Synergy of a complementary ionic biogel network for neurohaptics

Abstract

Embodiments relate to ionic biogels designed to exhibit thermoreversibility and / or electrical conductivity. In particular, ionic biogels may simultaneously exhibit both thermoreversibility and electrical conductivity. Embodiments further relate to methods of making and using the ionic biogels. Methods may include combining conductive polymers, one or more ionic liquids, and one or more salts to form a first solution, and adding matrix-forming polymers and one or more plasticizers to the first solution to form the ionic biogel.

Description

Atty. Ref. No. 0073605-001078SYNERGY OF A COMPLEMENTARY IONIC BIOGEL NETWORK FOR NEUROHAPTICSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This patent application is related to and claims the benefit of priority of U. S. Provisional Application 63 / 721,776, filed on November 18, 2024. The entire contents of this application are incorporated by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH DEVELOPMENT

[0002] This invention was made with government support under Grant Nos. ECCS2309323, DGE2243979, 2319139 and 2419142 awarded by the National Science Foundation and under Grant Nos. EB030140 and NS115667 awarded by the National Institutes of Health. The Government has certain rights in the invention.FIELD

[0003] Embodiments relate to ionic biogels designed to exhibit thermoreversibility and / or electrical conductivity. In particular, ionic biogels may simultaneously exhibit both thermoreversibility and electrical conductivity. Embodiments further relate to methods of making and using the ionic biogels.BACKGROUND

[0004] Hydrogels that are electrically conducting or semiconducting have emerged as promising bioelectronic platforms due to their tissuedike softness combined with efficient electron or hole transport capabilities. These materials are increasingly explored for applications such as neural interfaces, biosensors, and soft electronic devices, where mechanical compliance and electrical functionality are both critical. Conversely, thermoreversible hydrogels are characterized by their ability to undergo reversible gel-sol transitions in response to temperature changes, oftenAtty. Ref. No. 0073605-001078facilitated by dynamic non-covalent interactions such as hydrogen bonding or hydrophobic effects. These properties enable mechanical adaptability and repeatable shape-shifting, making thermoreversible hydrogels suitable for various biomedical and soft robotic applications.

[0005] Integrating electrical conductivity or semi conductivity with thermoreversibility within a single hydrogel system presents a significant challenge, as these functionalities are often antagonistic in nature. Conductive networks typically require stable, percolated structures, such as ^-conjugated polymer networks, that resist rearrangement under thermal cycling, whereas thermoreversible behavior depends on reversible, non-covalent interactions that facilitate phase transitions. Achieving a balance between these properties necessitates precise control over the hydrogel’s phase morphology and the interactions between its constituent polymers. Recent research efforts have focused on manipulating phase separation processes, such as solvent-driven phase separation and thermodynamic tuning, to create bicontinuous morphologies that support both ionic and electronic conduction. However, these permanent morphologies often lack the dynamic reconfigurability required for thermoreversibility, limiting their utility in stimuli-responsive applications.SUMMARY

[0006] Current approaches to developing conductive hydrogels with thermoreversible properties include combining physically crosslinked matrices with intrinsically conducting polymers. While strategies to enhance electrical conductivity often involve increasing polymer solubility or hydrophilicity, these modifications can compromise thermoreversible behavior. Conversely, controlling phase separation near the spinodal line offers a pathway to create transient, percolated networks that are both conductive and thermally reversible. Understanding theAtty. Ref. No. 0073605-001078thermodynamic and kinetic parameters governing phase separation, such as polymer-polymer interactions, phase mobility, and mixing sequences, is essential for designing such systems.

[0007] Embodiments described herein relate to hydrogel systems engineered to simultaneously exhibit thermoreversible and conductive properties, addressing a longstanding challenge in stimuli-responsive bioelectronic materials. Specifically, embodiments focus on controlling phase morphology within ionic biogels to balance the competing requirements of network reorganization for thermoreversibility and network percolation for electrical conductivity. By leveraging principles of phase thermodynamics and precise manipulation of polymer concentration and mixing sequences, these materials can transition between different morphological states, enabling both rapid gel-sol transitions and high levels of electrical performance.

[0008] In particular, the systems described herein may utilize a combination of ionically conductive, nucleated morphologies and bicontinuous phases near the spinodal threshold, allowing the materials to achieve a unique balance between viscoelastic flow and electronic conduction. These innovations result in biogels with low storage modulus, high conductivity, and thermoreversible behavior, making them suitable for long-term, reusable neural interfaces and other bioelectronic applications. The materials can be tailored to function effectively across various conditions, maintaining low skin-contact impedance over extended periods and across diverse hair types, thereby supporting stable neural signal detection and mechanical-electrical stimulation.

[0009] In an exemplary embodiments, a method of making a nucleated ionic biogel includes combining conductive or semiconductive polymers, one or more ionic liquids, and one or moreAtty. Ref. No. 0073605-001078salts to form a first solution; and adding matrix-forming polymers and one or more plasticizers to the first solution to form the nucleated ionic biogel.

[0010] In some embodiments, a concentration of the conductive or semiconductive polymers is greater than 0 w / w% and less than or equal to 200 w / w% relative to a concentration of the matrix-forming polymers.

[0011] In some embodiments, a concentration of the conductive or semiconductive polymers is greater than or equal to 100 w / w% and less than or equal to 125 w / w% relative to a concentration of the matrix-forming polymers.

[0012] In some embodiments, the conductive or semiconductive polymers are selected from the group consisting of poly(3,4-ethylenedi oxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly[3,3 '-bis[2-[2-(2 -methoxyethoxy )ethoxy]ethoxy]-2,2':5',2''-terthiophene-5, 5"-diyl] (pg2T-T).

[0013] In some embodiments, the conductive or semiconductive polymers are PEDOT: PSS.

[0014] In some embodiments, the ionic liquids are selected from the group consisting of 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), l-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf), and deep eutectic solvents (DES).

[0015] In some embodiments, the salts are selected from the group consisting of sodium chloride, potassium chloride, and lithium chloride.

[0016] In some embodiments, the matrix-forming polymers are selected from the group consisting of gelatin, agar, and cellulose.

[0017] In some embodiments, the plasticizers are selected from the group consisting of glycerol and dimethyl sulfoxide.Atty. Ref. No. 0073605-001078

[0018] In an exemplary embodiment, a nucleated ionic biogel is formed from the method described above.

[0019] In an exemplary embodiment, a method of making a nucleated ionic biogel includes combining poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOTPSS), one or more ionic liquids, and one or more salts to form a first solution; and adding gelatin and glycerol to the first solution to form the nucleated ionic biogel.

[0020] In some embodiments, a concentration of the PEDOT: PSS is greater than or equal to 100 w / w% and less than or equal to 125 w / w% relative to a concentration of the matrix-forming polymers.

[0021] In an exemplary embodiment, a method of making a bicontinuous ionic biogel includes combining matrix-forming polymers and one or more plasticizers to form a first solution; and adding one or more salts and one or more ionic liquids to the first solution to form a second solution; and adding conductive or semiconductive polymers to the second solution to form the bicontinuous ionic biogel.

[0022] In some embodiments, a concentration of the conductive or semiconductive polymers is greater than 0 w / w% and less than or equal to 200 w / w% relative to a concentration of the matrix-forming polymers.

[0023] In some embodiments, the conductive or semiconductive polymers are selected from the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedi oxy thiophene) polystyrene sulfonate (PEDOT: PSS), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly [3,3 '-bis[2-[2-(2 -methoxy ethoxy )ethoxy]ethoxy]-2,2':5',2"-terthiophene-5, 5"-diyl] (pg2T-T).

[0024] In some embodiments, the conductive or semiconductive polymers are PEDOT: PSS.Atty. Ref. No. 0073605-001078

[0025] In some embodiments, the ionic liquids are selected from the group consisting of 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), l-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf), and deep eutectic solvents (DES).

[0026] In some embodiments, the salts are selected from the group consisting of sodium chloride, potassium chloride, and lithium chloride.

[0027] In some embodiments, the matrix-forming polymers are selected from the group consisting of gelatin, agar, and cellulose.

[0028] In some embodiments, the plasticizers are selected from the group consisting of glycerol and dimethyl sulfoxide.

[0029] In an exemplary embodiment, a bicontinuous ionic biogel formed from the method described above.

[0030] Other details, objects, and advantages of our compositions, methods, and systems will become apparent as the following description of certain exemplary embodiments thereof proceeds.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other objects, aspects, features, advantages, and possible applications of embodiments of the present innovation will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings. Like reference numbers used in the drawings may identify like components.

[0032] FIG. 1 is a schematic illustration of a thermodynamics-driven material design of ionic biogel based on the mixing strategy - nucleated, bicontinuous (with polymer concentration less than St), bicontinuous (with polymer concentration more than Si), and layered (bicontinuous system without mixing). The nucleated system forms isolated polymer domains independent ofAtty. Ref. No. 0073605-001078the gel-based matrix, forming a stable thermodynamic system where increasing polymer concentration only results in an increased number of isolated polymer domains with no charge pathway. The bicontinuous system forms an enthalpy-dominated system, where the increased polymer concentration (more than S() changes the phase morphology from a binodal system to a spinodal decomposition with percolated polymer networks to facilitate a charge pathway.

