Gel State Research Articles

Methods of changing low molecular weight gel properties through gelation kinetics.

Low molecular weight gels continue to attract notable interest, with many potential applications. However, there are still significant gaps in our understanding of these systems and the correlation between the pre-gel and final gel states. The kinetics of the gelation process plays a crucial role in the bulk properties of the hydrogel and presents an opportunity to fine-tune these systems to meet the requirements of the chosen application. Therefore, it is possible to use a single gelator for multiple applications. This review discusses four ways to modify the pre-gelled structures before triggering gelation. Such modifications can enhance the material's intended performance, which may result in significant advancements in high-tech areas, such as drug delivery, cell culturing, electronics, and tissue engineering.

Gel transition of active triblock copolymers

The self-propulsion of active matter leads to many non-equilibrium self-organization phenomena, and the conformational freedom of polymer chains can produce unique equilibrium self-assembly behaviors, which stimulates cross-disciplinary research between active matter and polymer physics. In this work, we use molecular dynamics simulations to investigate the modulation of self-propulsion activity on the gel transition of ABA triblock copolymers. The research results indicate that under different active forces and attractive strengths, the gel states formed by ABA copolymers can be divided into three types: stable polymer gels with stable percolation paths and uniform spatial distribution, dynamic polymer gels with constantly changing percolation path and strand conformation, and collapsed polymer gels aggregating into large percolating clusters. The spatial uniformity of active gels is related not only to the concentration fluctuation during the formation of the network, but also to the inconsistent movement of the network chains caused by the activity, which is manifested in the rotation of crosslinking points in the flexible system and the directional movement of the bundles along their contour directions in the semi-flexible and rigid systems. In terms of topological conformation of polymer networks, when the attractive strength between A blocks is strong, the proportion of loop increases with the active force increasing. When attractive strength is weak, inter- and intra-chain binding are unstable, and the conformation is easily changed by the activity drive, noise and other chain collisions, so the proportion of loop decreases with the active force increasing. The branching number of crosslinking points varies with active force, which is not only affected by the attraction strength, but also related to the rigidity of the network chain. Generally, the branch number of crosslinking points in semi-flexible networks is larger than that in flexible and rigid networks. In addition, the directional motion of active polymers induces anomalous diffusion in stable polymer gels. This study contributes to the understanding of the collective behavior of active polymers and serves as a guide for designing and implementing active polymeric materials.

Phase Inversion Gelation Process and Additive Effects on Hydrogel Film Properties of Cotton Cellulose.

During the preparation of cotton cellulose hydrogels using the phase inversion gelation method of N,N-dimethylacetamide/LiCl solution under ethanol vapor, acetone (AC), methyl ethyl ketone (MEK), or diethyl ketone (DEK) were added as additives, and their gelation state and the properties of the resulting hydrogels were evaluated. Adding the ketones to the cellulose solution caused an increase in the gelation time, but the solution viscosity decreased, indicating that the cellulose tended to aggregate in the solution. Among the hydrogels prepared by adding ketones, the water content was as high as 2050%, especially for AC and MEK. In these hydrogels, cellulose formed an agglomerated fibrous network of a few micron widths, forming a tuft-like entrapment space of about 10 to 100 μm size. The structure surrounded water and held it in the hydrogels. The FTIR results showed that the water, which formed hydrogen bonds, was retained within the hydrogel network. This structural configuration was determined to be conducive to maintaining the gel state against external deformation forces, especially in the case of the addition of MEK.

Anisotropic Polybenzimidazole Ion‐Solvating Membranes Composed of Aligned Nano‐Sheets for Efficient Acid‐Alkaline Amphoteric Water Electrolysis

AbstractAcid‐alkaline amphoteric water electrolysis (AAA‐WE) can produce green hydrogen under reduced voltage and energy consumption. However, its conflicting demands on ion exchange membranes to have both high ionic conductivity and barrier properties between H+ and OH− have thwarted its own development. Here, the preparation of anisotropic polybenzimidazole (PBI) ion‐solvating membrane (ISM) made of hundreds of 28 nm thick nano‐sheets (PBI‐aNS) from gel state PBI (PBI‐Gel) membranes via 2D‐polarized/1D shrinking process, in which loosely packed multi‐layer PBI nano‐fibrous assemblies are shrunken into hundreds of layers of tight 28 nm thick nano‐sheets, is reported. The resulting PBI‐aNS membranes possess excellent dual‐ion conductivity (H+ and OH−), good acid/alkali barrier capability, and robust mechanical properties. Acid‐alkaline amphoteric water electrolysis (AAA‐WE) using PBI‐aNS separators achieves a high current density of 1 A cm−2 at 1.4 V (with iR‐correction) under a voltage increasing rate of 6.1 mV h−1. This newly designed ISM will lead to new possibilities for the development of next‐generation water electrolysis devices with improved green hydrogen production efficiencies.

