Elastic Gel Research Articles

Rheology, Texture and Swallowing Characteristics of a Texture-Modified Dysphagia Food Prepared Using Common Supplementary Materials.

A dysphagia diet is a special eating plan. The development and design of dysphagia foods should consider both swallowing safety and food nutritional qualities. In this study, the effects of four food supplements, namely vitamins, minerals, salt and sugar, on swallowing characteristics, rheological and textural properties were investigated, and a sensory evaluation of dysphagia foods made with rice starch, perilla seed oil and whey isolate protein was carried out. The results showed that all the samples belonged to foods at level 4 (pureed) in The International Dysphagia Diet Standardization Initiative (IDDSI) framework, and exhibited shear thinning behavior, which is favorable for dysphagia patients. Rheological tests showed that the viscosity of a food bolus was increased with salt and sugar (SS), while it decreased with vitamins and minerals (VM) at shear rates of 50 s-1. Both SS and VM strengthened the elastic gel system, and SS enhanced the storage modulus and loss modulus. VM increased the hardness, gumminess, chewiness and color richness, but left small residues on the spoon. SS provided better water-holding, chewiness and resilience by influencing the way molecules were connected, promoting swallowing safety. SS brought a better taste to the food bolus. Dysphagia foods with both VM and 0.5% SS had the best sensory evaluation score. This study may provide a theoretical foundation for the creation and design of new dysphagia nutritional food products.

Physico-chemical and rheological properties of meat pates with corn starch suspensions prepared on electrochemically activated water

Introduction. The aim of the study was to determine the influence of electrochemically activated water application on the rheological properties of corn starch suspensions and pates prepared with them. Materials and methods. Corn starch suspensions were prepared on artesian water, which was activated by electrochemical treatment on a diaphragm electrolyzer. Physico-chemical characteristics of electrochemically activated water were determined using a Palintest 7500 photometer. Morphological studies of starch granules were carried out by scanning electron microscopy, and granulometric composition was determined by laser diffraction method. The rheological indicatorss of starch suspensions and pates were studied using a Kinexus Pro+ rheometer. Results and discussion. The physico-chemical characteristics of electrochemically activated water except pH met the requirements of the European Parliament and Council Directive on the quality of water intended for human consumption. The water absorption capacity of starch when preparing its suspensions on a catholyte (obtained by passing a direct electric current through water in the cathode chamber of an electrolyzer) decreased by 26%, and when prepared on an anolyte (obtained in the process of water oxidation reactions on the anode) increased by 18%. The moisture holding capacity of hydrated starch decreased by 10% when using catholyte, and increased by 36% when using anolyte. Electrochemically activated water had a significant effect on the rheological characteristics of starch suspensions: with an increase in the percentage of complex shear strain, the shear stress increased proportionally for samples of suspensions made on electrochemically activated water. The viscoelastic properties of starch suspensions prepared using electrochemically activated water both at 25 ℃ and at 68 ℃ tended towards an ideally elastic gel, that is, they had more elastic structure than the control samples. Under the action of shear deformation, the elastic properties were lost, while the suspensions acquired viscosity (phase angle values increased). The maximum value of the moisture binding capacity of pates was observed when using a starch suspension prepared on anolyte. The best values of rheological characteristics of pates were obtained when using starch suspension with 2% starch prepared on anolyte. Conclusions. Electrochemically activated water had a significant effect on the physicochemical and rheological properties of semi-finished products, in particular corn starch suspensions, and pates prepared with them, and contributed to better structuring of the studied food systems.

Structural and shear and extensional rheological properties of hairy basil seed mucilage for potential application as oropharyngeal dysphagia diets

In this study, mucilage was extracted from the swollen hairy basil (Ocimum × africanum Lour.) seeds using ultrasonic-assisted extraction. Clear mucilage (BSM) was subsequently obtained by centrifugation for studies on its structural and shear and extensional rheological properties. The results revealed that the extracted BSM was rich in galactose and xylose, but low in mannose and galacturonic acid contents which indicated the presence of arabinogalactan and xylan. Small amounts of proteins (∼5%) were also detected. The average molecular weight of BSM was estimated as ∼480 kDa. Shear rheology results showed that aqueous dispersions of BSM at 1.0–2.5%w/v exhibited solid-like viscoelastic behavior with small frequency dependency, resembling a cross-linked gel. All BSM samples also exhibited shear thinning behavior that could be described by the power law model. However, the Cox-Merz rule was not obeyed for all studied BSM gels. The gel's elasticity was enhanced with increasing BSM concentration. For extensional rheology, the apparent extensional viscosity showed an extensional strain-softening behavior and demonstrated higher filament breakup time and extensional viscosity with increasing BSM concentration. A comparison between BSM and commercial thickening agents widely used in dysphagia management showed comparable rheological characteristics, thus suggesting the promising potential of BSM as a thickening agent for this application.