[0033] FIG. 2A is a flowchart of an exemplary method of forming a bicontinuous system.

[0034] FIG. 2B is a flowchart of an exemplary method of forming a nucleated system.

[0035] FIG. 3 includes optical images showing the initial phase composition and mobility of the gelatin matrix that change the phase morphology of the ionic biogel. This can be simulated using the Cahn-Hilliard equation, validating the optical images of different material composition systems.

[0036] FIG. 4 is a schematic illustration of the synergistic effect of the biogel phase (gelatinglycerol-salt) and ionic phase (PEDOT: PSS-Ionic Liquid).

[0037] FIG. 5 includes schematic illustrations of the effect of increasing the PEDOT: PSS concentration in the nucleated system (increase in PEDOT: PSS phase size) and the bicontinuous system (onset of percolation of the PEDOT: PSS network).

[0038] FIG. 6 is a schematic illustration comparing the efficiency of thermoreversibility of nucleated, bicontinuous < St, and bicontinuous > St.

[0039] FIG. 7 is a graph showing loss tangent as a function of temperature for nucleated 35 w / w%.

[0040] FIG. 8 is a graph showing comparison of loss tangent as a function of temperature for bicontinuous <and nucleated 100 w / w% systemsAtty. Ref. No. 0073605-001078

[0041] FIG. 9 is a graph showing comparison of loss tangent as a function of temperature for bicontinuous > SLand nucleated 100 w / w% systems.

[0042] FIG. 10 is a graph showing comparison of loss tangent as a function of temperature for bicontinuous = 100 w / w% and nucleated 100 w / w% systems.

[0043] FIG. 11 is a bar graph showing a comparison of rheological parameters, such as changes in loss tangent and viscosity, for different concentrations of the bicontinuous system.

[0044] FIG. 12 is a bar graph showing a comparison of rheological parameters such as changes in loss tangent, viscosity, and time constant of the isothermal cycle for different ionic liquids used for nucleated 35 w / w%.

[0045] FIG. 13 shows graphs demonstrating time constant of isothermal relaxation of (top) storage modulus and (bottom) loss modulus over 20 thermal cycles for bicontinuous, nucleated, and non-ionic biogels.

[0046] FIG. 14 shows graphs demonstrating a Comparison of the time constant of isothermal relaxation of (top) storage modulus and (bottom) loss modulus over 20 thermal cycles for bicontinuous 35 w / w%, 50 w / w%, and 100 w / w%.

[0047] FIG. 15 is a schematic illustration of phase dynamics and the onset of turbidity for nucleated and bicontinuous systems < Stusing UV-Vis - temperature. Irreversible phase dynamics of bicontinuous systems > St.

[0048] FIG. 16 shows graphs demonstrating variation of UV-Vis absorbance as a function of temperature during (top) heating and (bottom) cooling of the nucleated 35 w / w% system.

[0049] FIG. 17 is a graph showing a summary of the UV-Vis absorbance at 800 nm wavelength to show the onset of turbidity of the nucleated 35 w / w% system.Atty. Ref. No. 0073605-001078

[0050] FIG. 18 is a graph showing a summary of the UV-Vis absorbance at 800 nm wavelength to show the onset of turbidity of the bicontinuous 50 w / w% system.

[0051] FIG. 19 is a graph showing failure of turbidity and huge thermal hysteresis of the bicontinuous 100 w / w%.

[0052] FIG. 20 is a bar graph showing correlation of change in UV-Vis absorbance and rheological parameters such as loss tangent and viscosity.

[0053] FIG. 21 is a schematic showing the phases of nucleated and bicontinuous systems that influence the interfacial enthalpy of the phases as reflected in differential scanning calorimetry (DSC).

[0054] FIG. 22 is a graph showing DSC curves of nucleated 100 w / w% systems, demonstrating the onset of interfacial enthalpy.

[0055] FIG. 23 is a graph showing DSC curves of bicontinuous 100 w / w% systems, demonstrating the onset of interfacial enthalpy.

[0056] FIG. 24 includes optical images to show the hole pathway through the percolated polymeric PEDOT phase in four different types of material systems.

[0057] FIG. 25 schematic of the organic electrochemical transistor (OECT) and the transfer characteristics for two different channel material systems: nucleated and bicontinuous < S, to result in a leaky OECT, and bicontinuous > Stto yield a standard OECT.

[0058] FIG. 26 is a bar graph showing a conductivity comparison of different types of ionic biogels - layered (100 w / w%), bicontinuous (50, 100, 200 w / w%), and nucleated (100 w / w%).

[0059] FIG. 27 is a graph showing electrochemical impedance spectra (EIS) of bicontinuous (50, 100, 200 w / w%) and nucleated (100 w / w%) systems.Atty. Ref. No. 0073605-001078

[0060] FIG. 28 is a graph showing transfer characteristics of OECT with channel materials of nucleated (200 w / w %).

[0061] FIG. 29 is a graph showing transfer characteristics of OECT with channel materials of bicontinuous (100 w / w %).

[0062] FIG. 30 is a bar graph showing a comparison of the peak transconductance and on-current of OECT with channel materials: bicontinuous (75 w / w%, 100 w / w%, 200 w / w%, and 300 w / w%) and nucleated (200 w / w%).

[0063] FIG. 31 is a bar graph showing a comparison of figure of merit and on-off ratio of bicontinuous (75 w / w%, 100 w / w%, 200 w / w%, and 300 w / w%).

[0064] FIG. 32 is a bar graph showing a comparison of hole mobility of bicontinuous (75 w / w%, 100 w / w%, 200 w / w%, and 300 w / w%).

[0065] FIG. 33 is a graph showing variation of peak transconductance of bicontinuous (100 w / w % and 300 w / w %).

[0066] FIG. 34 is a graph showing variation of on-current of bicontinuous (100 w / w % and 300 w / w %).

[0067] FIG. 35 is a bar graph showing a comparison of Seebeck coefficient between bicontinuous (75 w / w%, 100 w / w%, 200 w / w%, and 300 w / w%) and nucleated (200 w / w%) systems.

[0068] FIG. 36 includes a schematic illustration of the experimental setup to analyze neural response during mechanical and electrical stimulations, and a schematic illustration of the wearable electrical stimulator array placed on the arm.Atty. Ref. No. 0073605-001078

[0069] FIG. 37 is a graph showing the skin-contact impedance of bicontinuous (100 w / w %), nucleated (100 w / w%), commercial, and non-ionic biogels across different human subjects (averaged over days).

[0070] FIG. 38 is a graph showing the skin-contact impedance of bicontinuous (100 w / w %), nucleated (100 w / w%), commercial, and non-ionic biogels across different days (averaged over subjects).

[0071] FIG. 39 is a graph showing power amplitude showing increased power in the alpha band during the eye-closing state for bicontinuous systems.

[0072] FIG. 40 is a graph showing power amplitude showing increased power in the alpha band during the eye-closing state for nucleated systems.

[0073] FIG. 41 is a graph showing amplitude of event-related desynchronization (ERD) during sensory mechanical vibration using bicontinuous electrodes over 3 days.

[0074] FIG. 42 is a power spectrogram of EEG during electrical stimulation at 150 Hz.

[0075] FIG. 43 is a power spectrum of EEG during haptic sensation applied at different frequencies (5 Hz - 500 Hz) on day 1.

[0076] FIG. 44 is a power spectrum of EEG during haptic sensation applied at different frequencies (5 Hz - 500 Hz) on day 7.

[0077] FIG. 45 is a table showing various properties of phase morphologies.

[0078] FIG. 46 shows an AFM analysis of nucleated 35 w / w% to confirm the hierarchical porous nature of the material.

[0079] FIG. 47 shows an AFM analysis of bicontinuous 100 w / w% to confirm the hierarchical porous nature of the material.

[0080] FIG. 48 shows micro-computed tomography of nucleated 100 w / w%.Atty. Ref. No. 0073605-001078

[0081] FIG. 49 shows micro-computed tomography of bicontinuous 100 w / w%.

[0082] FIG. 50 is a graph showing UV-Vis spectrum of bicontinuous 150 w / w% and nucleated 35 w / w%.

[0083] FIG. 51 shows a WAXS analysis of nucleated 35 w / w% across different temperatures.

[0084] FIG. 52 shows a WAXS analysis of nucleated 35 w / w% across different temperatures.

[0085] FIG. 53 shows a WAXS analysis of bicontinuous 100 w / w% across different temperatures.

[0086] FIG. 54 is an image showing the results of a skin irritation test on a human subject after 7 days of constant contact with the ionic biogel during on the neurohaptics experiments.

[0087] FIG. 55 shows results of a cell viability assessment of the ionic biogel against a control for 24 hours and 48 hours.

[0088] FIG. 56 shows results of a cell viability assessment of the ionic biogel against a control for 24 hours and 48 hours.

