Glycol Solution Research Articles

Temperature dependent micellization behavior of as synthesized anionic SAILs in aqueous nonionic polymer solutions: conductivity, UV-visible probe and antimicrobial studies

As synthesized surface active ionic liquids (SAILs), Tetrapropylammonium Dodecylsulfate (TPADS), and Tetrabutylammonium Dodecylsulfate (TBADS) have been characterized by FTIR, 1H-NMR and 13C-NMR spectroscopic techniques. Conductometric and UV-Visible probe investigations have been attempted to study the aggregation behavior of these synthesized SAILs in aqueous solution of polymers Polyvinylpyrrolidone (PVP) and Polyethylene glycol (PEG) at different temperatures and concentrations. Two breaking points were identified from κ vs [SAILs] plots. First, the critical aggregation concentration (CAC) is recognized with the polymer-SAILs binding and the second being regarded as critical micellar concentration (CMC), suggested to represent saturation point for Polymer-SAIL aggregation. Thermodynamic parameters of micellization ( Δ G m o , Δ H m o and Δ S m o ) are rationalized in terms of interactions prevailing between hydrophobic and hydrophilic regions of SAIL-Polymer system. Micellization process for the blend of SAIL-PVP is found to be more favored than SAIL-PEG at all temperatures. Further, the effect of PVP on the antimicrobial activities of TPADS/TBADS has been tested by measuring zone of inhibition which accounts for higher effectiveness of PVP-SAILs system against gram positive bacteria (Bacillus cereus and Staphylococcus aureus) as compared to gram negative bacteria (Pseudomonas aeruginosa).

Mass fabrication of Li2TiO3–Li4SiO4 ceramic pebbles with high strength by facile centrifugal granulation method

AbstractThe bi‐phase Li2TiO3–Li4SiO4 ceramic pebbles have been considered a promising breeder to realize the tritium self‐sustainment in the blanket. However, up to now, the reported ceramic pebbles have the disadvantages of low yield, poor crushing load, and loose internal structure, which cannot meet the practical application requirements. In this work, the Li2TiO3–Li4SiO4 ceramic pebbles with excellent mechanical properties were fabricated successfully via the centrifugal granulation method with the assistance of introducing a spray‐drying process, simulating particle trajectory by discrete element software and improving bonding interface between core and shell with ethylene glycol. The composition, microstructure, and inner structure of the Li2TiO3–Li4SiO4 ceramic pebbles were investigated, respectively, through X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and X‐ray computed tomography (CT). It can be found that the employment of the ethylene glycol solution on the surface of Li2TiO3 can make the core and the shell combine well. Moreover, the effect of the rolling speed of the Li2TiO3–Li4SiO4 ceramic pebbles was investigated via discrete element method (EDEM) simulation and experiments. The experimental results displayed that the Li2TiO3–Li4SiO4 ceramic pebbles sintered at 1100°C for 2 h have a uniform diameter of 1 mm, a good sphericity of 0.97, and an excellent crushing load of 82.4 N, which are superior to those pebbles that obtained by using the traditional wet methods. Moreover, the CT results showed that the appropriate porosity of the core was 3.21% and of the shell was 10.73%. Therefore, the simple centrifugal granulation method can be applied to prepare the Li2TiO3–Li4SiO4 ceramic pebbles in a large scale and shed a light to investigate the relevant advanced biphasic tritium breeder materials in the future.

Roles of hydrogen bonding interactions and hydrophobic effects on enhanced water structure strength in aqueous alcohol solutions

The structure and dynamics of water in aqueous alcohol solutions were explored using two-dimensional Raman correlation spectroscopy (2D Raman-COS) combined with the density functional theory (DFT). The spectral changes in the H–O–H bending and O:H stretching modes demonstrated that ethanol and n-propanol induced an enhancement of the water structure compared to methanol. The extent of this effect was related to the length of the alkyl chain. Comparative studies with aqueous ethylene glycol solution revealed that an enhanced water structure stemmed mainly from hydrophobic effects rather than hydrogen bonding (H-bonding) interactions. Alcohol-induced water-specific structural transitions were further analyzed using 2D Raman-COS, which showed that the free OH and strong H-bond structure of water respond preferentially to changes in alcohol content, inducing a transition in the weak H-bond structure of water. In addition, the 2D Raman-COS results indicated that the CH3 stretching mode of alcohol responds preferentially to variations in water content compared to other C–H vibrational modes. Finally, the details of the alcohol-induced water structural transitions were calculated using DFT. The 2D Raman-COS combined with DFT calculations provided insight into alcohol-induced water structural transitions and can be easily extended to other studies of water-organic chemistry.