The hidden hierarchical nature of soft particulate gels

Soft particulate gels are composed of a small amount of particulate matter dispersed in a continuous fluid phase. The solid components assemble to form a porous matrix, providing rigidity and control of the mechanical response, despite being the minority constituent. The rheological response and gel elasticity are direct functions of the particle volume fraction. However, the diverse range of different functional dependencies reported experimentally has challenged efforts to identify general scaling laws. Here we reveal a hidden hierarchical organization of fractal elements that controls the viscoelastic spectrum, and which is associated with the spatial heterogeneity of the solid matrix topology. The fractal elements form the foundations of a viscoelastic master curve, constructed using large-scale three-dimensional (3D) microscopic simulations of model gels, which can be described by a recursive rheological ladder model over a range of particle volume fractions and gelation rates. The hierarchy of the fractal elements provides the missing general framework required to predict the gel elasticity and the linear viscoelastic response of these complex materials. Colloidal gels consist of particles embedded in a fluid. It is now found that a gel’s viscoelastic spectrum, relating mechanical properties and deformation frequencies, can be understood by modelling these gels as networks of fractal viscoelastic units, connected hierarchically.

Physicochemical properties of wooden breast-extracted myosin and rheological properties of its heat-induced gel.

It is reported that broilers with 'wooden breast' have poor processing properties, such as low binding and water-holding capacities. However, the reason for the poor functional characteristics has not been clarified. In this study, myosin was extracted from a wooden breast. Its physicochemical properties were investigated to clarify the relationship between the structure and physicochemical properties of the heating gel of myosin obtained from the wooden breast. The turbidity of myosin solution extracted from wooden breast increased with increase in the heat treatment to a higher value than that from the normal breast meat myosin. The solubility of myosin collected from a wooden breast after heating decreased like normal breast muscle myosin. The surface hydrophobicity of myosin removed from wooden breast increased continually above 60 °C, unlike the change in surface hydrophobicity of normal breast myosin. The free thiol group of myosin extracted from the wooden breast was higher than normal breast myosin before and after heating. The apparent elasticity of heat-induced gels and chicken meat sausages was significantly lower in sausages and gel with wooden breast than normal ones (P < 0.05). The microstructure of the heated gel of normal myosin showed a fine network structure. In contrast, the heat-induced gel of wooden breast-extracted myosin showed a structure with loosely connected aggregates and many gaps. The coarseness of the internal gel structure of myosin extracted from wooden breast was shown to affect the apparent elasticity of the gel and sausages made from the chicken meat. © 2023 Society of Chemical Industry.

Effect of Cold Atmospheric Pressure Argon Plasma Jet Treatment on the Freeze-Dried Mucilage of Chia Seeds (Salvia hispanica L.).

In the present study, the effects of the treatment of chia seeds with a cold atmospheric pressure plasma jet (CP) using argon as a working gas for different times (30, 60, and 120 s) on the rheological, structural, and microstructural properties of the freeze-dried mucilages at -54 °C were investigated. All mucilage gels showed pseudoplastic flow behavior, and CP treatment of chia seeds increased the viscosity of mucilages, probably due to the cross-linking between polymer molecules. The dynamic rheological analysis revealed that all mucilages were elastic gels and that CP treatment improved the elastic properties in a treatment time-dependent manner. Large amplitude oscillatory shear (LAOS) results showed that freeze-dried mucilages showed Type I strain-thinning behavior. Similar to small amplitude oscillatory shear (SAOS) results, CP treatment has affected and improved the large deformation behavior of mucilages depending on treatment time. Meanwhile, Fourier transform infrared spectroscopy (FTIR) revealed the incorporation of hydroxyl groups onto the surface and the formation of C-O-C glycosidic bonds during plasma treatment. Scanning electron microscope (SEM) micrographs showed the formation of denser structures with CP treatment time. Regarding color properties, CP treatment decreased the lightness values of mucilages. Overall, this study showed that CP is an effective way to modify both the SAOS and LAOS properties of freeze-dried chia mucilage and improve viscosity.

