Miscibility Studies Research Articles

A Miscibility Study of p(MMA-co-HEMA)-Based Polymer Blends by Thermal Analysis and Solid-State NMR Relaxometry.

Ternary amorphous solid dispersions (ASDs) consist of a multicomponent carrier with the aim of improving physical stability or dissolution performance. A polymer blend as a carrier that combines a water-insoluble and a water-soluble polymer may delay the drug release rate, minimizing the risk of precipitation from the supersaturated state. Different microstructures of the ternary ASD may result in different drug release performances; hence, understanding the phase morphology of the polymer blend is crucial prior to drug incorporation. The objective of this study is to investigate the miscibility of the water-insoluble p(MMA-co-HEMA) and water-soluble polymers such as HPC, HPMC, HPMC-AS, and Soluplus. To prepare the polymer blends, p(MMA-co-HEMA) was spray dried in 80/20 and 90/10 (w/w) ratios with one of the water-soluble polymers. Thermal analysis (mDSC and DMA) and solid-state (ss)NMR relaxometry were applied to study the miscibility of these blends. No conclusions regarding miscibility could be drawn from the Tg measurements by thermal analysis. However, phase-separation could be demonstrated in all blends by ssNMR relaxometry. Moreover, by measuring both the T1ρH and T1H relaxation times, domain sizes between 5 and 50 nm could be estimated. This work shows the importance of using complementary analytical techniques to investigate polymer miscibility.

Multiscale Computational Study of Cellulose Acetate-Water Miscibility: Insights from Molecularly Informed Field-Theoretic Modeling.

Cellulose acetate (CA), a prominent water-soluble derivative of cellulose, is a promising biodegradable ingredient that has applications in films, membranes, fibers, drug delivery, and more. In this work, we present a molecularly informed field-theoretic model for CA to explore its phase behavior in aqueous solutions. By integrating atomistic details into large-scale field-theoretic simulations via the relative entropy coarse-graining framework, our approach enables efficient calculations of CA's miscibility window as a function of the degree of substitution (DS) of cellulose hydroxyl groups with acetate side chains. This allows us to capture the intricate phase behavior of CA, particularly its unique miscibility at intermediate substitution, without relying on experimental input. Additionally, the model directly probes CA solution behavior specific to the relative DS at C2, C3, and C6 alcohol sites, providing insights for the rational design of water-soluble CA for diverse applications. This work demonstrates a promising integration of molecularly informed field theories, complementing wet-lab experimentation, for engineering the next-generation polymeric materials with precisely tailored properties.

Application of Different Animal Fats as Solvents to Extract Carotenoids and Capsaicinoids from Sichuan Chili.

Inspired by the proved dissolving power of vegetable oils for non-polar and low-polar natural compounds, animal fats with triglycerides as the major components were investigated as food-grade solvents in this study for the simultaneous extraction of carotenoids and capsaicinoids from Sichuan chili. The dissolving power of lard, beef tallow, chicken fat and basa fish oil in the extraction of er jing tiao chili was firstly compared, where animal oils with worse extraction ratios for carotenoids (0.79 mg/g in average) performed better for the extraction of capsaicinoids (0.65 mg/g in average). Furthermore, the solvent effect of animal fats on the oleo-extracts was evaluated in terms of fatty acid composition, oil quality indexes, crystal polymorphism, melting and crystallization behaviors, where no significant differences were observed between animal fats before and after extraction. The oxidative stability of animal fats could be 1.02- up to 2.73-fold enhanced after extraction and the pungency degree could reach the same spicy level as commercial hotpot oil. In addition, the Hansen solubility parameters of solvents and solutes were predicted for further theoretical miscibility study, which helps to make a better comprehension of the dissolving mechanism behind such oleo-extraction. Overall, animal fats demonstrated their considerable solvent power for extracting carotenoids and capsaicinoids simultaneously from Sichuan chili, which showed significant potential for developing a novel Sichuan spicy hotpot oil with enhanced flavor and stability.