A novel cascade glycolic acid pretreatment-alkali degumming method for producing hemp fiber

Hemp fiber is a promising textile resource. Because hemp fibers contain high gum content, an efficient degumming method needs to be developed. This study proposed a novel cascade degumming process coupling organosolv pretreatment and alkali boiling. Glycolic acid was optimally selected as a pretreatment reagent. The cascade process achieved a high lignin removal rate (69.81%) and hemicellulose removal rate (84.83%). The degummed hemp fibers showed excellent properties (4.18 ± 0.99 cN/dtex and 8.34 ± 0.01 dtex). Moreover, the glycolic acid solution could be reused three times without purification. The glycolic acid pretreatment led to decreased consumption of alkali reagents by 96.15%. Furthermore, the effect of glycolic acid pretreatment on lignin removal was analyzed by chemical composition analysis, FTIR, XRD, TGA, GPC, and HSQC NMR analysis. These results indicate that the novel cascade degumming process is an efficient and eco-friendly degumming method.

Hydrogen-Bond Dynamics and Water Structure in Aqueous Ethylene Glycol Solution via Two-Dimensional Raman Correlation Spectroscopy

The hydrogen-bond (H-bond) dynamics and water structural transitions in aqueous ethylene glycol (EG) solution were investigated on the basis of concentration- and temperature-dependent two-dimensional Raman correlation spectroscopy (2D Raman-COS). At room temperature, EG-induced enhancement of the water structure when the EG/water molar ratio is less than 1:28 resulted from the hydrophobic effect around the methylene groups of EG. The decrease in the temperature caused an enhancement of the Raman peak at about 3200 cm-1, representing an increase in the orderliness of water molecules. Further analysis of the water-specific structures by 2D Raman-COS reveals that the strong H-bond structure preferentially responds to external perturbations and induces a weak H-bond structural transition in water. Finally, EG-induced water structural transitions were calculated by the density functional theory (DFT). Hopefully, 2D Raman-COS combined with DFT calculations would advance the study of solute-induced water structural transitions in water-organic chemistry.

Anomalous behavior of liquid molecules near solid nanoparticles: Novel interpretation on thermal conductivity enhancement in nanofluids

HypothesisRecently, it has been reported that anomalous improvement in the thermal conductivity of nanofluid composed of base liquids and dispersed solid nanoparticles, compared to the theoretically predicted value calculated from the particle fraction. Generally, the thermal conductivity values of gases and liquids are dominated by the mean free path of the molecules during translational motion. Herein, we present solid evidence showing the possible contribution of the vibrational behavior of liquid molecules around nanoparticles to increasing these thermal conductivities. ExperimentsThe behavior of liquid molecules in nanofluids containing SiO2 particles larger than 100 nm, which were dispersed in a 50 wt% aqueous solution of ethylene glycol, was investigated by means of small-angle neutron scattering, quasi-elastic neutron scattering, wide-angle X-ray scattering, and Raman spectroscopy. FindingsThe vibrational changes in the liquid molecules caused by the interactions between the nanoparticles and liquid molecules surrounding the nanoparticles contributed majorly to the increase in the thermal conductivity values of the SiO2 nanofluids. Because the vibration of liquid molecules is equivalent to phonon conduction in solids, the increase in thermal conductivity of the suspension due to the presence of nanoparticles was inferred to be derived from the limitation of the translational diffusion, which induces a solid-like behavior in the liquid.

Unraveling the enthalpy of macromolecular crowding.

Concentrated solutions of synthetic polymers are often used to stabilize proteins, but there are few informed models that provide a detailed explanation of the effect. Classic crowding models are based on spherical, colloid-based solution theories, but such models only account for steric effects. To aid in the establishment of new, more informed, model, we acquired an extensive dataset that quantifies the effect of polyethylene glycol molecular weight and concentration on the temperature dependence of protein stability using 19F NMR. More specifically, we investigated the stability of the 7-kDa metastable N-terminal SH3 domain of Drosophila signal transduction protein drk (SH3) in polyethylene glycol solutions and quantified the modified standard-state free energy of unfolding and its enthalpic and entropic components. We used these data to build a new model which shows that interactions of solution components with both the folded and unfolded states must be considered. With this more nuanced understanding, we can better predict how polymers will affect the stability of protein-based drugs, how different biological molecules impact protein stability in cells and perhaps inform the design of even more useful stabilizing agents.