Thermorheological Behavior of κ-Carrageenan Hydrogels Modified with Xanthan Gum

Hydrocolloids are long-chain biopolymers that can form viscous solutions or gels when dissolved in water. They are employed as rheological modifiers in various manufacturing processes or finished products. Due to its unique gelation properties, animal gelatin is one of the most widely used hydrocolloids, finding applications in several fields such as food, pharmaceutical, and photographic. Nowadays, the challenge of finding valid alternatives to animal products has become a crucial issue, for both ethical and environmental reasons. The aim of this work, is to propose a green hydrocolloidal network, able to reproduce the gelation features of animal gelatin gels. κ-carrageenan gels may be an interesting alternative to gelatin, due to their attractive gelling features. We investigate the thermorheological behavior of κ-carrageenan aqueous solutions at various concentrations, focusing on gel features such as transition temperature and gel strength. To improve the viscoelastic response of such gels, we add a viscosity-enhancing hydrocolloid, i.e., xanthan gum. The results show that the gel strength increases exponentially with xanthan concentration, thus suggesting a synergistic interaction between the two networks. We also study the effect of sucrose on the thermal and mechanical properties of modified gels, finding a marked increase in transition temperatures and gel elasticity. In recent years, three-dimensional (3D) food printing has been extensively studied in the food industry, due to its many advantages, such as customized food design, personalized nutrition, simplified supply chain, and the expansion of available food materials. In view of this growing interest for additive manufacturing, we also study the printability of the complete formulation composed of κ-carrageenan, xanthan gum and sucrose.

Differential contractility regulates cancer stem cell migration

Cancer stem cells (CSCs) are known to have a high capacity for tumor initiation and the formation of metastases. We have previously shown that in collagen constructs mimetic of aligned extracellular matrix architectures observed in carcinomas, breast CSCs demonstrate enhanced directional and total motility compared with more differentiated carcinoma populations. Here, we show that CSCs maintain increased motility in diverse environments including on 2D elastic polyacrylamide gels of various stiffness, 3D randomly oriented collagen matrices, and ectopic cerebral slices representative of a common metastatic site. A consistent twofold increase of CSC motility across platforms suggests a general shift in cell migration mechanics between well-differentiated carcinoma cells and their stem-like counterparts. To further elucidate the source of differences in migration, we demonstrate that CSCs are less contractile than the whole population (WP) and develop fewer and smaller focal adhesions and show that enhanced CSC migration can be tuned via contractile forces. The WP can be shifted to a CSC-like migratory phenotype using partial myosin II inhibition. Inversely, CSCs can be shifted to a less migratory WP-like phenotype using microtubule-destabilizing drugs that increase contractility or by directly enhancing contractile forces. This work begins to reveal the mechanistic differences driving CSC migration and raises important implications regarding the potentially disparate effects of microtubule-targeting agents on the motility of different cell populations.

Formulasi Sistem Vesikel Elastik Surfaktan Nonionik Ekstrak Etanol Rimpang Etlingera alba dalam Sediaan Gel

Etlingera alba is a plant in Southeast Sulawesi that has antioxidant activity. Natural ingredients such as herbal medicine require a delivery system that facilitates them to reach the site of drug action, especially for transdermal delivery. The elastic vesicle system is a transdermal delivery system that can increase the penetration of active substances at the skin through the act of phospholipids on the skin's lipid bilayer and the deformability of the vesicles. This study aims to formulate and evaluate Etlingera alba rhizome ethanolic extract's elastic vesicle gel to obtain the optimal concentration of Tween 60 as a vesicle former and carbopol as a gel base. Preparation of elastic vesicles of Etlingera alba ethanolic extract using the heat method through variations Tween 60's concentration, namely 5%(F1); 10%(F2); 15%(F3); and 20%(F4). Meanwhile, elastic vesicle gel formulation of the ethanol extract of Etlingera alba rhizome used various concentrations of 0.5% carbopol gel base (FGel 1); 1% (FGel 2); 1.5% (FGel 3); and 2% (FGel 4). The results obtained were the optimum concentration of Tween 60 as a constituent of elastic vesicles of 15% (F4) with spherical morphology using an optical microscope, vesicle size of 10.45 nm, and polydispersity index of 0.280 using a Particle Size Analyzer. In addition, the optimal concentration of carbopol as a base for elastic vesicle gel is a concentration of 0.5% (GGel 1) with white color, distinctive aroma, and thick texture, and has a pH of 6, a viscosity of 2,366 cPs, spread of 6.8 cm, and physically stable through cycling test.

