes the behaviour of the induced crystallisation (IC), and melting transition (K–SmA) observed in the aligned nanocolloidal liquid crystal samples when compared with unaligned samples. Heating‐rate‐dependent experiments were performed for the aligned and unaligned samples at various heating ramp rates varied from 20 to 1 K min−1 using a calorimetric technique. In the aligned samples, the IC transition peak shifts towards higher temperature, whereas the melting transition peak shifts towards lower temperature. The IC peak shows an increase in enthalpy whereas the melting transition shows a decrease following an Arrhenius behaviour. The presence of alignment increases the activated kinetics of the system. This behaviour can be explained in terms of molecular interaction between aligned domains of nanocolloids in the 8CB matrix which makes the material stiffer.

Calorimetric study of activated kinetics of the nematic and smectic phase transitions in an aligned nano-colloidal liquid crystal+aerosil gel

This study explores the calorimetric analysis of an aligned nano-colloidal aerosil dispersed octyl-cyanobiphenyl gel. This system was prepared by solvent dispersion method (SDM). Heating scans were performed at different heating rates from 20 to 1 K min−1 using DSC. Aligned samples follow Arrhenius behavior and showed a temperature shift in SmA-N and N-I transitions towards lower temperature. These samples show a decreased activated kinetics and an interesting relationship with their enthalpy. This behavior can be explained in terms of surface and molecular interaction between aerosil nano-particles and 8CB molecules and produced strain in the system.