Instantaneous Formation of Silk Protein Aerosols and Fibers with a Portable Spray Device Under Ambient Conditions.

A variety of artificial silk spinning approaches have been attempted to mimic the natural spinning process found in silkworms and spiders, yet instantaneous silk fiber formation with hierarchical structure under physiological and ambient conditions without post-treatment procedures remains unaddressed. Here, we report a new strategy to fabricate silk protein-based aerosols and silk fibers instantaneously (< 1 s) in situ using a simple, portable, spray device, avoiding complicated and costly advanced manufacturing techniques. The key to success is the instantaneous conformational transition of silk fibroin from random coil to β-sheet right before spraying by mixing silk and polyethylene glycol (PEG) solutions in the spray device, allowing aerosols and silk fibers to be sprayed in situ, with further control achieved via the molecular weight of silk. The spinning process of the spray device is based on the use of green solvents, i.e., all steps of instant conformational transition of silk fibroin are carried out in aqueous conditions or with buffers at ambient conditions, in combination with shear and elongational flow caused by the hydraulic pressure generated in the spray container. The system supports a portable and user-friendly system that could be used for drug delivery carriers, wound coating materials and rapid silk fiber conformal coatings on surfaces.

Development of a multi-functional SPR sensing system using a square glass rod with two gold-deposited adjacent faces.

A multi-functional sensing system based on surface plasmon resonance (SPR) phenomenon using a square glass rod with two gold-deposited adjacent faces was developed in this work. This sensor system consists of a unpolarized light-emitting diode, a gold-deposited square glass rod, a polarizing beam splitter, and two photodiodes. The SPR responses of two adjacent faces are independently and simultaneously measured with a polarizing beam splitter and two PDs. The response property of the gold-deposited face was confirmed using methanol solutions of ethylene glycol. The response curve of the sensor of the 45nm gold-deposited face was compared with the theoretical curve calculated using multi-layer Fresnel equations. It was confirmed that the experimental curve is similar to the theoretical one. An evaluation was carried out on the square glass rod, which has an unmodified face and Teflon AF2400 coated gold-deposited face as multi-functional sensor. It was confirmed that this sensor can simultaneously measure the ethanol concentration in the glucose mix solution and refractive index of the sample from the calibration curve. Since this sensor can measure multiple components simultaneously, expected applications to various fields include medical diagnosis, food analysis, and environmental monitoring.

Phytochemical Compositions, Nutritional Contents, Cytotoxicity and Anti-Inflammatory Activity of Different Extracts from Spirogyra neglecta (Hassall) Kützing

Spirogyra neglecta (Hassall) Kützing is an edible freshwater macroalga. It is available and consumed as local food in Thailand, especially in the northern and northeastern parts. To ascertain its good benefit for health and safe for consumption, this study was, therefore carried out to determine the phytochemical compositions, nutritional contents, cytotoxicity, and anti-inflammatory activity of the different extracts from S. neglecta. The extracts were prepared by using different solvents, such as propylene glycol, methanol, and ethanol solutions. GC-MS analysis revealed the presence of 30, 39 and 36 phytochemical compounds in propylene glycol, methanol, and ethanol extracts, respectively. Phytol, which has been reported to have anti-inflammatory activity, was one of the predominant compositions in the extracts. The extracts contained high nutritional contents of protein, lipid, fiber, ash, moisture, and carbohydrate up to 21.68 ± 4.52, 3.53 ± 0.23, 14.77 ± 0.89, 10.73 ± 0.47, 9.79 ± 0.11 and 47.36 ± 3.89 %, respectively. The highest total protein was found in propylene glycol extract. The highest total lipid was in ethanol extract. Meanwhile, the highest fiber, ash and total carbohydrate were in methanol extract. In addition, all the extracts possess relatively low cytotoxicity, with IC50 values greater than 1,000 µg/mL. The extracts 1,000 µg/mL exhibited anti-inflammatory activity via inhibition Nitric oxide (NO) production by 29.87 ± 1.56 to 55.17 ± 1.91 %. The propylene glycol extracts from S. neglecta showed the highest inhibitory activity on NO production compared to others. The overall results indicating the propylene glycol is the solvent that produces the best extraction performance. The extracts from S. neglecta exhibit anti-inflammatory activity by inhibiting NO production. The phytochemical compositions are partly responsible for anti-inflammatory activity of the extracts. The high nutritional contents complement relatively low toxic. Thus, S. neglecta can be used as benefit natural sources for food products, supplements, and medicinal plants. HIGHLIGHTS Using GC-MS analysis, there are 30, 39 and 36 phytochemical compounds in propylene glycol, methanol and ethanol extracts from Spirogyra neglecta, respectively The extracts from neglecta possess high nutritional contents of protein, lipid, fiber, ash, moisture, and carbohydrate The extracts from neglecta show relatively low toxic to the RAW 246.7 cells with LC50 &gt;1,000 µg/mL, by MTT assay The extracts from neglecta exhibit anti-inflammatory activity by inhibition of NO production. The propylene glycol extract displays the highest activity compared to others The anti-inflammatory activity of the extracts is partially from Phytol GRAPHICAL ABSTRACT