Monophasic coamorphous sulpiride: a leap in physicochemical attributes and dual inhibition of GlyT1 and P-glycoprotein, supported by experimental and computational insights

Study aimed to design and development of a supramolecular formulation of sulpiride (SUL) to enhance its solubility, dissolution and permeability by targeting a novel GlyT1 inhibition mechanism. SUL is commonly used to treat gastric and duodenal ulcers, migraine, anti-emetic, anti-depressive and anti-dyspeptic conditions. Additionally, Naringin (NARI) was incorporated as a co-former to enhance the drug’s intestinal permeability by targeting P-glycoprotein (P-gp) efflux inhibition. NARI, a flavonoid has diverse biological activities, including anti-apoptotic, anti-oxidant, and anti-inflammatory properties. This study aims to design and develop a supramolecular formulation of SUL with NARI to enhance its solubility, dissolution, and permeability by targeting a novel GlyT1 inhibition mechanism, extensive experimental characterization was performed using solid-state experimental techniques in conjunction with a computational approach. This approach included quantum mechanics-based molecular dynamics (MD) simulation and density functional theory (DFT) studies to investigate intermolecular interactions, phase transformation and various electronic structure-based properties. The findings of the miscibility study, radial distribution function (RDF) analysis, quantitative simulations of hydrogen/π–π bond interactions and geometry optimization aided in comprehending the coamorphization aspects of SUL-NARI Supramolecular systems. Molecular docking and MD simulation were performed for detailed binding affinity assessment and target validation. The solubility, dissolution and ex-vivo permeability studies demonstrated significant improvements with 31.88-fold, 9.13-fold and 1.83-fold increments, respectively. Furthermore, biological assessments revealed superior neuroprotective effects in the SUL-NARI coamorphous system compared to pure SUL. In conclusion, this study highlights the advantages of a drug-nutraceutical supramolecular formulation for improving the solubility and permeability of SUL, targeting novel schizophrenia treatment approaches through combined computational and experimental analyses. Communicated by Ramaswamy H. Sarma

Computational investigation of the interaction mechanisms of low‐density polyethylene (LDPE)/polyurethane and low‐density polyethylene (LDPE)/hexane systems as absorbents for oil spill remediation: A DFT study

AbstractThe escalating frequency of oil spill incidents and industrial wastewater discharges necessitates the development of effective remediation strategies. In this study, we conduct a comprehensive computational investigation using density functional theory (DFT) to elucidate the interaction mechanisms within polyethylene (PE) combined with polyurethane (PU) and hexane. The study focuses on adsorption energies, intermolecular interactions, miscibility, and electronic properties, providing a molecular‐level understanding crucial for designing advanced absorbent materials. The investigation reveals that the low‐density polyethylene/polyurethane (LDPE/PU) system exhibits significantly higher adsorption energies (−12.87 kcal/mol) compared to PE/hexane (−7.66 kcal/mol), indicating a robust binding affinity. This discrepancy underscores the superior performance of PE/PU as an absorbent material. The enthalpy results, with ∆H values of −55.75 kcal/mol for PE/hexane‐n‐hexadecane and −66.11 kcal/mol for PE/PU‐n‐hexadecane complexes at 298.15 K, support exothermic adsorption. The more exothermic ∆H for PE/PU indicates stronger interactions during oil absorption than PE/hexane. Additionally, Gibbs free energy change (∆G) values affirm a more favorable process for PE/PU, exhibiting a lower ∆G (−42.54 kcal/mol) compared to PE/hexane (−34.79 kcal/mol). Non‐covalent interaction (NCI) studies confirm the importance of van der Waals forces in both systems, validating their role in the adsorption process. Miscibility studies indicate limited interactions, with PE/PU showing positive enthalpy of mixing. Electronic study demonstrates PE/PU's higher energy gap of 9.19 eV, correlating with superior performance. This research contributes to the fundamental understanding of oil absorption processes and informs the design and optimization of environmentally sustainable and efficient oil‐absorbing materials for remediation applications.Highlights DFT explores polymeric systems, PE/PU and PE/hexane, for oil absorbent. PE/PU excels with −12.87 kcal/mol adsorption energy, surpassing PE/hexane (−7.66 kcal/mol). NCI validates van der Waals forces in both systems, crucial for effective adsorption. Miscibility studies reveal limited interactions. PE/PU's superior 9.19 eV energy gap signifies enhanced absorbent performance. PE/PU excels as an oil‐absorbent material, underlining its overall superiority.