Effects of divalent mercury on myosin structure of large yellow croaker and its binding mechanism: Multi-spectroscopies and molecular docking

Heavy metals have long biological half-lives and are therefore a major threat to aquatic organisms, especially fish. Divalent mercury (Hg(II)) is an important form from a toxicological viewpoint. In this paper, we studied the interaction mechanism between large yellow croaker myosin and Hg(II) by multi-spectroscopies and molecular docking. Hg(II) had a positive effect on improving the elasticity of myosin gel, and the constant increase of charge would destroy the gel. Hg(II) caused myosin to aggregate, and the protein's apparent structure rapidly increased in length. The content of α-helix obviously decreased, β-turns and β-sheet increased. The myosin and Hg(II) quenching type was static quenching. Thermodynamic analysis suggested hydrogen bonding and van der Waals forces were the main forces for the combination. The molecular docking further confirmed the mechanism of action. This study provides a theoretical guidance for the preventions and control of marine heavy metals.

Physicochemical properties, structural characteristics and in vitro digestion of brown rice–pea protein isolate blend treated by microbial transglutaminase

The present study sought to use microbial transglutaminase (MTG) to modulate the physicochemical properties of brown rice protein isolate (BRPI), pea protein isolate (PPI) and their blend, and determine MTG's effect on protein structural and digestive profile changes. MTG at concentration of 1 U/g significantly increased water holding capacity (91.6% enhancement) and decreased oil holding capacity (39.3% reduction) of BRPI + PPI (4:6) blend, respectively, accompanied by decreasing their solubility and zeta potential values in aqueous system. From rheological analysis, MTG-induced crosslinks could result in stronger and more elastic gels in BRPI + PPI blend with lower gel point temperature. SDS-PAGE demonstrated that the number and intensities of the protein bands for all MTG-treated BRPI were similar under both non-reducing and reducing conditions, whereas in the samples containing PPI, fewer and fainter bands were shown in the groups treated by MTG at concentration of 4 U/g and above. From FTIR spectra, lower level of random coils paralleled by an increase in both β-sheet structures and α-helix band were observed in the 1.0 U/g MTG-treated BRPI + PPI blend, indicating the protein-protein interactions within the mixed systems might boost the role of MTG in the structural modification, facilitating the network formation of more ordered structure with better thermal stability. Results of in vitro digestion showed less hydrophobic amino acids and essential amino acids including Lys released in MTG-treated BRPI + PPI blend's digests. Overall, the application of MTG in plant-based proteins can potentially contribute to the development of innovative food products with modified functionalities and unique digestive characteristics.

The Role of Amylose in Gel Forming of Rice Flour.

In this study, Glutinous rice (GR), Japonica rice (JR), and Indica rice (IR), with amylose contents at 1.57 ± 0.18%, 15.88 ± 1.16%, and 26.14 ± 0.25%, respectively, were selected to reveal the role of amylose in the gel forming of rice flours. The strength and elasticity of the associated gels were found in an ascendant order with the increase in amylose content. For the retrograded gels (at 4 °C for 7 days), the peak temperature (Trp) was positively related to the amylose content. In general, Trp of IR increased to 63.21 ± 0.13 °C, and the relative crystallinities of IR were in the top ranking at 10.67 ± 0.16%, followed by those of JR and GR. The relative amounts of short-range ordered structures to amorphous regions in JR and IR were also higher than that of GR, and the number of compact network structure were positively related to the amylose content. These results indicated that amylose can enhance the strength and elasticity of gels by facilitating the formation of crystalline, short-range ordered, and compact network structures. These results can provide a reference for the development of rice products.

Three length-scales colloidal gels: The clusters of clusters versus the interpenetrating clusters approach

Typically, in quiescent conditions, attractive colloids at low volume fractions form fractal gels structured into two length scales: the colloidal and the fractal cluster scales. However, when flow interferes with gelation colloidal fractal gels, it may display three distinct length scales [Dagès et al., Soft Matter 18, 6645–6659 (2022)]. Following those recent experimental investigations, we derive two models that account for the structure and the rheological properties of such atypical colloidal gels. The gel elasticity is inferred from scaling arguments, and the structure is translated into scattering intensities following the global scattering functions approach proposed by Beaucage and, typically, measured in small-angle x-ray scattering (SAXS). In both models, we consider that the colloids condensate into fractal clusters. In the clusters of the clusters model, the clusters form superagregates that then build the gel network. In the interpenetrating clusters model, the clusters interpenetrate one another to form the gel network. Those two models are then used to analyze rheo-SAXS experiments carried out on carbon black gels formed through flow cessation.