[0089] FIG 57 is a graph showing the difference in particle size distribution between bicontinuous 100w / w% and nucleated 100w / w%.DETAILED DESCRIPTION

[0090] The following description is of exemplary embodiments and methods of use that are presently contemplated for carrying out the present invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles and features of various aspects of the present invention. The scope of the present invention is not limited by this description.Atty. Ref. No. 0073605-001078

[0091] Embodiments relate to ionic biogels designed to exhibit one, or preferably both, of thermoreversibility and electrical conductivity. These ionic biogels include two main components: an ionic phase and a gel phase.

[0092] The ionic phase includes one or more conductive or semiconductive polymers. In some embodiments, the conductive or semiconductive polymers may include poly(3,4-ethylenedi oxythiophene) (PEDOT), poly(3,4-ethylenedi oxythiophene) polystyrene sulfonate (PEDOT: PSS), poly(3-hexylthiophene-2,5-diyl) (P3HT), Poly[3,3'-bis[2-[2-(2-methoxyethoxy)ethoxy]ethoxy]-2,2':5',2"-terthiophene-5,5"-diyl] (pg2T-T), and / or the like.

[0093] The ionic phase may further include one or more ionic liquids. Examples of such ionic liquids include 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf), Deep Eutectic Solvents (DES), and / or the like.

[0094] The gel phase provides structural support and forms the matrix of the biogel. This phase typically includes one or more polymers (e.g., matrix-forming polymers), such as gelatin, agar, and cellulose, which offers biocompatibility and mechanical stability.

[0095] The gel phase may further include one or more plasticizers. In some embodiments, the plasticizers may include glycerol and / or dimethyl sulfoxide (DMSO).

[0096] The gel phase may further include one or more salts. In some embodiments, the salts may include sodium chloride (NaCl), potassium chloride (KC1), and / or lithium chloride (LiCl).

[0097] In preferred embodiments, some or all components of the ionic and gel phases are biocompatible, ensuring safety and suitability for biomedical applications.

[0098] Embodiments also relate to methods for making the described ionic biogels. As illustrated in FIG. 1, the specific method of fabrication significantly influences the resultingAtty. Ref. No. 0073605-001078biogel morphology. The morphology refers to the internal structure or arrangement of the ionic and gel phases within the biogel, which in turn affects its properties. A more detailed discussion of these effects will follow.

[0099] In one embodiment, the biogel is engineered to have a nucleated morphology. This structure features isolated conductive or semiconductive polymer domains, such as droplets or clusters, scattered within the gel matrix. These domains are formed when the ionic phase nucleates separately from the surrounding gel phase, resulting in a non-percolating, dispersed distribution of conductive regions. Examples of a nucleated morphology are depicted in FIGS. 3 and 5.

[0100] In a nucleated morphology, a concentration of the conductive or semiconductive polymers relative to a concentration of the matrix-forming polymers may be between 0 and 200 w / w%. In some embodiments, the concentration may be greater than 0 w / w%, at least 1 w / w%, at least 5 w / w%, at least 10 w / w%, at least 25 w / w%, at least 50 w / w%, at least 100 w / w%, at least 150 w / w%, at least 175 w / w%, at least 190 w / w%, at least 195 w / w%, and / or the like. In other embodiments, the concentration may be no greater than 200 w / w%, no greater than 195 w / w%, no greater than 190 w / w%, no greater than 175 w / w%, no greater than 150 w / w%, no greater than 100 w / w%, no greater than 50 w / w%, no greater than 25 w / w%, no greater than 10 w / w%, no greater than 5 w / w%, and / or the like.

[0101] Conversely, in another embodiment, the biogel adopts a bicontinuous morphology. Here, the conductive or semiconductive polymer and the gel matrix form interconnected pathways throughout the structure, enabling electrons and holes to flow freely across the entire gel. This morphology is also illustrated in FIGS. 3 and 5.Atty. Ref. No. 0073605-001078

[0102] In a bicontinuous morphology, a concentration of the conductive or semiconductive polymers relative to a concentration of the matrix-forming polymers may be between 0 and 300 w / w%. In some embodiments, the concentration may be greater than 0 w / w%, at least 1 w / w%, at least 5 w / w%, at least 10 w / w%, at least 25 w / w%, at least 50 w / w%, at least 100 w / w%, at least 150 w / w%, at least 200 w / w%, at least 250 w / w%, at least 275 w / w%, at least 290 w / w%, at least 295 w / w%, and / or the like. In other embodiments, the concentration may be no greater than 300 w / w%, no greater than 295 w / w%, no greater than 290 w / w%, no greater than 275 w / w%, no greater than 250 w / w%, no greater than 200 w / w%, no greater than 150 w / w%, no greater than 100 w / w%, no greater than 50 w / w%, no greater than 25 w / w%, no greater than 10 w / w%, no greater than 5 w / w%, and / or the like.

[0103] The resulting morphology of the ionic biogel is primarily determined by the mixing sequence of the ionic and gel phases, which influences phase separation and network formation.

[0104] In one embodiment, the components of the ionic phase are added before the gel phase. This approach results in a nucleated system characterized by a stable configuration with isolated conductive or semiconductive polymer domains. For instance, conductive or semiconductive polymers may be combined with ionic liquids prior to the addition of the matrixforming polymer and / or plasticizer. Although salts are described as part of the gel phase, they may be incorporated at any stage, including simultaneously with the conductive or semiconductive polymers during initial mixing.

[0105] The nucleated system typically demonstrates highly efficient and rapid thermoreversibility. However, it may exhibit limited electrical conductivity due to the dispersed, non-percolating nature of the conductive domains.Atty. Ref. No. 0073605-001078

[0106] Conversely, in another embodiment, the ionic phase components are added after the gel phase has been formed or layered, producing a bicontinuous system with percolated networks of conductive or semiconductive polymer. The bicontinuous morphology may form a metastable or unstable configuration, depending on the concentration of the conductive or semiconductive polymers. When the concentration of the conductive or semiconductive polymer is below the spinodal line, the bicontinuous system exhibits rheological characteristics, phase dynamics, and conductivity similar to the nucleated systems described above. Alternatively, when the concentration exceeds the spinodal threshold, the bicontinuous network resists phase transition but can still display semiconducting properties.

[0107] The terms “spinodal line” or “spinodal threshold” herein refer to the boundary within a phase diagram that separates the metastable region from the unstable region during phase separation. Crossing this threshold influences the stability and morphology of the resulting biogel.

[0108] Notably, when the bicontinuous system’s conductive or semiconductive polymer concentration is within a critical range — e g., between approximately 100 and 125 w / w% relative to the matrix-forming polymer — the biogel can simultaneously exhibit semiconducting behavior and phase-transition capability while maintaining an ultra-low storage modulus. This advantageous combination allows the biogel to be both mechanically soft and electronically functional, suitable for applications requiring dynamic switching and stable conductivity.

[0109] Embodiments further relate to methods of using the ionic biogels described above for various practical applications.

[0110] One exemplary application involves integrating the biogel with wearable sensor arrays to enable continuous, on-body measurement of physiological signals. For instance, theAtty. Ref. No. 0073605-001078biogel can facilitate the placement and secure attachment of sensors (e.g., EEG electrodes, bioelectrical sensors, or biochemical detectors) by acting as an adhesive interface that conforms intimately to the skin. Its unique combination of low skin-contact impedance and flexibility allows it to maintain reliable signal acquisition across different hair types, body oils, and skin conditions, thereby enhancing the stability and accuracy of long-term monitoring.

[0111] Beyond neural interfaces, this biogel could be employed in wearable health devices fortracking vital signs, muscle activity, hydration levels, or biochemical markers, making it a versatile platform for personalized medicine and remote patient monitoring.

[0112] The bicontinuous biogel (with more than 100% PEDOT: PSS concentration) shows semiconducting property and can be used as the channel material for organic electrochemical transistor. Therefore, it can be also used as on-site amplification for electrophysiological signals like active EEG or EMG electrodes and biochemical sensors.

[0113] The ionic biogel can be also used as a stimulating gel for a long-term electrical stimulation applicable to various body parts like arm and hand.

[0114] A particularly critical requirement for thermoreversible neural interfaces and other biomedical devices is a controllable gel-sol transition near physiological temperature (~37°C). This property enables the biogel to be rapidly extruded or applied onto the desired body surface, such as the scalp, where it then quickly re-gels to form a stable, conformal interface. The ability to precisely control this transition facilitates minimally invasive and user-friendly applications, especially in scenarios requiring repeated or long-term use. Rheological measurements confirm that the biogel exhibits reversible gel-sol behavior near body temperature, allowing it to adapt dynamically to movements, skin deformation, or environmental changes.Atty. Ref. No. 0073605-001078EXAMPLE

[0115] Below are examples of specific embodiments for carrying out the present invention. The examples are offered for illustrative purposes only, and are not intended to limit the scope of the present invention in any way. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperatures, etc.), but some experimental error and deviation should, of course, be allowed.