A systematic investigation of single solute, binary and ternary PFAS transport in water-saturated soil using batch and 1-dimensional column studies: Focus on mixture effects

This study aimed to investigate the transport and release of per- and polyfluoroalkyl substances (PFAS), as single solutes and binary and ternary mixtures, and associated competitive sorption effects in water-saturated soil. Batch sorption isotherm and desorption, and one-dimensional miscible displacement studies were conducted. For the batch study, the mixtures exhibited extensive sorption isotherm nonlinearity at aqueous concentrations exceeding 20 µg/L. At and above this threshold, competitive effects significantly decreased PFAS sorption, mostly affecting perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). Importantly, mixture effects exacerbated isotherm nonlinearity and may increase the leaching of PFAS in subsurface soil and groundwater. Further, up to 100% desorption occurred for single solutes and mixtures, indicating that the studied PFAS were weakly sorbed. For the column study, at influent concentrations (21 – 27 µg/L, depending on PFAS) near the threshold, PFOA and PFHxS breakthrough curves (BTC) generally exhibited equilibrium (nonlinear) transport, whereas perfluorooctane sulfonate (PFOS) exhibited nonequilibrium transport, with minimal or no mixture effects. Nonequilibrium transport of PFOS was driven by rate-limited sorption, especially as flow interruption tests confirmed the absence of physical nonequilibrium. The sorption distribution coefficients (Kd) from moment and frontal analyses, and 2-site modelling of the BTC, were consistent with the batch-derived Kd, although comparatively smaller. Such discrepancies may limit the applicability of batch-derived Kd values for predictive transport modelling purposes. Overall, understanding mixture impacts may aid effective predictive modelling of PFAS transport and leaching, especially in aqueous film forming foam (AFFF)-source zone areas associated with elevated PFAS concentrations. At low or environmental PFAS concentrations, mixture effects can be expected to be play a minor role in influencing PFAS transport.

Drug-Polymer Miscibility and Interaction Study as a Preliminary Step in Amorphous Solid Dispersion Development: Comparison of Theoretical and Experimental Data

Drug-Polymer Miscibility and Interaction Study as a Preliminary Step in Amorphous Solid Dispersion Development: Comparison of Theoretical and Experimental Data

Polymeric amorphous dispersion as a carrier to enhance the in vitro dissolution in vivo pharmacokinetics and cytotoxicity of niclosamide

AbstractAmorphous solid dispersion is one of the recent technologies that attracted the pharmaceutical industry to deliver poorly soluble drugs. However, the selection of polymeric carriers and characterization of drug‐polymer interactions need to be performed systemically to develop a stable amorphous delivery system. Solubility parameter analysis was used to screen the polymers. Hot melt extrusion (HME) was used to prepare the polymeric amorphous dispersion. Drug polymer interactions were identified by attenuated total reflection spectroscopy. Solid‐state transformations were characterized by differential scanning calorimetry and powder X‐ray diffraction. In vitro drug release was performed under non‐sink conditions. In vivo pharmacokinetic studies were performed on rats, and MCF‐7 and A‐549 cell lines were used to study the cytotoxicity. Polymer miscibility studies indicated polyvinylpyrrolidone (PVPK17) as a suitable polymer, and 180°C at 50 rpm was the ideal condition in the HME. The analytical tools confirmed the conversion of niclosamide (NCL) to an amorphous state and the existence of hydrogen bond interactions between the drug and the polymer. Prepared solid dispersions were stable for 3 months and showed about 214‐fold improvement in solubility and around 10‐fold improvement in dissolution over pure crystalline NCL. Pharmacokinetic studies showed a 4.04‐fold enhancement in Cmax and a 2.05‐fold enhancement in the area under the plasma concentration‐time curve (AUC0‐24h) compared to crystalline NCL. Cytotoxicity studies also showed a better toxicity profile with a reduction in the IC50 values of NCL in the amorphous solid dispersions. These encouraging findings indicate that polymeric amorphous solid dispersions could be a commercially feasible option to deliver poorly soluble drugs like NCL using HME.

Development of Lipid Polymer Hybrid Drug Delivery Systems Prepared by Hot-Melt Extrusion.

This study sought to develop polymer-lipid hybrid solid dispersions containing the poorly soluble drug lopinavir (LPV) by hot-melt extrusion (HME). Hence, the lipid and polymeric adjuvants were selected based on miscibility and compatibility studies. Film casting was used to assess the miscibility, whereas thermal, spectroscopic, and chromatographic analyses were employed to evaluate drug-excipient compatibility. Extrudates were obtained and characterized by physicochemical tests, including in vitro LPV dissolution. Preformulation studies led to select the most appropriate materials, i.e., the polymers PVPVA and Soluplus®, the plasticizers polyethylene glycol 400 and Kolliphor® HS15, phosphatidylcholine, and sodium taurodeoxycholate. HME processing did not result in LPV degradation and significantly increased entrapment efficiency (93.8% ± 2.8 for Soluplus® extrudate against 19.8% ± 0.5 of the respective physical mixture). LPV dissolution was also increased from the extrudates compared to the corresponding physical mixtures (p < 0.05). The dissolution improvement was considerably greater for the Soluplus®-based formulation (24.3 and 2.8-fold higher than pure LPV and PVPVA-based extrudate after 120 min, respectively), which can be attributed to the more pronounced effects of HME processing on the average size and LPV solid-state properties in the Soluplus® extrudates. Transmission electron microscopy and chemical microanalysis suggested that the polymer-lipid interactions in Soluplus®-based formulation depended on thermal processing.