Gel properties of rice varieties in relation to bread baking potential

ABSTRACT The properties of rice flour gel relative to yeast-leavened bread baking potential have been investigated. Twelve rice varieties were dry-milled to flour. Firm gels with a jelly-like consistency, only formed in high and intermediate amylose content (AC) varieties, including Goamibyeo, Milyang260, Suweon517, and Milyang261. These varieties maintained their shape after baking, yielding bread volumes comparable to that of wheat bread. Eight low AC varieties that did not form hard gels were unsuitable for bread-making due to shrinkage during cooling. Specific bread volumes correlated positively (p < .01) with gel hardness, elasticity, and cohesiveness. Crumb firmness correlated negatively (p < .01) with gel hardness and elasticity. Gel fracturability also correlated (p = .015) with crumb firmness. Hard gel formation was the primary determinant of rice suitability for yeast-leavened bread. Secondarily, the gel should be elastic and non-brittle. The physical properties of rice flour gels can be useful for predicting rice flour bread-making potential.

Phase behavior of medium-length hydrophobically associating PEO-PPO multiblock copolymers in aqueous media

HypothesisThe micellization of block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) is driven by the dehydration of PPO at elevated temperatures. At low concentrations, a viscous solution of isolated micelles is obtained, whereas at higher concentrations, crowding of micelles results in an elastic gel. Alternating PEO-PPO multiblock copolymers are expected to exhibit different phase behavior, with altered phase boundaries and thermodynamics, as compared to PEO-PPO-PEO triblock copolymers (Pluronics®) with equal hydrophobicity, thereby proving the pivotal role of copolymer architecture and molecular weight. ExperimentsMultiple characterization techniques were used to map the phase behavior as a function of temperature and concentration of PEO-PPO multiblock copolymers (ExpertGel®) in aqueous solution. These techniques include shear rheology, differential and adiabatic scanning calorimetry, isothermal titration calorimetry and light transmittance. The micellar size and topology were studied by dynamic light scattering. FindingsMultiblocks have lower transition temperatures and higher thermodynamic driving forces for micellization as compared to triblocks due to the presence of more than one PPO block per chain. With increasing concentration, the multiblock copolymers in solution gradually evolve into a viscoelastic network formed by soluble bridges in between micellar nodes, whereas hairy triblock micelles jam into liquid crystalline phases resembling an elastic colloidal crystal.

Touchable Gustation via a Hoffmeister Gel Iontronic Sensor

A particular sense, touchable gustation, was achieved. We proposed a chemical-mechanical interface strategy with an iontronic sensor device. A conductive hydrogel, amino trimethylene phosphonic acid (ATMP) assisted poly(vinyl alcohol) (PVA), was employed as the dielectric layer of the gel iontronic sensor. The Hofmeister effect of the ATMP-PVA hydrogel was well investigated to establish the quantitative description of the gel elasticity modulus to chemical cosolvents. The mechanical properties of hydrogels can be transduced extensively and reversibly by regulating the aggregation state of polymer chains with hydrated ions or cosolvents. Scanning electron microscopy (SEM) images of ATMP-PVA hydrogel microstructures stained with different soaked cosolvents present different networks. The information on different chemical components will be stored in the ATMP-PVA gels. The flexible gel iontronic sensor with a hierarchical pyramid structure performed high linear sensitivity of 3224.2 kPa-1 and wide pressure response in the range of 0-100 kPa. The finite element analysis proved the pressure distribution at the gel interface of the gel iontronic sensor and the capacitation-stress response relation. Various cations, anions, amino acids, and saccharides can be discriminated, classified, and quantified with the gel iontronic sensor. The Hofmeister effect regulated chemical-mechanical interface performs the response and conversion of biological/chemical signals into electrical output in real time. The particular function to tactile with gustation percept will contribute promising applications in the human-machine interaction, humanoid robot, clinic treatment, or athletic training optimization.