[0116] This example demonstrates an ionic biogel comprised of PEDOT: PSS / ionic liquid (ionic phase) and gelatin-glycerol-salt (biogel phase) systems with two types of polymer mixing sequences: 1) nucleated (ionic phases added before biogel phase) with a stable configuration with isolated PEDOT phases and 2) bicontinuous (ionic phases added after biogel phase) with a metastable or unstable configuration (depending on the polymeric concentration) with percolated PEDOT phases (See Supplementary Note 1, presented below). The nucleated systems show highly efficient, rapid thermoreversibility, but are dominated by mobile ion-assisted conduction, whereas the bicontinuous systems (polymeric concentration less than the spinodal line S;) show similar rheological characteristics, phase dynamics, and conductivity as nucleated systems. However, with polymeric concentration more than St, the percolated viscoelastic polymer network resists phase-transition but shows semiconducting properties (summarized in FIG. 45). Interestingly, we could engineer a very small polymeric concentration region (~St~ 100 — 125 w / w% of PEDOT: PSS concentration w.r.t. biogel) with simultaneous semiconducting property and a phase-transition (tan <5 ^1) and ultra-low storage modulus (< 1 kPa) at around ~50°C. Moreover, the bicontinuous systems become a layered heterogeneous system when there is no mixing, highlighting a highly conductive system analogous to a degenerately doped semiconductor. Both ionic-liquid-based, long-term ionic conductivity of the nucleated systemAtty. Ref. No. 0073605-001078and the electrically conductive bicontinuous system enable a reusable, robust neural interface with low skin-contact impedance, irrespective of hair types, maintained over three days to establish a long-term objective assessment of mechanical and electrical stimulations using event-related desynchronization.Materials

[0117] Gelatin from porcine skin powder with gel strength 300 g Bloom Type A, Glycerol 99%, sodium chloride (NaCl), and the ionic liquid 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) with a concentration of 98% (HPLC) and 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf) were purchased from Sigma Aldrich. PEDOT: PSS (PH 1000) in aqueous solution was purchased from Ossila. For PDMS, Sylgard 184 Elastomer Base and its Curing Agent from Electron Microscopy Sciences were used at a 10:1 ratio. Ethylene glycol (EG, anhydrous, 99.8%), choline chloride (ChCl, bioreagent grade), menthol (> 99%), and thymol (> 98.5%) were all obtained from Sigma-Aldrich and used as received without further purification. KCl-based solid electrolyte and Ag / AgCl commercial disposable electrodes were bought from 3M. PVDF-HFP (with a molar mass of Mw = 400,000 g mol-1and Mn = 130,000 g mol-1, respectively) was purchased from Sigma Aldrich. Acetone was obtained from VWR Chemicals BDH Co., Ltd. Poly (ethylene glycol) (PEG) was purchased from Gelest Inc. Conductive EEG pastes AC Cream was secured from Spes Medica.

[0118] Preparation of Biogels

[0119] Non-ionic Biogel

[0120] The non-ionic biogel was prepared by dissolving 0.11 grams of sodium chloride in 1 mL of water. Afterward, 0.75 grams of glycerol were added and mixed, followed by adding and thoroughly mixing 0.5 grams of gelatin. The solution was left for 2 hours so that the gelationAtty. Ref. No. 0073605-001078could occur to result in an amorphous state, and then it was heated in an oven at 80°C for 15 minutes. For storage or later use, the biogel was left at room temperature for around 6 hours to solidify. The biogel could be heated at any time afterward to reacquire its liquid form, showcasing its thermoreversible property (though repeated heating drastically changes the property of this biogel).

[0121] (Nucleated) Ionic Biogel

[0122] The (nucleated) ionic biogel was prepared by dissolving 0.11 grams of sodium chloride in 1 mL of PEDOT: PSS in an aqueous solution, along with adding and thorough mixing of 1 mL of ionic liquid (EMIM - TFSI, EMIM - OTf, hydrophobic and hydrophilic DES). After 5 minutes, 0.75 grams of glycerol were added and mixed, followed by adding and thoroughly mixing 0.5 grams of gelatin. The solution was left for 2 hours to enable gelation in an amorphous state and then heated in an oven at 80°C for 15 minutes. For storage or later use, the resulting (nucleated) ionic biogel was left at room temperature for around 6 hours to solidify. The ionic biogel could be heated at any time afterward to reacquire its liquid phase with high efficiency.

[0123] (Bicontinuous) Ionic Biogel

[0124] The (bicontinuous) ionic biogel was prepared by mixing 0.75 grams of glycerol and 0.5 grams of gelatin along with 0.11 grams of sodium chloride and 1 mL of ionic liquid (EMIM-TFSI). After 5 mins of gelation of gelatin-based organogel, 2.88 ml (or 1.01 - 8.64 ml) of PEDOT: PSS in an aqueous solution was mixed to obtain 100 w / w% (35 w / w % - 300 w / w %) percolated. The solution was left for 2 hours to enable gelation in an amorphous state and then heated in an oven at 80°C for 15 minutes. For storage or later use, the resulting (bicontinuous)Atty. Ref. No. 0073605-001078ionic biogel was left at room temperature for around 6 hours to solidify. The ionic biogel could be heated at any time afterward to reacquire its liquid phase.

[0125] Layered Ionic Biogel

[0126] The layered ionic biogel was prepared by mixing 0.75 grams of glycerol and 0.5 grams of gelatin along with 0.11 grams of sodium chloride and 1 mL of ionic liquid (EMIM-TFSI). After 5 mins of gelation of gelatin-based organogel, 2.88 ml (or 1.01 - 8.64 ml) of PEDOT: PSS in an aqueous solution was dropped (without mixing)' to obtain the 100 w / w% layered ionic biogel. The heterogeneous material was left for 2 hours to enable gelation in an amorphous state and then heated in an oven at 80°C for 15 minutes. For storage or later use, the resulting layered ionic biogel was left at room temperature for around 6 hours to solidify. The ionic biogel could be heated at any time afterward to reacquire its liquid phase.

[0127] Hydrophilic and hydrophobic deep eutectic solvents

[0128] The hydrophilic deep eutectic solvent (DES) was prepared by mixing choline chloride (ChCl) as the hydrogen bond acceptor (HBA) and ethylene glycol (EG) as the hydrogen bond donor (HBD) at a molar ratio of 1:2. The mixture was heated at 100°C under constant stirring at 500 rpm until a homogeneous, transparent liquid was obtained, confirming the successful formation of the DES. For the hydrophobic DES, menthol and thymol were combined at a 1: 1 molar ratio and heated at 60°C with stirring at 500 rpm until a clear and uniform solution was formed.

[0129] PVDF-HFP / PEG Ionic Dielectric

[0130] The PVDF-HFP solution was formulated by dissolving PVDF-HFP pellets in acetone at a mass ratio of 20:3 under continuous stirring at 1,000 rpm and 120 °C until complete dissolution, as previously reported. Once the solution was cooled to room temperature, PEG wasAtty. Ref. No. 0073605-001078incorporated at concentrations of 1 wt%, 2 wt%, 4 wt%, or 6 wt% relative to the total solution volume. The PEG-modified solution was stirred at 1,000 rpm for 24 hours to ensure homogeneity. Subsequently, the solution was spin-coated onto pre-cleaned glass substrates at 1,000 rpm for 30 seconds, followed by vacuum drying at 80 °C to remove residual solvent, resulting in the formation of PEG-PVDF-HFP thin films.

[0131] Organic Electrochemical Device (OECT) Device Fabrication

[0132] OECT devices were fabricated on polyimide substrates by thermally evaporating a bilayer of chromium (10 nm) and gold (90 nm) through a shadow mask to define the source and drain electrodes. The resulting devices had a channel length of 1 mm and a width of 3 mm. Following electrode deposition, (percolated or nucleated) semiconducting ionic biogels were heated to 80°C for 2 minutes and were “painted” over the channel with a tape mask to ensure uniform thickness of 50 pm and lateral dimensions as previously reported. Due to the rapid physical crosslinking property of the ionic biogel (i.e., viscosity increases rapidly under ambient conditions, therefore it becomes practically impossible to spin-coat), painting was chosen over spin-coating. To ensure electrical isolation and channel dimension, the semiconducting layer beyond the defined channel region was precisely trimmed using a scalpel under an optical microscope. Cured and free-standing dielectric PVDF-HFP / PEG 4% (thickness of 50 pm) was then placed on top of the semiconducting channel material. The KCl-based solid electrolyte, along with Ag / AgCl commercial disposable electrodes, was placed vertically on top of the channel / dielectric stacking.Methods

[0133] XPSAtty. Ref. No. 0073605-001078

[0134] XPS experiments were performed using a Physical Electronics VersaProbe III instrument equipped with a monochromatic Al ka x-ray source (hv = 1,486.6 eV) and a concentric hemispherical analyser. Charge neutralization was performed using both low-energy electrons (<5 eV) and argon ions. The binding energy axis was calibrated using sputtered clean Cu (Cu 2p3 / 2 = 932.62 eV, Cu 3p3 / 2 = 75.1 eV) and Au foils (Au 4f7 / 2 = 83.96 eV) as in the previous report. Peaks were charge referenced to the CHx band in the carbon Is spectrum at 284.8 eV. Measurements were made at a take-off angle of 45° with respect to the sample surface plane. This resulted in a typical sampling depth of 3-6 nm, with 95% of the signal originating from this depth or shallower. Quantification was done using instrumental relative sensitivity factors (RSFs) to account for the x-ray cross-section and inelastic mean free path of the electrons. In the homogeneous samples, major elements (>5 atom%) tend to have standard deviations of <3% while minor elements could be significantly higher. The analysis size was ~200 pm in diameter.