Interfacial interactions in urease/stearic acid and urease/DOPC binary mixed systems at the air-water and the air-solid interfaces

In the present study, the protein-lipid interactions between water-soluble metalloenzyme urease (Urs) and insoluble stearic acid (SA) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were investigated at the air–water interface using the Langmuir-Blodgett (LB) technique. Surface pressure (π) - molecular area (A) isotherms were measured for the pure SA and pure DOPC monolayers in the presence of urease in the water subphase. From the (π – A) isotherms of the binary system, it was found that urease strongly interacts with SA and DOPC. The compressibility of the SA monolayer was reduced with the incorporation of urease; a similar trend was also found with DOPC. Moreover, an association of urease with lipid monolayers was found to be surface pressure (π) dependent. The presence of a little hump in the mixed isotherms of Urs-SA at low surface pressure supports this observation. However, the miscibility studies and the calculations of excess Gibb’s free energy indicate an attractive interaction between urease and SA molecules. The considerable morphological variations observed by atomic force microscopy (AFM) in urease-SA deposited films onto hydrophilic and hydrophobic Si(100) surfaces suggest that urease was strongly bound with the surrounding lipid SA on the hydrophilic surfaces but the urease molecules were rigorously denatured on the hydrophobic surfaces. The AFM analysis of Urs-DOPC mixed LB films at room temperature (RT) and elevated temperature suggests substantial denaturation of urease in a hydrophobic environment leading us to speculate the exposure of tryptophan moieties of the urease molecules to the hydrophobic air phase.

Solubility, miscibility and compatibility studies of low GWP non-flammable refrigerants and lubricants for refrigeration and air conditioning applications

Majority of currently used refrigeration and air conditioning systems utilize high GWP refrigerants such as R410A, R404A and R134a. These systems have large leak rates which leads to significant amount of release of HFC's to the environment. The growing environmental concerns are driving stringent regulations to phase out these high GWP refrigerants and move towards adoption of lower GWP refrigerants. This transition would require understanding of interaction between low GWP refrigerants and lubricating oil as well as the material compatibility with commonly used thermoplastics and elastomers. In this article, nonflammable low GWP refrigerants, R515B and R471A are introduced as the potential replacements for R410A, R404A and R134a in an air-conditioning and medium temperature refrigeration applications. Solubility and miscibility of R515B and R471A with polyol ester-based oil (POE32) is experimentally investigated over a temperature range of −20 °C to 120 °C and −30 °C to 75 °C, respectively. Further this article also presents the compatibility results of R515B and R471A (POE32) with thermoplastics and elastomers used in refrigeration and air-conditioning systems.

Induction of the Orthogonal Smectic A Phase in Mixtures of Nematic Tolanes with Positive and Negative Dielectric Anisotropy

Induction of the orthogonal smectic A phase occurs in mixtures of nematic compounds with positive and negative dielectric anisotropy. The aim of this work is to determine influence of a molecular structure of compounds on the induction strength of this phase. Cyclohexyl tolanes with the terminal group OCF3, differing with a lateral substitution of a rigid core with fluorine atoms, were mixed with tolanes with two fluorine atoms in a lateral position and different lengths of a terminal alkoxy chain. Based on phase diagrams, obtained with the use of a polarising optical microscope, the influence of a structure of both types of compounds on the induction of the SmA phase is presented. Both, an increase in a number of fluorine atoms in a rigid core and a decrease in an alkoxy chain length cause a decrease in the strength of the SmA phase induction in the investigated systems.Keywords: chemistry, liquid crystals, smectic A phase induction, miscibility studies

Ionic Liquids as Additives to Improve the Stretchability of Fluorine Rubber/Metal Filler Conductive Elastomers: a Miscibility Study

Ionic Liquids as Additives to Improve the Stretchability of Fluorine Rubber/Metal Filler Conductive Elastomers: a Miscibility Study

New Development in Understanding Drug-Polymer Interactions in Pharmaceutical Amorphous Solid Dispersions from Solid-State Nuclear Magnetic Resonance.