Gauging DNA degradation among common insect trap preservatives

AbstractGenetic methods for species identification are becoming increasingly popular and can accelerate insect monitoring. However, obtaining good DNA quality and quantity from insect traps remains a challenge for field studies. Ethylene glycol, propylene glycol, and Renner solution have been previously suggested as suitable preservatives for the collection of genetic material, but a systematic overview of their performance under compromising field conditions is lacking. Here we experimentally test whether and how different preservatives affect DNA quality under different conditions and evaluate how choice of preservative may affect metabarcoding and more demanding downstream applications (e.g., RADseq). For this, we used the house cricket, Acheta domesticus (L.) (Orthoptera: Gryllidae), and tested propylene glycol, ethylene glycol, and Renner solution for their ability to preserve DNA over 27 days in various dilutions and temperatures. DNA quality was measured as DNA fragmentation and success rates in PCR amplifying a COI fragment of 658, 313, or 157 bp. Undiluted propylene glycol and ethylene glycol always retained high molecular weight DNA at room temperature. No high molecular weight DNA was preserved at 37 °C or in any dilution. Nevertheless, the COI sequence could be amplified from samples at every condition. Renner solution did not preserve high molecular weight DNA and fragmentation increased over time at 37 °C until amplification was impossible. The results suggest that propylene glycol and ethylene glycol are suitable preservatives for collecting both genetic and morphological material, but dilution or high temperatures compromise their ability to preserve high molecular weight DNA. For genomic approaches requiring high DNA quality, additional preservatives may need to be tested.

Comments Regarding “Volumetric, Acoustic, Viscometric Properties, and Solute–Solvent Interactions of Metformin Hydrochloride in Aqueous Solution of Polyethylene Glycol (PEG 4000) at Different Temperatures (T = 288.15–318.15 K)”

Comments Regarding “Volumetric, Acoustic, Viscometric Properties, and Solute–Solvent Interactions of Metformin Hydrochloride in Aqueous Solution of Polyethylene Glycol (PEG 4000) at Different Temperatures (T = 288.15–318.15 K)”

Modeling the influence of temperature, salt and osmotic stresses on seed germination and survival capacity of Stipa tenacissima L.

This work stands for a modelling approach to identify the cardinal temperature of germination of Stipa tenacissima L., its capacity to recover and its adaptation potential considering dormancy and viability after exposure to salinity and drought. Seed traits characterised before germination were tested. The seeds were incubated at temperatures of 10 to 30 °C and low osmotic potentials were induced using sodium chloride (NaCl) or polyethylene glycol (PEG 6000) solutions of 0 to −1.6 MPa. The capacity of seeds to recover and remain viable under stress conditions was quantified. Our results proved that the seed yields and sizes were uniform. The analysis of cardinal temperature by thermal time model exhibited an optimal germination temperature (T o) of about 19 °C, a base temperature (T b) of 0.6 °C and a ceiling temperature (T c) of 31 °C at 0 MPa. The base water potential Ψb (50) values ranged between −0.83 and −1.54 MPa and between −0.97 and −2.27 MPa for osmotic and salt stresses, at 30 °C and 20 °C, respectively. In conclusion, the species showed a lower seed recruitment related to a low drought tolerance (drought tolerance index = −0.5 MPa), To requirement and threshold sensitivity. Under salt stress, S. tenacissima used osmotic adjustment in order to germinate in a lower osmotic potential.