[0135] UV-Vis Turbidity Analysis

[0136] UV-Vis spectroscopic measurements were conducted using a Lambda 950 spectrophotometer (PerkinElmer, USA) equipped with a standard photometric detector (STD) and spectra were collected using UV WinLab software (v7.0). For the baseline correction (100% transmittance), the quartz cuvette filled with deionized water was used. Spectra were acquired over the wavelength range from 1000 to 400 nm, with a step of 1.0 nm, acquisition time of 0.2 s per data point, and a spectral bandwidth of 2.0 nm in the UV-Vis region. In the near-infrared (NIR) region, the spectral bandwidth was set to servo slit mode. The detector changes between the photomultiplier tube (PMT) and the lead-sulphide (PbS) detector were set to 860.8 nm, to optimize optical throughput across regions.Atty. Ref. No. 0073605-001078

[0137] The ionic biogel sample was placed into a short pathlength quartz cuvette (1 mm pathlength, P / N: RRPG094 Pine Research, USA) to improve the transmittance of the biogel sample. To perform temperature-dependent measurements, the Versa 20 liquid cuvette holder was interfaced with a Quantum Northwest TCI temperature controller and controlled with the T-App software (vl.52f), which enabled a uniform thermal ramp up to 60°C at a controlled rate of 0.2°C / min. The actual sample temperature was monitored in situ using an immersed Type K thermocouple, with electrical readout via a USB-2001-TC (Measurement Computing, USA) module using DAQami software (v 4.2. IfO) to ensure precise thermal feedback and data acquisition fidelity.

[0138] Particle Size Analysis

[0139] Particle size analysis was performed using a Mastersizer 3000 (Malvern Panalytical; Netherlands) with the HydroMV dispersing cell (125ml). Light sources of 632 nm [He-Ne Laser] and 470 nm [LED] were used for data collection. Deionized water was used as the dispersant for the testing. Data collection time was 10 seconds for each measurement. Five measurements were taken for each aliquot of the sample tested.

[0140] Raman Spectroscopy

[0141] All Raman spectroscopy was acquired using a Horiba LabRam HR Evolution equipped with a 785 nm laser (Crystal Laser, DL-785-120-SO) coupled through a 50x LWD lens (NA 0.5) with an incident laser power of 30 mW (with laser threshold test performed on the samples). The spectrometer was equipped with a 150 pm confocal hole, a 300 gr / mm grating, and a Synapse BIDD Si-array detector (1024 × 512 pixels), and calibrated using the Raman response of a chip of single-crystal silicon. The temperature stage was a Linkam HFS600. PointAtty. Ref. No. 0073605-001078maps were acquired after waiting a minimum of 3 minutes after the temperature stage reached the desired setpoint temperature.

[0142] FTIR

[0143] Infrared spectra were collected in attenuated total reflection (ATR) geometry on a Bruker Vertex 70 spectrometer equipped with a liquid nitrogen-cooled mid-band mercury cadmium telluride (MCT) detector and a Harrick Diamax ATR accessory with a heatable solid sampling adapter. A background (bare crystal) and sample spectrum was collected after 10 min of equilibration at each temperature. A total of 400 scans were averaged at 4 cm-1resolution, with the absorbance calculated by referencing to the clean bare diamond ATR crystal.

[0144] AFM

[0145] The peak force tapping-quantitative nanomechanical mapping experiments were performed in air on a BiosScope Resolve (Bruker). RTESPA150 (Bruker) probes were used with a nominal tip radius of 5 nm and a spring constant of 6 N / m. Scans over 20 pm by 2 pm were performed with a probe vibration frequency of 2 kHz, peak force amplitude of 150 nm, 512 samples / line, and a scan rate of 0.35 Hz. Images were analyzed with NanoScope Analysis v.3.

[0146] WAXS

[0147] The wide-angle X-ray scattering (WAXS) experiments were performed on a laboratory beamline (Xeuss 2.0 HR®, Xenocs, France) using a GeniX3D microfocus sealed tube (copper) beam source with X-ray wavelength of 1.54 A and power settings of 50 kV and 0.6 mA. A Dectris Pilatus3 R200K® detector was used with a sample-to-detector distance of approximately 0.15 m. The scattering experiments were collected at 27, 40, 50, 60, and again at 27°C using silicon scatterless slits for collimation (1.2 and 0.8 mm). The 2D images were integrated using “X-ray Scattering Analysis and Calculation Tool” (XSACT vs 2.6) softwareAtty. Ref. No. 0073605-001078from Xenocs to convert 2D images into one-dimensional scattering data of scattering intensity I(q) (in arbitrary units) versus 2theta. Each image was produced by collecting and summing three vertical images (300 seconds each with line eraser mode). Line eraser mode is a function designed by the manufacturer to allow images to be overlapped to correct for non-sensitive areas in the summed 2D images caused by the detector (built from multiple sensor modules tied together).

[0148] uCT Imaging

[0149] High-resolution microcomputed tomography (pCT) was employed to non-destructively visualize and quantify the internal microarchitecture of the ionic biogels, enabling differentiation between nucleated and bicontinuous morphologies. Biogel samples were prepared in cylindrical polyethylene tubes to prevent dehydration and movement during scanning.

[0150] pCT images were obtained on a Zeiss Xradia 620 (Germany). The voltage used was 70 kV and the power was 8.5 W with 3001 projections and a 1-second exposure. The LEI filter was used. The reconstruction was obtained from the Scout and Scan Software (Zeiss, Germany). The voxel size of the image was 1.3 pm.

[0151] Biocompatibility Test

[0152] Hydrogel samples were cut into circular films with a 10 mm diameter and added to PBS to prepare hydrogel extracts, and 1.0 mL of the extract was put into a 24-well plate for UV irradiation. For each well containing hydrogel extract, 2* 104MCF-10A was added, and the proliferation medium was supplemented to 1.0 mL. For the wells without material as the control group, 2><104MCF-10A was also added and the proliferation medium was supplemented to 1.0 mL. The 24-well plate containing MCF-10A and the extract was incubated in a cell cultureAtty. Ref. No. 0073605-001078incubator, and 200 pF of proliferation medium was added to each well every two days. The proliferation of MCF-10A on the hydrogel extract on days 1 and 2 after co-culture was determined using MTT. After adding the FDA, the staining results were observed using a fluorescence microscope.

[0153] Seeback Coefficient Measurement

[0154] Seeback coefficient measurement was performed using a custom-designed setup. Two copper blocks, connected to circulating water as heater / chiller units, were utilized to generate a temperature gradient across the samples in a planar configuration. One of the copper blocks maintained a continuous flow of water at a temperature of 9°C, whereas the other block was subjected to incremental cooling and heating and maintained at varying temperatures through a chiller from 0°C to 30°C. Two thermocouples were attached to the edge of the samples on two sides to monitor real-time temperature changes. The voltage change was recorded after a stable temperature was reached.

[0155] DSC Measurement

[0156] The thermal properties were measured by differential scanning calorimetry (Netzsch DSC 214, Germany) under an Ar atmosphere with a heating rate of 2°C / min.

[0157] Mechanical Testing

[0158] General Procedures'. All mechanical and adhesive testing was conducted on an Instron J5966 testing frame (Instron, Binghamton, NY, USA) with a 1 kN load cell and utilizing Bluehill Universal mechanical testing software (Instron).

[0159] Compression Testing: Compression testing between parallel plates (Instron) was carried out on hydrogel specimens with a diameter of 8 mm and a thickness of 1 mm to 90% strain at a strain rate of 1.3 mm / min. Initial modulus and peak stress at 90% strain wereAtty. Ref. No. 0073605-001078calculated from the stress profile over the initial 10% strain and the maximum stress value, respectively.

[0160] Tensile Testing: Tensile testing was carried out using pneumatic grips (Instron) on hydrogel samples (length x width x thickness: 3 cm x 1 cm x 1mm) at a strain rate of 50 mm / min. Initial tensile modulus, peak stress, and peak strain were calculated from the stress profile over the initial 10% of strain and the maximum stress and strain values, respectively.

[0161] Adhesive Testing: Lap shear adhesive testing was carried out using pneumatic tensile grips. Strips of porcine tissue (1 cm width) were adhered in a lap configuration with an adhesive area of 1 cm2and placed within the tensile grips (with the adhered region facing outside of the gripped area). The tensile force was then applied at a rate of 5 mm / min until adhesive failure, with the maximum adhesive force recorded. 90° adhesive peel testing was carried out by first gluing a porcine tissue strip (1 cm width) to a flat acrylic plate, which was then attached to the bottom compression plate of the mechanical testing frame using vice grips. Another strip of porcine tissue was adhered to this first piece using the appropriate hydrogel adhesive to create an adhesive area of 1 cm2. The other, free end of the second strip was then gripped by the top pneumatic grip of the testing frame, after which a tensile force was applied to the top to achieve the 90° peel, with adhesive force measured as above.