Pharmaceutical amorphous solid dispersions (ASDs) represent a widely used technology to increase the bioavailability of active pharmaceutical ingredients (APIs). ASDs are based on an amorphous API dispersed in a polymer, and their stability is driven by the presence of strong intermolecular interactions between these two species (e.g., hydrogen bond, electrostatic interactions, etc.). The understanding of these interactions at the atomic level is therefore crucial, and solid-state nuclear magnetic resonance (NMR) has demonstrated itself as a very powerful technique for probing API-polymer interactions. Other reviews have also reported exciting approaches to study the structures and dynamic properties of ASDs and largely focused on the study of API-polymer miscibility and on the identification of API-polymer interactions. Considering the increased use of NMR in the field, the aim of this Review is to specifically highlight recent experimental strategies used to identify API-polymer interactions and report promising recent examples using one-dimensional (1D) and two-dimensional (2D) experiments by exploiting the following emerging approaches of very-high magnetic field and ultrafast magic angle spinning (MAS). A range of different ASDs spanning APIs and polymers with varied structural motifs is targeted to illustrate new ways to understand the mechanism of stability of ASDs to enable the design of new dispersions.

Interfacial Behavior of Modified Nicotinic Acid as Conventional/Gemini Surfactants.

We report the synthesis and monolayer properties of conventional and gemini surfactants composed of nicotinic acid-based head groups with an emphasis on assessing how chemical structures affect the behavior of monolayers. A combination of Brewster angle microscopy and atomic force microscopy showed that pure hexadecyl nicotinate formed rippled strands in monolayers, and the gemini correspondents with either flexible or rigid organic linkers resulted in lobed-compact domains, which provides a simple method for patterning air-water and solid-air interfaces. The structural differences between conventional and gemini nicotinic acid-based surfactants could be explained by the interplay between line tension (that favors the formation of circular domains), balanced by dipole-dipole repulsion interaction between headgroups, which promotes extended domains. Miscibility and morphology studies of the modified nicotinic acid surfactants with palmitic acid demonstrated that the properties of mixed films can be controlled by the structure of the former. Excess Gibbs free energies of mixing indicated that the mixed films were less stable than the pure monolayers, and the positive deviations from ideality were the largest in the case of gemini surfactants.

Miscibility study of thermoplastic starch/polylactic acid blends: Thermal and superficial properties

In this work, the miscibility of blends of thermoplastic Achira Starch (AS) and polylactic acid (PLA) was evaluated, assisted by Pluronic® F127 an amphiphilic triblock copolymer that acts as a surfactant and promotes the reduction of surface tension among AS and PLA in solution by emulsion stabilization. Different formulations of AS/PLA blends were obtained at 75:25, 50:50, and 25:75 containing 0 %, 4 %, and 8 % of Pluronic® F127, and glycerol was used as a plasticizer. Solvent casting was the method used to obtain blended polymeric films, which were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), differential scanning calorimetry (DSC) and wettability by contact angle measurements. The results demonstrate that miscibility of PLA in AS or vice versa was achieved. The stability of emulsion and posterior drying of the different formulations allows the production of films for packaging, pharmaceutical, or biomedical applications.

New Method Based on Direct Analysis in Real-Time Coupled with Time-of-Flight Mass Spectrometry (DART-ToF-MS) for Investigation of the Miscibility of Polymer Blends.

The miscibility of a series of binary blends such as polystyrene/poly(methyl methacrylate) (PS/PMMA), polystyrene/poly(vinyl chloride)(PS/PVC), poly(vinyl chloride)/poly(polymethyl methacrylate)(PVC/PMMA) and poly(ethylene-co-vinyl alcohol)/poly(lactide-co-glycolide acid) PEVAL/PLGA with equal ratios and poly(ethylene oxide)/poly(hydroxyl propyl methyl cellulose) (PEO/PHPMC) containing 30 and 70 wt% PEO, which were randomly chosen among the widely systems reported in the literature, was investigated by a new method based on a direct analysis in real-time coupled with time-of-flight mass spectrometry (DART-ToF-MS). To reach this goal these pairs of polymers and copolymers were prepared by solvent casting method. As a first step, the DSC technique was undertaken in this work to highlight the published results on the miscibility of these binary systems. The thermogravimetry analysis (TGA) was used to define the optimum decomposition temperature of these blends programmed for the study of miscibility using the DART-ToF-MS technique. The results obtained by this method based on the comparison of the nature of the fragments resulting from the isothermal decomposition of the blend with those of their pure components have been very effective in demonstrating the character of miscibility of these systems. Indeed, it was found that the PS/PMMA-50 and PS/PVC-50 blends were immiscible, PVC/PMMA-50 and PEVAL/PLGA-50 miscible, and the PEO/PHMC partially miscible. This method, which is rapid and uses a very small amount of sample (1–2 mg) can be extended in its application to other blends whose other methods used have shown their limits due to the intrinsic properties of the polymers involved.