Color‐Tunable Room Temperature Afterglow of Non‐Conventional Organogels for Dynamic Anti‐Counterfeiting

AbstractLow‐molecular‐weight organogels with ultra‐long room temperature phosphorescent (RTP) are ideal materials for dynamic anti‐counterfeiting, due to their sensitive thermal‐responsive character. However, it is a great challenge to realize ultra‐long RTP in a single‐component organogel because conventional auxiliary groups for the promotion of gel formation are usually flexible, which increases non‐radiative decay through molecular motions to quench the RTP. Non‐conventional organogelators with rigid chemical structures may be able to alleviate the non‐radiative decay to maintain the phosphorescent characters in the gel state like in the crystalline state. In this work, potential low‐molecular weight phosphorescent organogelators with rigid chemical structures are predicted by using the descriptors derived from all‐atom molecular dynamics simulation, and successfully screen out two RTP non‐conventional organogelators. It is exciting that one of them exhibited ultra‐long RTP in the gel state. Furthermore, triplet‐to‐singlet Forster resonance energy transfer between the RTP gelator (donor) and fluorescent sulforhodamine 101 (SR101) (acceptor) in the gel state provided a long‐lived red fluorescence. Due to the sensitive thermal‐responsive property of organogel, the afterglow can be well switched between “on” and “off” with excellent fatigue‐resistant properties, which is promising for dynamic anti‐counterfeiting.

UV-Crosslinked Poly(N-isopropylacrylamide) Interpenetrated into Chitosan Structure with Enhancement of Mechanical Properties Implemented as Anti-Fouling Materials.

High-performance properties of interpenetration polymer network (IPN) hydrogels, based on physically crosslinked chitosan (CS) and chemically crosslinked poly(N-isopropylacrylamide) (PNiPAM), were successfully developed. The IPN of CS/PNiPAM is proposed to overcome the limited mechanical properties of the single CS network. In this study, the viscoelastic behaviors of prepared materials in both solution and gel states were extensively examined, considering the UV exposure time and crosslinker concentration as key factors. The effect of these factors on gel formation, hydrogel structures, thermal stabilities of networks, and HeLa cell adhesion were studied sequentially. The sol-gel transition was effectively demonstrated through the scaling law, which agrees well with Winter and Chambon's theory. By subjecting the CS hydrogel to the process operation in an ethanol solution, its properties can be significantly enhanced with increased crosslinker concentration, including the shear modulus, crosslinking degree, gel strength, and thermal stability in its swollen state. The IPN samples exhibit a smooth and dense surface with irregular pores, allowing for much water absorption. The HeLa cells were adhered to and killed using the CS surface cationic charges and then released through hydrolysis by utilizing the hydrophilic/hydrophobic switchable property or thermo-reversible gelation of the PNiPAM network. The results demonstrated that IPN is a highly attractive candidate for anti-fouling materials.

Peptide Gel Electrolytes for Stabilized Zn Metal Anodes.

The rechargeable aqueous Zn ion battery (AZIB) is considered a promising candidate for future energy storage applications due to its intrinsic safety features and low cost. However, Zn dendrites and side reactions (e.g., corrosion, hydrogen evolution reaction, and inactive side product (Zn hydroxide sulfate) formation) at the Zn metal anode have been serious obstacles to realizing a satisfactory AZIB performance. The application of gel electrolytes is a common strategy for suppressing these problems, but the normally used highly cross-linked polymer matrix (e.g., polyacrylamide (PAM)) brings additional difficulties for battery assembly and recycling. Herein, we have developed a gel electrolyte for Zn metal anode stabilization, where a peptide matrix, a highly biocompatible material, is used for gel construction. Various experiments and simulations elucidate the sulfate anion-assisted self-assembly gel formation and its effect in stabilizing Zn metal anodes. Unlike polymer gel electrolytes, the peptide gel electrolyte can reversibly transform between gel and liquid states, thus facilitating the gel-involved battery assembly and recycling. Furthermore, the peptide gel electrolyte provides fast Zn ion diffusion (comparable to conventional liquid electrolyte) while suppressing side reactions and dendrite growth, thus achieving highly stable Zn metal anodes as validated in various cell configurations. We believe that our concept of gel electrolyte design will inspire more future directions for Zn metal anode protection based on gel electrolyte design.