[0162] Rheological Testing

[0163] General Procedures: All rheological testing was conducted on a DHR-2 rheometer (TA Instruments, New Castle, DE, USA) using TRIOS software (TA Instruments) in a 20 mm parallel plate configuration (sandblasted plate faces) with a Peltier plate to control the temperature. Hydrogel samples with a diameter of 20 mm and a height of 1 mm were used at 25°C unless stated otherwise.Atty. Ref. No. 0073605-001078

[0164] Shear Sweep: Shear sweeps were first conducted to establish the linear response region from 0.01 to 1,000% strain at a frequency of 1 Hz.

[0165] Frequency Sweep: Frequency sweeps were conducted from 0.1 to 100 Hz within the linear response region (0.05% strain).

[0166] Temperature Sweep: Temperature sweeps were conducted in 3 phases: 1) an initial ramp from 25 to 60°C at a rate of 5°C / min, 2) a cooling ramp from 60 to 25°C at a rate of 5°C / min, and 3) a recovery interval at 25°C for 900 s (all at 1 Hz and 0.05% strain).

[0167] Cyclical Recovery Test: The above 3 phases were repeated over 20 successive cycles.

[0168] Temperature - Adhesion Test: Tensile adhesion tests were performed by placing the ionic biogel between two skin phantoms, which were strongly adhered to the aluminium plates at both ends. The ionic biogel, along with the skin, was pre-heated to different temperatures from 30 to 60°C and returned to room temperature (25°C). After a holding time of 5 minutes at room temperature, the axial force and displacement were noted at each cycle to evaluate the temperature-dependent interfacial adhesion stiffness and toughness.

[0169] Stimulation Procedure

[0170] A 26-year-old male human subject participated in the stimulation experiment. During the experiment, the subject was comfortably seated in a chair. The electrical stimuli were delivered via a set of 2x8 gel-based electrodes (FIG. 36). Each electrode with a diameter of 1 cm was replaced with the reported ionic biogel to enhance conductivity. The electrodes were positioned along the medial portion of the right upper arm, just beneath the short head of the biceps brachii, targeting the area near the median and ulnar nerves. This placement aligned with the way that extended from the centre of the armpit to the inner side of the elbow (medialAtty. Ref. No. 0073605-001078epicondyle of the humerus), ensuring placement over the nerve pathways located below the skin. To deliver the electrical stimuli via a specific pair of electrodes (FIG. 36), a custom-built MATLAB interface to control a switch matrix (Agilent Technologies, Santa Clara, CA) for electrode pair selection was used. The MATLAB interface was also used to configure the stimulation parameters of the stimulator (STG4008, Multichannel Systems, Reutlingen, Germany). Specifically, single biphasic rectangular pulses (FIG. 6) were delivered to selected electrodes with a pulse width of 200 ps and a stimulation frequency of 150 Hz. To indicate the force evoked by stimulation, the subject's right hand was placed on a force load cell (LCM201-100N, Newark Electronics, Chicago, IL) with a sampling frequency of 1,000 Hz, allowing the subject to apply varying levels of pressure with the index finger in response to the force evoked by stimulation as in the previous report.

[0171] A grid search was initially performed to identify a pair of electrodes that could effectively induce flexion in at least one finger, while minimizing wrist movement and avoiding any discomfort. Once identified, this electrode pair was used for subsequent experiments.Multiple 3-s stimulation trials were conducted, with the pulse amplitude gradually increased until the subject reported discomfort. The measured forces during the plateau period were averaged to indicate the force evoked by stimulation. The evaluation of the long-term usability of the reported ionic biogel involved a series of experiments over the span of one week, specifically on Days 1, 2, 4, and 7.

[0172] Electrochemical Measurements

[0173] Electrochemical Impedance Spectroscopy (EIS)

[0174] Electrochemical impedance spectroscopy was performed using a MetroOhm Autolab Potentiostat electrochemical workstation, with thin ionic biogel on gold / polyimideAtty. Ref. No. 0073605-001078substrates serving as the working electrodes. A silver / silver chloride (Ag / AgCl) electrode served as the reference, with a platinum electrode as the counter electrode. The three-electrode setup was submerged in a solution consisting of potassium ferricyanide(III) (0.01 M), potassium hexacyanoferrate(II) trihydrate (0.01 M), over a frequency range spanning from 100 kHz to 1 Hz, using a sinusoidal perturbation of 10 mV superimposed on a 0.1 V DC bias. The resulting impedance spectra were analyzed using the MATLAB 2024b software. Capacitance and resistance values were extracted through equivalent circuit fitting by using a simplified Randles model for nucleated and a dual-Randles model for Bicontinuous systems, which were further normalized by the geometric dimensions.

[0175] Charge Injection Capacity

[0176] The charge injection capacity (CIC) is a critical parameter that ensures the safety of electrodes during stimulation. It is defined as the maximum charge density that an electrode can inject without exceeding the water electrolysis threshold. Exceeding these thresholds can result in electrode damage, the generation of toxic byproducts, or tissue damage. Safe stimulation relies on maintaining the maximum cathodal voltage (Emc) within the electrochemical water window, typically between -0.6 V and 0.8 V, as previously reported.

[0177] Voltage-Transient Analysis: The CIC is derived from voltage transients during a biphasic current pulse. The cathodal and anodal pulse widths (tc, ta) and respective currents (ic, ia) determine the injected charge:Qinj=^Cic(t)dt + ^aia(t)dt. (1)

[0178] The maximum cathodal excursion potential (Emc) is measured immediately after the pulse and corrected for access voltage (Va) due to series resistance:Atty. Ref. No. 0073605-001078^mc ^transient ^a- (2)

[0179] Charge Injection Limits: The Charge Injection Capacity (CIC) is the maximum charge density that can be injected without the onset of water reduction (cathodal limit) or oxidation (anodal limit):CIC = (3)Aeff

[0180] where Aeff is the geometric surface area of the electrode.

[0181] Electrochemical Window Constraints: Safety requirements indicate: EmA 0.6 V and Eina<0.8 V. The frequency ( / ) of stimulation is inversely related to the total period (T) of the waveform, which includes both the cathodal (tc) and anodal (ta) pulse widths, as well as the interphase delay (tip):r =), <4)

[0182] where T = tc+ ta+ tip. Here, cathodal and anodal pulse widths are the same tc= ta= t, and inter-phase delay tip= 10 ms is kept constant. Therefore, a shorter pulse width signifies a higher frequency withf1= - 2t+1 -0 -ms ■ (v5)7

[0183] OECT Measurements

[0184] Transfer and Output Curves

[0185] All transfer and output characteristics for OECT measurements were performed using a Keysight B1500A parameter analyser under ambient conditions (and at higher temperatures for studying temperature-dependent properties). The voltage sweep rate was maintained at 8 mV / s unless stated otherwise.

[0186] Bandwidth MeasurementsAtty. Ref. No. 0073605-001078

[0187] High-speed, drain-current measurements (with a bias VD= —0.7 V) were performed using a PZ2100A high-density precision source measurement unit (SMU) mainframe with PZ2121A high-speed SMUs, whereas gate voltages were applied from a RIGOL DG4102 Waveform Generator.

[0188] Mobility Measurements

[0189] The charge carrier mobility z) of the biogel semiconductor during OECT operation was determined by evaluating the hole transit time (rh), following previously established protocols. In this method, constant gate currents (lg) were applied to the device while maintaining a fixed drain-source bias (I / p = - 0.1 V) with a gate compliance of VG= 0.6 V. The resulting transient response of the drain channel current was recorded to extract Thusing dip 1G= <6

[0190] The mobility was then calculated using the relation:

[0191] where L denotes the channel length.

[0192] Electrical Measurements

[0193] Electrical Impedance

[0194] Electrical impedance spectra were taken using the Hioki IM 3536 - 01 LCR Meter under ambient conditions (or at higher temperatures for studying temperature-dependent properties). The stability tests of the Bicontinuous and Nucleated ionic biogels in the sandwich configuration were performed over 21 days, with the electrical impedance spectra measured each day under ambient conditions.

[0195] Electrophysiology MeasurementsAtty. Ref. No. 0073605-001078

[0196] The EMG and EEG signals were measured using the BioAmp Data Acquisition system (AD Instruments).