Exploration of Physicochemical Parameters of Natural Origin Polymers

Background: Natural polymers are fascinating category of small chain molecules originating from natural resources, and few examples include Sodium Alginate and Xanthan Gum which are water-soluble in nature; used for mainly food packaging, biomedical and pharmaceutical applications. In the proposed research work, an effort was made to overcome the polymer challenges emerging from the development of polymer blends, as the miscibility between polymers is a vital aspect. Objective: This work focuses on the miscibility studies of natural origin polymers. In regards to that, Sodium Alginate/ Xanthan Gum blends were prepared in variable concentrations in aqueous medium and it was utilized for viscosity analysis, FTIR, Ultraviolet spectroscopic studies at variable temperatures. Methods: It was observed that the developed Sodium Alginate / Xanthan Gum blends are miscible with each other at most of the temperatures (at 20°C, 40°C and 60°C) considering their viscosity parameters, FTIR and UV spectral data. Results: Viscosity studies revealed that the miscibility windows of polymeric ratio increases as the temperature increases whereas FTIR spectral patterns exhibited that the composition having 60:40 ratio of polymers exhibits high intensity stretches and represented to be miscible when compared to other combinations. Conclusion: The present study has reported the simple and efficient method in exploration of the miscibility windows of Sodium alginate and Xanthan gum blend.

Embedding an Amphiphilic 4-Hydroxy Thiazole Dye in Langmuir Matrices: Studying Miscibilities with Arylic and Alkylic Matrix Amphiphiles via Langmuir Isotherms and Photo-induced Force Microscopy.

We present here a fundamental study on the miscibility between a prototype amphiphilic dye and alkylic and arylic Langmuir monolayers. Embedding dyes in such matrices is crucial for utilizing dyes in any photo-energy conversion process if the involved dyes form aggregates that provide thermal deactivation channels. Because miscibility in Langmuir matrices depends on the blending ratio between the dye and matrix and on the Langmuir film density, as characterized via the surface pressure and the mean molecular area, we employ Langmuir miscibility studies to identify ideal miscibility parameters for each matrix. Atomic force microscopy (AFM) results support miscibility between the dye and both matrix materials at low surface pressures, where smooth and homogeneous films are obtained. AFM and photo-induced force microscopy (PiFM) reveal phase separation if the Langmuir monolayers are deposited at surface pressures above 8 mN/m at which reorientation of the chromophores has been reported. The nanoscale chemical fingerprint mapping enabled by PiFM enables assigning segregated spots to small stearic acid (SA)-enriched domains that have not been detected via AFM, thus demonstrating the value of the IR-spectroscopic contrast provided by PiFM. In this work, we have presented a so far unexploited matrix material (terphenylene carboxylic acid; TPCA) and found it equally suitable for embedding dyes as the standard amphiphile SA. In contrast to SA, TPCA is composed of rigid and electrically conducting π-electron systems, hence, being predestined for aligning dyes in Langmuir matrices and for application in optoelectronic systems.

Miscibility study of poly(ethylene oxide)/carboxymethyl cellulose blend

The present work deals with the miscibility study of poly (ethylene oxide) (PEO)/Sodium salt of carboxymethyl cellulose (Na-CMC) blend in aqueous medium using various methods like viscosity (η), refractive index (n), ultrasonic velocity (v) and density (ρ) at room temperature. Using viscosity data, Chee’s differential interaction parameters ‘ΔB’, ‘µ’ and Sun’s interaction parameter ‘α’ were computed. This study revealed that PEO/Na-CMC blend is found to be miscible when PEO content is greater than 50 wt%. In addition, the same was also studied by measuring the adiabatic compression (βad), acoustic impedance (z) and intermolecular free length (Lf) at room temperature. Further, the blend was used to prepare polymer blend films by solution cast technique. The blend films were then characterized using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) for their structural, thermal and morphological/microstructural studies respectively. The results of these studies were found to be in good agreement with the one obtained from the viscosity method.