Rheological behavior of polysaccharide hydrogels of alginate reinforced by small amount of halloysite nanotubes for extrusion 3D printing

The rheological properties of hydrogels of a natural polysaccharide sodium alginate and small amount of clay nanotubes of halloysite were investigated. Changes of rheological properties during the transition from a semi-dilute polymer solution to a hydrogel upon cross-linking by calcium ions were shown. In the gel state, the samples have a yield stress, and their viscosity decreases with the shear rate, but the properties are quickly recovered after the load removal. It was obtained that the addition of up to 0.3 vol.% nanotubes of natural clay halloysite leads to an increase by several times of a storage modulus and an yield stress of the hydrogels. At the same time, the practically important properties of shear thinning and the rapid recovery of properties after the load removing make the nanocomposite hydrogels of alginate and halloysite nanotubes promising for use as ink for extrusion 3D printing.

Preparation of Preformed Submicron Crosslinked Polymer Coils for Conformance Control in Low-Permeability Reservoirs.

With the increasing development of low-permeability reservoirs, the significance of conformance control treatment has risen considerably. To address the conflict between injectability and plugging performance, as well as to enhance the deep migration capacity of conformance control agents, preformed submicron crosslinked polymer coils (SCPCs) have been manufactured using aqueous solution dispersion polymerization. Fourier transform infrared and scanning electron microscopy were employed to examine the chemical structure and micromorphology, while particle size distribution, zeta potential, rheological, and filtration properties were analyzed. The effectiveness of conformance control was confirmed through the parallel core displacement. The effective particle size of SCPCs was at a submicron level (500~800 nm). SCPCs exhibit a transitional threshold concentration between gel and sol states (0.25 wt%~0.5 wt%). SCPCs can efficiently block the 1.2 μm microporous filter membrane. The filtration time is up to 67.8 min. SCPCs can improve the water absorption rate of lower permeability cores from 21.21% to 57.89% with a permeability difference of 5. Therefore, SCPCs have good injectability, plugging performance, and deep migration capacity and can be used for conformance control in low-permeability reservoirs.

Polymer crystallization enabled excimer emission in anthracene-appended poly(ʟ-lactide)s

The design and development of solid-state excimer-emitters bear great potential for attaining efficient solid-state luminescent materials. In this study, we have synthesized anthracene-appended poly(ʟ-lactide)s (AAPs) to regulate the arrangement of anthracene moieties by controlling the crystallization and polymorphic form of covalently linked poly(ʟ-lactide) (PLLA). In the high molecular weight AAP, the fluorescence intensity mainly arises from the monomeric anthracene moieties, whereas in the low molecular weight AAP, the excimer emission was observed depending on the structure and morphology of covalently-linked PLLA. The monomeric emission is predominantly observed in amorphous polymer due to the molecular level dispersion of covalently-linked anthracene moieties throughout the polymer matrix. When the polymer was crystallized under different conditions, covalently-linked anthracene moieties were excluded from polymer crystals or crystalline lamellae and are located on the surface or at the interface, which is advantageous for regulating the geometry of anthracene moieties. In the case of single crystals of PLLA, covalently-linked anthracene moieties assemble on the surface and emit mainly in their monomeric state due to the lack of π-stacking. In the melt-crystallized sample (α form), covalently-linked anthracene moieties reside at the interface of crystalline and amorphous domains by either dipolar interactions or π-stacking and fluorescence arising from anthracene excimers and monomers. In the gel state (ε form), only the excimer emission was observed due to the effective interactions between the anthracene moieties in the presence of excess solvent in the amorphous domains. In this way, polymer crystallization played a significant role in determining the arrangement of covalently-linked anthracene moieties in AAP. This study reveals the role of polymer crystallization on the excimer evolution in fluorophore-appended semicrystalline polymers and provides new insight into the design and development of fluorophore-appended polymers for optoelectronic devices.