[0197] Two Terminal Measurements

[0198] Two-terminal I-V measurements were performed using a Keithley 2401 Source Meter.Results

[0199] Rheological Characterizations

[0200] A requirement for thermoreversible neural interfaces is a controllable gel-sol transition near physiological temperature (~37°C) to enable rapid extrusion onto the scalp, followed by efficient and reversible re-gelation to establish conformal, stable adhesion to the skin surface, which can be experimentally validated by rheological measurements. Both nucleated and bicontinuous (< St) systems show phase-transition and thermoreversibility, whereas bicontinuous (> SL) fails to show phase-transition due to its percolating PEDOT polymeric network (here, Stis the polymeric concentration threshold of 100-125 w / w % PEDOT: PSS w.r.t. biogel) (FIG. 6). For the nucleated system (35 w / w%), the loss tangent (tan 8 = G" / G', where G" and G' are the loss and the storage modulus, respectively) transitions from tan 8 = 0.1 (and ~1.6 kPas) at room temperature to tan 8 ~ 2.5 at high temperature (50°C) and then back to tan 8 = 0.2 at room temperature in 15 mins (FIG. 7) (Supplementary Note 2, presented below). Similarly, the bicontinuous system (< 5): 50, 75 w / w%) shows a phase transition from tan 8 = 0.6, 0.8 at room temperature to tan 8 = 2 at 60°C and then back to tan 6 = 0.9, 1.1 at room temperature in 15 mins (FIG. 8). However, for bicontinuous (>St100, 200, 300 w / w%), the loss tangent reaches a maximum of tan 8 » 1, 0.8, 0.4,Atty. Ref. No. 0073605-001078respectively, with only 100 w / w % barely achieving a gel-sol transition and thermoreversibility, but not as efficiently as nucleated or bicontinuous (< S() (FIG. 9). With the same PEDOT polymeric concentration, the nucleated system of 100 w / w% shows a clear phase-transition of tan / ) ~ 2.8, contradictory to the bicontinuous system (FIG. 10). In summary, for bicontinuous (< Si = 100 w / w %) phase-transition occurs with low thermal hysteresis (A tan 8 ~ 50 % and A Viscosity ~ 20 %) after a thermal cycle (heating at 5°C / min, cooling at 5°C / min, and isothermal for 15 mins), whereas bicontinuous (> SL= 125 w / w %) doesn’t have a phasetransition and therefore low thermal hysteresis (A tan 8 ~ 50 % and A Viscosity - 20 - 40 %). As for bicontinuous (St= 100, 125 w / w %), it just attains a phase-transition, along with a percolated PEDOT polymeric network (FIG. 11). The emergence of a percolated polymeric network imposes significant viscoelastic constraints on thermoreversible behaviour, as long-range percolation induces slow entangled chain dynamics with high relaxation times and kinetic barriers for network reorganization. In this regime, thermal hysteresis increases due to delayed disassembly of the network upon heating, reflecting the energetic cost of overcoming entangled configurations and disentangling topological constraints. However, at a highly dense percolation network where the polymeric network forms a quasi-permanent scaffold, the system fails to undergo a gel-sol transition due to the irreversible entrapment of polymer chains within a rigid framework. Consequently, the apparent hysteresis diminishes not due to enhanced reversibility, but rather from the collapse of thermoresponsive behaviour itself, underscoring a critical tradeoff between thermoreversibility and phase percolation. Thermoreversibility becomes more efficient with insoluble ionic liquids as it facilitates phase-separation; therefore, hydrophilic Deep Eutectic Solvent (DES) shows a much higher thermal hysteresis of A tan 8 ~ 400 % andAtty. Ref. No. 0073605-001078A Viscosity ~ 70 % compared to EMIM-TFSI for nucleated 35 w / w% (FIG. 12). Moreover, hydrophobic DES remains in the gel phase due to dense hydrogen bonds; on the other hand, soluble EMIM-OTF always remains in the solution phase with tan 8 > 1. Along with the type of ionic liquid, both variations in ionic liquid concentrations (keeping PEDOT: PSS concentration constant) and in combined concentrations of PEDOT: PSS and ionic liquid influence the rheological and tensile properties of the nucleated system, even with quasistatic heating. The phase-temperature diagram (during heating) for the nucleated system shows that there is a gradual variation of viscosity-temperature across different concentrations, suggesting a stable nucleated configuration without any onset of spinodal decomposition through percolated morphology. In contrast, for the bicontinuous system, there is a sharp decrease in viscosity (<500 Pas) for PEDOT concentration less than 125 w / w % to enable flow. A similar trend is also observed during the cooling cycle with some loss of thermoreversibility. An interesting phenomenon emerges when 20 thermal cycles are deployed to evaluate the time constant of each isothermal relaxation cycle for five different biogel systems (bicontinuous 100 w / w %, bicontinuous 50 w / w %, bicontinuous 35 w / w %, nucleated 35 w / w%, and non-ionic biogel). The nucleated system shows a highly efficient thermoreversibility throughout the cycles with a time constant of ~1.6 mins during the isothermal cycle of storage modulus (FIG. 13), whereas the non-ionic biogel7shows a time constant of -5 mins. The bicontinuous 100 w / w % shows a decrease of the time constant from -12 mins to -1.6 mins (similar to nucleated system) after 20 cycles, whereas its time constant of loss modulus during the isothermal cycle sharply decreases (linearly) till the 11thcycle, then it saturates without showing any relaxation (FIG. 13). Even with a decrease in PEDOT: PSS concentration in the bicontinuous system, the time constant for 35 w / w% (slowly - 0.25 min / cycle) and 50 w / w% (sharply - 0.5 min / cycle) decreases withAtty. Ref. No. 0073605-001078cycles for storage modulus (FIG. 14). Similarly, for loss modulus, the time constant decays faster with an increase in concentration: 0.6 min / cycle (100 w / w%) to 0.1 min / cycle (35 w / w%) (FIG. 14)

[0201] UV-Vis Turbidity Characterizations

[0202] In LLPS, UV-Vis techniques have been effectively employed to observe the increase in optical density (turbidity) and its correlation to rheological signatures of phase dynamics. Spectro-rheological framework provides a powerful, non-invasive window into therm oreversible behaviour, bridging optical response and rheological state with network connectivity and its hysteresis. The nucleated ionic biogels exhibit classic LLPS behaviour upon heating. UV-Vis temperature sweeps show a sharp onset of turbidity at the critical cloud point, which reverts upon cooling — indicating reversible, entropy-driven de-mixing akin to protein condensate behaviour in biochemical LLPS systems (FIG. 15). This turbidity correlates with the nucleation of micron-scale PEDOT droplets, as confirmed by optical microscopy (FIGS. 1 and 3), rheology (FIGS. 6-14), and diffraction. In contrast, bicontinuous ionic biogels show no turbidity analogous to VPS, confirming the presence of large, percolated viscoelastic networks and exhibiting pronounced UV-Vis absorbance hysteresis upon heating and cooling (FIG. 15). For nucleated systems (35 w / w% and 38 w / w%), the UV-Vis absorbance is observed during heating from room temperature to 60°C (FIG. 16)and during cooling to room temperature (FIG. 16). The temperature response of the nucleated system reflects an onset of turbidity at ~37°C, where the absorbance of - 0.9 a.u. jumps to -1.3 a.u. within a AT of ~5°C, reaching a highest absorbance of -1.4 a.u. at 60°C, then returns to an absorbance of -1 a.u. at room temperature (FIG. 17). Similarly, for bicontinuous (St= 50 w / w %), the absorbance increases from -1.2 a.u. at room temperature to -1.75 a.u. at 60°C and returns to - 1 a.u. absorbance at room temperatureAtty. Ref. No. 0073605-001078(FIG. 18). In contrast, for the bicontinuous system with 100 w / w %, the absorbance decreases from -3 a.u. at room temperature to ~1.4 a.u. at 60°C, further decreasing to -0.5 a.u. at room temperature (FIG. 19). The thermal hysteresis of -85% in UV absorbance for 100 w / w % bicontinuous strongly correlates with the thermal hysteresis of A tan 6 - 140 % in rheology. Similarly, for other nucleated and bicontinuous systems, the strong correlation between thermal hysteresis and the rheological parameters (e.g., tan 8 and viscosity) reflects that optical and mechanical properties are governed by the same underlying (reversible or irreversible) phase dynamics during thermal cycling (FIG. 20). In nucleated systems, isolated PEDOT-rich droplets minimize surface area and thus the interfacial energy is not reflected in the Differential Scanning Calorimetry (DSC) compared to its melting enthalpy due to the gelatin matrix and mixing enthalpy (FIG. 21), whereas in bicontinuous ionic biogels, the phase morphology evolves into an extended percolated PEDOT network with a large interfacial area. This structural arrangement introduces a distinct interfacial enthalpy contribution (along with mixing and melting enthalpy as in nucleated systems) (FIG. 22). Therefore, the enthalpy of bicontinuous systems arises not solely from mixing (30 J / g) or melting (44 J / g), but from interfacial energy (27 J / g) associated with the curved and sharp boundaries between the ionic and biogel phases, confirming the enthalpy-dominated thermodynamics for bicontinuous systems compared to the entropy-dominated thermodynamics for nucleated systems (FIG. 23).