Pre-swelling of FAA3 membranes with water-based ethylene glycol solution to minimize dimensional changes after assembly into a water electrolyser: Effect on properties and performance

Stability of membranes in electrolysers is challenged by dimensional changes, when dry membranes are assembled and wetted when the electrolyser starts. Assembling wet membranes is challenging because water evaporates during handling. To minimize dimensional changes, FAA3 membranes are pre-swollen in aqueous ethylene glycol (EG, boiling point 197°C). Membranes partially dissolve in 100 vol% EG, and swell excessively in 70 vol%. Swelling in 50 vol% shows smallest dimensional changes during handling (shrink) and re-immersion in KOH solution (swelling, mimicking start of the electrolyser). These membranes show about 30% higher conductivity (ca. 65 mS cm−1). Tensile strength and Young’s Modulus decrease exponentially with the amount of absorbed EG solution, while elongation at break increases. In addition to the improved dimensional stability during handling, EG treated membranes perform better in the electrolyser than untreated membranes. In a stability test over 120 h at 250 mA/cm2, all membranes show an initial drop in the cell voltage and then stabilize.

The controllable synthesis of NiO/Ni/C nanosheets via pulsed plasma in ethylene glycol solution for oxygen evolution electrocatalysis.

NiO-based composites exhibit high catalytic activity for the oxygen evolution reaction (OER). Herein, high-performance NiO/Ni/C nanosheet catalysts were obtained by liquid-phase pulsed plasma (LPP), which was generated between two nickel electrodes in ethylene glycol (EG) solution by a homemade high-voltage pulse power supply. Melted nickel nanodrops were ejected from nickel electrodes which were bombarded by the energetic plasma. Simultaneously, high-temperature nickel nanodrops promoted the decomposition of the organics which were converted in the EG solution by the catalysis of LPP and formed hierarchical porous carbon nanosheets. Due to the high surface energy of the hierarchical porous carbon nanosheets, the spherical particles of Ni/NiO were adsorbed on the surface to compose the NiO/Ni/C composites. The pore size distribution of the composites could be controlled with different EG concentrations. When the EG concentration was 10 vol% (EG30), the composites possessed a H2 + H2 + H3 type pore size distribution and maximum active site area, leading to an exceptional OER activity (289.2 mV overpotential at 10 mA cm-2).

Selective photoelectrocatalytic oxidation of 3-methylpyridine to vitamin B3 by WO3 decorated nanotube-structured TiO2.

Nanotube-structured TiO2 electrodes on Ti plates were formed in ethylene glycol solution by the anodic oxidation method applied for different times and calcined at 500 °C. Different amounts of WO3 were decorated on the nanotube surfaces electrochemically. The electrodes were characterized, and the effects of the nanotube length on the Ti plate, decorated WO3 amount, electrolyte concentration, applied potential, and type of radiation source on the oxidation of 3-methylpyridine were investigated, together with the product distribution/selectivity. In a photoelectrocatalytic system, the vitamin B3 yield increased significantly (ca. 17 fold) under UVA by decorating nanotube-structured TiO2 with WO3, whilst low reaction rates and no products were found under Vis irradiation, as only unselective photolytic reactions occurred. This unexpected result was clarified for the first time in the literature.

Vapor-phase oxidation of propylene glycol-methanol mixture to methyl lactate on CeO2/Al2O3 catalyst

The vapor-phase oxidation of mixtures of propylene glycol with methanol and ethanol to methyl and ethyl lactate, respectively, on supported CeO2/Al2O3 catalyst at 210-2500С was investigated. Air oxygen and a flow reactor with a fixed catalyst bed were used. A 20% solution of propylene glycol in alcohol was supplied to the reactor inlet. Oxidation of propylene glycol in the presence of methanol occurs according to the overall reaction CH3CHOHCH2OH +O2 + СН3OH = CH3CHOHCOOСН3 +2H2O. First, hydroxyacetone is formed, which is further oxidized to pyruvic aldehyde, which adds alcohol to form a hemiacetal. Next, this hemiacetal is rearranged according to Cannizzaro into methyl lactate. At 2200C and catalyst load &lt; 2 mmol PG/gcat/h, the selectivity for methyl lactate reached 70 wt.% at 100% propylene glycol conversion. In the presence of ethanol, the formation of a significant amount of acetaldehyde and its aldol condensation products, as well as the formation of diethoxyethane, was observed. Therefore, the selectivity for ethyl lactate at 100% propylene glycol conversion did not exceed 45%.