Injectable Thermoresponsive Microparticle/Hydrogel System with Superparamagnetic Nanoparticles for Drug Release and Magnetic Hyperthermia Applications.

Cancer is a disease that continues to greatly impact our society. Developing new and more personalized treatment options is crucial to decreasing the cancer burden. In this study, we combined magnetic polysaccharide microparticles with a Pluronic thermoresponsive hydrogel to develop a multifunctional, injectable drug delivery system (DDS) for magnetic hyperthermia applications. Gellan gum and alginate microparticles were loaded with superparamagnetic iron oxide nanoparticles (SPIONs) with and without coating. The magnetic microparticles' registered temperature increases up to 4 °C upon the application of an alternating magnetic field. These magnetic microparticles were mixed with drug-loaded microparticles, and, subsequently, this mixture was embedded within a Pluronic thermoresponsive hydrogel that is capable of being in the gel state at 37 °C. The proposed DDS was capable of slowly releasing methylene blue, used as a model drug, for up to 9 days. The developed hydrogel/microparticle system had a smaller rate of drug release compared with microparticles alone. This system proved to be a potential thermoresponsive DDS suitable for magnetic hyperthermia applications, thus enabling a synergistic treatment for cancer.

Regulation of fluorescence, morphology, surface wettability and function of naphthalimide-based self-assembly system by metal coordination

Three naphthalimide-based supramolecular gelators (N1, N2 and N3) that contained one, two, or three naphthalimide groups, respectively, were designed and synthesized, and the self-assembly processes of the three gelators were studied using different technique. Their self-assembly behavior could be regulated through the number of terminal branches. More importantly, their self-assembled structure, fluorescence behavior and surface wettability and function could be regulated through metal coordination, and helical nanofibers could be formed by gel N2 with Cd2+, Co2+, Eu3+, Tb3+, Mn2+, Ni2+ and Hg2+. The fluorescence emission intensities of these gels could change with different degrees under the addition of different metal ions, and a super-hydrophilic surface could be obtained from xerogel N3 in the presence of Co2+, Eu3+, Mn2+ and Tb3+. Specifically, gelator N3 could selectively and sensitively respond to Fe2+ in the solution and gel state with a response time of 0.5 s and a low limit of detection of 1.84 nM. This work provided a new regulation method for the supramolecular self-assembly process.

The impact of palmitoyl glycyl-histidyl-lysine on phospholipid model membranes

BackgroundPalmitoyl glycyl-histidyl-lysine (Pal-GHK), a peptide amphiphile derived from the GHK tripeptide, has gained attention for its diverse bioactive properties and applications in skincare formulations. This study delves into the interactions and effects of Pal-GHK on phospholipid model membranes. Using a thin film hydration-sonication method, Pal-GHK and hydrogenated soy phosphatidylcholine (HSPC) were combined to create lipid vesicles. MethodsVarious analytical techniques, including dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), fluorescence polarization (FP), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), were employed to comprehensively assess the impact of Pal-GHK on the lipid bilayer domain. Significant FindingsThe results reveal insights into the size, zeta potential, storage stability, morphology, thermotropic phase behavior, molecular arrangement, and lipid ordering within the HSPC membranes in the presence of Pal-GHK. The introduction of Pal-GHK increased vesicle size, surface charge density, and storage stability in HSPC-rich vesicles. The addition of Pal-GHK dominated the endothermic phase behavior of the lipid vesicles and increased the proportion of gauche conformation in the acyl chains of HSPC, inducing molecular fluidity in the hydrophobic region of the lipid membrane in its gel state. These findings contribute to our understanding of the interactions between Pal-GHK and lipid model membranes, holding significance for various scientific disciplines and potential applications.

The role of the solvent nature in stretching polymer solutions (polyacrylonitrile spinning using different solvents)

We investigated how different solvents' affinity with polyacrylonitrile affects the formation of a jet that leads to stable fiber spinning. The study focused on two concentrations, one near and one above the crossover point where the topological entanglements are formed in the semi-dilute solutions. The role of the physical parameters of the solutions, including solvent-polymer affinity, viscosity, surface tension, and relaxation times, was analyzed. The experiment involved the uniaxial deformation of a solution drop under its weight, observed using a high-speed microscopic camera. The stability of the jet was associated with the relaxation time and solvent-polymer affinity. The continuous fiber spinning is mainly determined by the high enough polymer concentration in the solution, and the solvent nature, or by how the solution state is close to the theta conditions. Bicomponent mixed solvents offer two viable routes to achieve this – evaporating a more volatile component from the mixture to increase the polymer concentration, or modifying the solvent with a combination of solvents of different solvent quality. Both approaches have been experimentally validated, enabling the production of continuous stable fibers in the gel stretching regime. In this case, the jet stretching occurs under conditions Wi > 1. Thereby, the transition to the gel state promotes the necessary conditions for macromolecule orientation during fiber spinning.

Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose.

The dynamics of water and agarose molecules in an agarose aqueous solution has been studied by means of quasielastic neutron scattering (QENS). The dynamic structure factor S (Q,E) of the agarose aqueous solution was fitted well to the sum of the Lorentz and delta function. The former is attributed to the diffusive motion of water molecules and the latter to the local vibrational motion of agarose molecules. The self-diffusion coefficient D of water molecules was obtained from the Q-dependence of the width of the Lorentz function, while the mean square displacement <u2> of agarose molecules was obtained from the Q-dependence of the intensity of the delta term. In the cooling direction, both D and <u2> decreased with decreasing temperature and showed discontinuous changes around the thermal gelation temperature (around 314 K). In the heating direction, however, D and <u2> did not show the obvious change below 343 K, indicating a large hysteresis effect. The present results of <u2> and D revealed that the thermal gelation suppresses the motion of the polymer and accelerates the diffusion of water molecules. The activation energy Ea of the diffusion of water in the sol state is the same as that of bulk water, but the Ea in the gel state is clearly smaller than that of bulk water.

Fibrous whey protein mediated homogeneous and soft-textured emulsion gels for elderly: Enhancement of bioaccessibility for curcumin

Homogeneous and soft-textured food gels are critical for designing precise and personalized nutrient food for elderly. Effects of whey protein morphology (fibrous and granular) with/without NaCl addition on oil-water state and texture properties of protein emulsion gels were investigated, to explore the feasibility of developing homogeneous and soft-textured food for elderly. Lower gelation temperature and higher stability of its emulsion droplets, resulted in fibrous whey protein emulsion gels (FWPG) had even distribution of embedded oil droplets, compared to native whey protein emulsion gels. FWPG had the lowest hardness and chewiness, and exhibited better tolerance to the harden effects of NaCl on emulsion gels. FWPG can deliver curcumin more effectively during simulated gastrointestinal digestion, as evidenced by higher retention ratio and enhancement of bioaccessibility (increased by ∼ 20 %). This study provided new strategy to fabricate a homogenous emulsion gel using fibrous whey protein and to design multi-nutrient food gels for elderly.

Exploring Potential of Gellan Gum for Enhanced Oil Recovery.

Extensive laboratory and field tests have shown that the gelation response of gellan gum to saline water makes it a promising candidate for enhanced oil recovery (EOR). The objective of this mini-review is to evaluate the applicability of gellan gum in EOR and compare its efficiency to other precursors, in particular, hydrolyzed polyacrylamide (HPAM). At first, the "sol-gel" phase transitions of gellan gum in aqueous-salt solutions containing mono- and divalent cations are considered. Then the rheological and mechanical properties of gellan in diluted aqueous solutions and gel state are outlined. The main attention is paid to laboratory core flooding and field pilot tests. The plugging behavior of gellan in laboratory conditions due to "sol-gel" phase transition is discussed in the context of conformance control and water shut-off. Due to its higher strength, gellan gum gel provided ~6 times greater resistance to the flow of brine in a 1 mm-width fracture compared to HPAM gel. The field trials carried out in the injection and production wells of the Kumkol oilfield, situated in Kazakhstan, demonstrated that over 6 and 11 months, there was an incremental oil recovery of 3790 and 5890 tons, respectively. To put it into perspective, using 1 kg of dry gellan resulted in the incremental production of 3.52 m3 (or 22 bbls) of oil. The treatment of the production well with 1 wt.% gellan solution resulted in a considerable decrease in the water cut up to 10-20% without affecting the oil flow rate. The advantages and disadvantages of gellan compared to HPAM are analyzed together with the economic feasibility of gellan over HPAM. The potential for establishing gellan production in Kazakhstan is emphasized. It is anticipated that gellan gum, manufactured through fermentation using glucose-fructose syrup from Zharkent and Burunday corn starch plants, could be expanded in the future for applications in both the food industry and oil recovery.