The addition of crosslinked corn bran arabinoxylans with different gelling characteristics was associated with the pasting, rheological, structural, and digestion properties of corn starch

Crosslinked corn bran arabinoxylan (CLAX) is a food hydrocolloid that can be applied to improve the physicochemical and digestion properties of starch. However, the impact of CLAX with different gelling characteristics on starch properties remains elusive. Here, high cross-linked arabinoxylan (H-CLAX), moderate crosslinked arabinoxylan (M-CLAX), and low crosslinked arabinoxylan (L-CLAX) were fabricated to investigate their effects on the pasting, rheological, structural, and in vitro digestion property of corn starch (CS). The results showed that H-CLAX, M-CLAX, and L-CLAX differently increased the pasting viscosity and gel elasticity of CS, with H-CLAX exhibiting the greatest effect. The structural characterization of CS-CLAX mixtures showed that H-CLAX, M-CLAX, and L-CLAX differently enhanced the swelling power of CS and increased the hydrogen bonds between CS and CLAX. Furthermore, the addition of CLAX (especially H-CLAX) significantly reduced both the digestion rate and extent of CS, probably due to the increased viscosity and the formation of the amylose-polyphenol complex. This study provided new insights into the interaction between CS and CLAX, and could help to develop healthier foods with slow starch digestibility.

Targeted Micro-Phase separation – A generic design concept to control the elasticity of extrudable hydrogels

Hydrogels are ubiquitous in nature and technology. Controlling their mechanical properties and under-standing their complex microstructure is critical e.g. for 3D bioprinting or tissue engineering applications. Here a generic design concept for tuning the elasticity of extrudable gels at given polymer or particle concentration is presented. Targeted micro-phase separation leading to micro-heterogeneities (1–100 µm) yields high gel strength allowing for extrusion of uniform filaments with high shape accuracy as long as the heterogeneity length scale is small compared to the extruded filament diameter (>500 μm). Micro-mechanical and structural heterogeneity was enhanced in alginate hydrogels by accelerating crosslinking kinetics, corresponding to gel elasticity variation of more than two orders of magnitude (17 Pa to 2300 Pa), enabling filament extrusion (1046 µm) with high shape fidelity. Introducing poly(vinylalcohol) into gelatin gels resulted in more heterogeneous materials with a 2-fold increase in elasticity (951 Pa to 1993 Pa) and thinner filaments (908 µm to 590 µm). Higher ionic strength in Laponite-based hydrogels induced nanoparticle aggregation, leading to higher elasticity (857 Pa to 2316 Pa) enabling smooth filament extrusion. Eliminating the often tacitly assumed hydrogel uniformity on the microscale provides additional degrees of freedom to achieve high gel strength without increasing polymer, particle or crosslinker concentration.

Elasticity of Slide-Ring Gels.

Slide-ring gels are polymer networks with cross-links that can slide along the chains. In contrast to conventional unentangled networks with cross-links fixed along the chains, the slide-ring networks are strain-softening and distribute tension much more uniformly between their strands due to the so-called "pulley effect". The sliding of cross-links also reduces the elastic modulus in comparison with the modulus of conventional networks with the same number density of cross-links and elastic strands. We develop a single-chain model to account for the redistribution of monomers between network strands of a primary chain. This model takes into account both the pulley effect and fluctuations in the number of monomers per network strand. The pulley effect leads to modulus reduction and uniform tension redistribution between network strands, while fluctuations in the number of strand monomers dominate the strain-softening, the magnitude of which decreases upon network swelling and increases upon deswelling.

Negative and Positive Energetic Elasticity of Polydimethylsiloxane Gels.

We investigated the thermoelasticity of polydimethylsiloxane (PDMS) gels containing six types of solvents with different solubilities. The contribution of energetic elasticity to the total stress (σE/σ) ranges from +0.20 to -0.20 depending on the solvent species. The σE/σ values are positive for the solvents with low molecular mass. By contrast, it is negative for oligodimethylsiloxane (ODMS) or PDMS solvents acting as athermal solvents, each of which has the same chemical structure as the network strands. The investigation using a PDMS rubber without a solvent and the PDMS gels with various ODMS contents reveal a crossover of the σE/σ value from positive to negative with increasing ODMS content. The pronounced dependence of σE/σ on the solvent species and the negative energetic elasticity specific to the high contents of ODMS and PDMS unveil previously unknown aspects of thermoelasticity of polymer gels. The orientation coupling between the segments of the free polymeric chains and network strands is one of the possible scenarios to explain the negative energetic elasticity specific to the ODMS and PDMS solvents, because it stabilizes the aligned state, reducing the elastic energy.