Mid‐infrared spectroscopy study of aqueous solution of ethylene glycol using chemometrics analysis and two‐dimensional correlation spectroscopy

Abstract1, 2‐Ethandiol (ethylene glycol, EG) and its mixtures with water (W) have widespread industrial and biological applications due to their special physiochemical properties. In this study, two‐dimensional correlation spectroscopy and chemometrics analysis of infrared spectra are used to characterize structural features of EG–W binary solutions. Three distinctive regions are observed with diverse contributions of hydrophobic backbone (CH2 groups) and hydrophilic (OH functional) groups. Both groups are simultaneously considered to characterize local structure in each triple region. The aqueous solutions of EG are changed from EG‐like (xw ≤ 0.27) to W‐like solution (xw &gt; 0.83), where xw is W mole fraction. The wide range of EG–W mixtures (0.27 &lt; xw ≤ 0.83) are stabilized by –OH … O (proper hydrogen bonded) and –CH … O (improper hydrogen bonded). Also, trend and relative equilibrium concentration variation of W, EG, and identified cluster are used to propose chemical model of EG–W interaction.

Comparison of the Efficacy of Diluted Polyethylene Glycol and Low-Density (0.1% w/v) Barium Sulfate Suspension for CT Enterography.

To compare small bowel distension and side effects between a diluted polyethylene glycol (PEG) solution and a low-density (0.1% w/v) barium sulfate suspension (LDBSS) for CT enterography (CTE) preparation. Total 173 consecutive patients who underwent CTE were enrolled in this study. The LDBSS (1 L) was used in 50 patients, and the diluted iso-osmotic PEG solution (1 L) was used in 123 patients. Two blinded radiologists independently scored jejunal and ileal distensions on a 5-point scale. To compare side effects between the two groups, the patients reported whether they had immediate complications after the administration of the oral contrast media. For ileal and jejunal distension, the diluted PEG solution showed no difference from the LDBSS for either reader (ileum: reader 1, median, 4; 4, interquartile range, 3-4; 3-4, p = 0.997; reader 2, median, 4; 4, interquartile range, 3.3-4.0; 3-4, p = 0.064; jejunum: reader 1, median, 2; 2, interquartile range, 2-3; 2-3, p = 0.560; reader 2, median, 3; 2, interquartile range, 2-3; 2-3, p = 0.192). None of the patients complained of immediate complications following administration of either of the oral contrast media. The diluted PEG solution showed comparable bowel distension compared to LDBSS and no immediate side effects; thus, it can be a useful alternative.

Ethylene glycol energetically disfavours oligomerization of pseudoisocyanine dyestuffs at crowded concentrations.

The intriguing role of the intracellular crowded environment in regulating protein aggregation remains elusive. The convolution of several factors such as the protein sequence-dependence, crowder's shape and size and diverse intermolecular interactions makes it complex to identify systematic trends. One of the ways to simplify the problem is to study a synthetic model for self-assembling proteins. In this study, we examine the aggregation behaviour of the cationic pseudoisocyanine chloride (PIC) dyestuff which is known to self-assemble and form fibril-like J-aggregates in aqueous solutions, similar to those formed by amyloid-forming proteins. Prior experimental studies have shown that polyethylene glycol impedes and Ficoll-400 promotes the self-assembly of PIC dyes. To achieve molecular insights, we examine the effect of crowding by ethylene glycol on the solvation thermodynamics of oligomerization of dyes into H-type and J-type oligomers using extensive molecular dynamics simulations. The binding free energy calculations show that the formation of J-oligomers is more favourable than that of H-oligomers in water. The stability of H- and J- tetramers and pentamers decreases in crowded solutions. The formation of oligomers is supported by the favourable change in dye-solvent interaction energy in both pure water and aqueous ethylene glycol solution although it is opposed by the reduced dye-solvent entropy. Ethylene glycol, as a molecular crowder, disfavours the H- as well as J-oligomerization via preferential binding to the dye oligomers. An unfavourable change in dye-crowder and dye-dye interaction energy on dye association makes the H-oligomer formation less favourable in crowded solution than in pure water solution. In the case of J-oligomers, however, the unfavourable change in dye-crowder interaction energy primarily contributes to making total dye-solvent energy unfavourable. The results are supported by isothermal titration calorimetry measurements where the binding of ethylene glycol to PIC molecules is found to be endothermic. The results provide an emerging view that a crowded environment can disfavour self-assembly of PIC dyes by interactions with the oligomeric states. The findings have implications in understanding the role of a crowded environment in shaping the free energy landscapes of proteins.