Branched Copolymer Surfactants as Versatile Templates for Responsive Emulsifiers with Bespoke Temperature‐Triggered Emulsion‐Breaking or Gelation

AbstractIt has been found that the thermoresponsive behavior of emulsions stabilized by block copolymer surfactants (BCSs) can induce either gelation or emulsion break‐up with mild temperature changes. A hydrophilic, steric‐stabilizing component of the BCS, polyethylene glycol methacrylate (PEGMA), is crucial to control the thermoresponsive behavior of the emulsions: longer PEG chains (950 g mol−1) lead to thermoregulation, whereas shorter PEGM chains (500 or 300 g mol−1) lead to emulsion break‐up upon mild heating. Additionally, the relative abundance of PEGMA to the thermoresponsive component in the BCS controls the gelation temperature of BCS‐stabilized emulsions. Small‐angle neutron scattering and transmission electron microscopy reveal that the BCS forms oblate ellipsoids which grow anisotropically with temperature. In samples that form a gel, there is evidence that these nano‐objects form supra‐colloidal structures, which are responsible for the gel mesophase formation. An optimal BCS can form emulsions that transition from a liquid to gel state when warmed above 32 °C. This makes the system ideal for in situ gelation upon contact with the body. Overall, this study highlights the great potential of BCSs in generating thermoresponsive emulsions for drug delivery and other healthcare applications.

Metal Ion-Induced Formation of Metallogels by Visible-Light-Responsive Phenylalanine-Functionalized Arylazopyrazole Ligands

A visible-light-responsive arylazopyrazole-functionalized phenylalanine (4-MeS-AAP-NF) derived ligand was designed and synthesized, and it was found to form metallogels with reversible photo-responsive properties in mixed methanol/water (MeOH/H2O) solvents. The gelation behavior of the 4-MeS-AAP-NF ligand in the presence of different divalent metal ions in mixed methanol/water (MeOH/H2O) solvents at pH~11.60 was studied. It was found that the 4-MeS-AAP-NF ligand alone could not self-assemble to form any gels. However, in the presence of divalent metal ions, it readily formed the assembled metallogels in an alkaline aqueous/methanol solution with various morphologies. The results suggest that the gelation process was triggered by divalent metal ions. The presence of the AAP moiety in the gel matrix rendered the metallogel assemblies photo-responsive, and the reversible gel-to-sol phase transition was studied by UV-vis spectroscopy. The gels showed a slow, reversible visible-light-induced gel-to-sol phase transition under blue (λ = 405 nm) and then sol-to-gel transition by green light (λ = 530 nm) irradiation, resulting in the re-formation of the original gel state. The morphology and viscoelastic properties of the yellow–orange opaque metallogels were characterized by scanning electron microscopy (SEM) and rheological measurement, respectively.

Preparation of Polyurethane–Urea Fibers with Controlled Surface Morphology via Gel State

It is widely known that skin irritation can be induced by interactions between polymer fibers constituting clothing and the skin, leading to skin inflammation and unfavorable dermatological reactions. Thus, significant endeavors have been directed toward ameliorating this phenomenon. This study engineered synthetic fibers with reduced potential for skin irritation. This was achieved via a strategy inspired by the inherent smoothness of silk fibers, which exhibit minimal friction and irritation against the skin. This investigation focused on urethane fibers, a class of synthetic fibers frequently used in textile applications. Hydrogel cross-linked polyurethane–urea fibers were subjected to controlled swelling in different hydrophilic mixed-solvent environments. Subsequent freeze-drying procedures were employed to yield fibers with diverse surface morphologies and encompassing features such as elevations and creases. The correlation between the compositions of the solvent mixtures used and the resulting surface morphologies of the fibers was rigorously assessed through polarized light and scanning electron microscopies. Additionally, the interplay between the degree of swelling and the tensile strength of the fabricated fibers was comprehensively analyzed. Consequently, the methodological combination of swelling and freeze-drying endowed the polyurethane–urea fibers with various surface profiles. Future studies will delve into the intricate connection between fiber surface characteristics and their potential to induce skin irritation. It is envisaged that such investigations will substantially contribute to the refinement of textile fibers designed for enhanced compatibility with the skin.