[0203] Electrical Characterizations

[0204] In phase-separated ionic biogels, the thermodynamics-driven phase morphology plays a pivotal role in determining charge transport pathways. Nucleated systems, in which the conducting PEDOT phase forms isolated droplets within a continuous biogel matrix, exhibit predominantly ionic conductivity. In contrast, for bicontinuous systems with polymericAtty. Ref. No. 0073605-001078concentration equal to or greater than 100 w / w%, the percolated semiconducting PEDOT polymeric network spans the biogel matrix, leading to enhanced hole conductivity (FIG. 24). With the layered structure, the hole conductivity increases drastically, making it comparable to IL-based PEDOT: PSS systems. To validate the semiconducting property of ionic biogel due to polymeric phase percolation, organic electrochemical transistors (OECTs) are deployed and characterized (FIG. 25). Only bicontinuous > SL= 100 w / w% with extended percolated PEDOT, as shown in previous characterizations such as rheology and turbidity, shows a semiconducting nature. On the other hand, nucleated systems and bicontinuous <= 100 w / w% result in no OECT performance due to the lack of charge transport in the channel layer, whereas layered systems show a highly doped semiconductor with no gating. By leveraging the stimuli-responsiveness in bicontinuous gels > St, the storage modulus can be modulated by temperature, achieving sub-kilopascal mechanical compliance (for St= 100 w / w%) and liquidlike rheological parameters. Such physical crosslinking and stimuli-responsiveness of the ionic biogel allows an active control of temperature (from 25°C to 60°C). The electrical conductivity (or modulus) for bicontinuous 200 w / w% increases (or decreases) from 25 S / cm (storage modulus of 22 kPa, Young’s modulus of 10 kPa) to 38.5 S / cm (storage modulus of 3 kPa); similarly, the conductivity for bicontinuous 100 w / w% achieves 7.7 S / cm with a storage modulus of 1.2 kPa at 60°C to enable the gel-sol transition as a highly-viscous liquid. This typically breaks the flow-conductivity trade-off using an active control of temperature. In passive, ambient conditions, the total conductivity and volumetric capacitance of the layered (100 w / w%) system are 140 S / cm and 8.5 F / cm3, respectively. In comparison, for nucleated 100 w / w% and bicontinuous 50 w / w%, the conductivity gets as low as 5.2 mS / cm and 40 mS / cm, respectively, but the volumetric capacitance remains similar (~35 F / cm3and 45 F / cm3, respectively) (FIG. 26).Atty. Ref. No. 0073605-001078The high volumetric capacitance is a strong indicator of an ionic conductor, which can be confirmed by the electrochemical impedance spectra of the nucleated system (100 w / w%) reaching ~ -70° phase at low frequency (< 1 kHz) to reflect an ionic behaviour. In comparison, the bicontinuous system (100, 200 w / w%) shows ~ 0 to -10° phase, reflecting dominance of electronic conductivity over ionic (FIG. 27).

[0205] The OECT with bicontinuous 100 w / w% and 300 w / w% as the active channel material exhibits a temperature-controlled normalized (by channel width) transconductance of 2.28 mS / mm (storage modulus of 750 Pa, at 100°C) and 15.5 mS / mm (storage modulus of 13 kPa, at 60°C) respectively, approaching those of traditional semiconducting hydrogels and polymers, while maintaining a storage modulus at least ~l-3 orders lower than the state of the art chemically crosslinked hydrogel. Due to the gel-sol transition of bicontinuous 100 w / w%, we could barely achieve a liquid-like tan 6 ~ 1 and a viscosity of 18 Pa s with a normalized transconductance of 1.7 mS / mm. The high conductivity of the layered structure is reflected in the linear ohmic-like transfer characteristics with a high current of -200 mA and poor to no gate electrostatic control, analogous to a highly-doped p-type semiconductor property (with almost no gating) at -0.9 V drain bias. On the other hand, for nucleated (200 w / w%) (FIG. 28) and bicontinuous systems with polymeric concentration of less than 100 w / w%, the drain current and leakage gate current are of similar order without any gating or standard OECT operation.However, when the polymeric concentration reaches 100 w / w% for bicontinuous systems, the percolated PEDOT phase displays semiconducting nature symbolized with an on-current of |ID| ~ 1.7 mA, improved gate electrostatic control with a low gate current of |IG| - 0.01 mA, and a peak transconductance of 3 mS at around gate voltage of - 0.17 V (FIG. 29). The on-current (and peak transconductance) of the OECT increases to 19 mA (28 mS) with the increase inAtty. Ref. No. 0073605-001078concentration for bicontinuous systems from 100 w / w% to 300 w / w% (FIG. 30). The figure of merit [ / rC*] of the channel material (and on-off ratio of the OECT) increases from 0.8 F cm'1V1s'1(I on / Ioff= 17) to 8.4 F cm'1V1s'1(I on / loff = 187) with the increase in concentration from 100 w / w% to 300 w / w% (FIG. 31). The mobility of the semiconducting ionic biogel increases from 0.006 cm2V1s'1to 0.043 cm2V1s'1with the increase in concentration from 100 w / w% to 300 w / w% in the bicontinuous system, as measured using constant gate current (FIG. 32). The relatively modest hole mobility and figure of merit, when compared to state-of-the-art semiconducting hydrogels, can be attributed to the fact that the investigated concentration regime represents the morphological transition point — marking the initial emergence of a percolated, electronically conductive network from an otherwise thermoreversible, ionically dominated phase. The peak transconductance (and on-current) of bicontinuous 300 w / w% and 100 w / w% increases with the increasing temperature with a slope of 0.1 mS / K (0.07 mA / K) and 0.02 mS / K (0.01 mA / K) (FIG. 33). The Seebeck coefficient of nucleated systems decreases drastically from ~21 mV / K to 1.25 mV / K with the increase in concentration from 35 w / w % to 100 w / w%, as conductive PEDOT fillers suppress the Soret-induced ionic gradient and the thermogalvanic potential (FIG. 34) (Supplementary Note 2, presented below). A similar trend is observed for the bicontinuous system, where the Seebeck coefficient decreases from 2.2 mV / K to 0.02 mV / K with the increase in concentration from 100 w / w% to 300 w / w%. The temperature-responsive adhesion and room temperature Young’s modulus (~10 kPa) of the bicontinuous system (irrespective of PEDOT: PSS concentration) can be attributed to the inherent properties of the biogel matrix. The properties such as compressibility, water retention, water vapour transmission, and self-healing of nucleated systems can also be attributed to the biogel matrix.

[0206] Electrophysiology CharacterizationsAtty. Ref. No. 0073605-001078

[0207] The thermoresponsive and mixed ionic-electronic conducting properties of the ionic biogel ensure stable, high-quality, long-term signal acquisition and reliable stimulation, even with different hair types or hair oils. A total of 8 subjects were chosen with different hair types and oils (with one subject without showering throughout, resulting in accumulation of hair oils) for performing different EEG experiments - open and closed eyes, and mechanical (or natural) vibration over 3 days with the same electrodes containing nucleated (n = 8), bicontinuous (n = 8), and either commercial (n = 3) or non-ionic biogel (n = 5) placed on Cl, Cz, and C2 respectively - validating the reusability. In another experiment, one subject is electrically stimulated over the ulnar nerve using a wearable stimulator array over 7 days, with EEG simultaneously recorded (FIG. 36). The skin-contact impedance of bicontinuous (100 w / w%) and nucleated (100 w / w%) remains around 1.6 kQ cm2at 1 kHz (averaged over 3 days) across all the subjects, whereas the commercial gel has > 100 kQ cm2and the state-of-the-art non-ionic biogel performs similarly with bicontinuous and nucleated for some subjects but has >10 kQ cm2for other subjects with more dense hair (FIG. 37). The skin-contact impedance across days (averaged over subjects) shows that the non-ionic biogel performs similarly to nucleated and bicontinuous, with around 2 kQ cm2on day 1 but increases to 40 kQ cm2on day 2 and 20 kQ cm2on day 3. A similar trend is shown for the commercial electrode, with impedance increased from 6 kQ cm2on day 1 to 64 kQ cm2on day 3 (FIG. 38). The electrical impedance at low frequency (4 Hz) shows a stable value of 54 kQ ± 13 kQ over 15 days for bicontinuous 100 w / w%, whereas the nucleated system shows a stable value of 56 kQ ± 16 kQ. An increase in EEG power amplitude during the closed eyes state is observed compared to the open eyes state using both (FIG. 39) bicontinuous and (FIG. 40) nucleated-based electrodes over three days. This is also validated with the onset of alpha wave power after the 57thsecond, which marks theAtty. Ref. No. 0073605-001078closing of the eye for subjects 3 and 4 over days 2 and 3. The efficacy of the ionic biogel electrode is demonstrated through ERD in the recording of neural responses associated with motor cortex activities during mechanical or natural sensation. The EEG power spectrum at Cl and Cz during sensory mechanical vibration (using a vortex vibrator of 50 Hz) reveals an onset of ERD: a reduction in beta power amplitude on day 2 (p < 0.01) and day 3 (p < 0.001) using both nucleated and bicontinuous electrodes (FIG. 41).

[0208] ERD has been known to occur during hand or finger movement, which is also consistent with mechanical vibration. However, to the best of our knowledge, no prior studies have correlated ERD with haptic sensations induced by TENS of the ulnar nerve. The perceived sensation is simultaneously recorded using a force sensor, with EEG data collected using three self-balancing electrodes (with geometry optimized using simulation) at Cz, Cl, and C2 through the hair. A significant challenge in EEG recordings during simultaneous electrical stimulation is the introduced artifacts, particularly charging artifacts resulting from current flow through the body, which can produce high-amplitude voltages (tens of millivolts range) at the scalp and contaminate the EEG signal (in microvolts range). By positioning the ground electrode along the cervical region and ulnar nerve pathway rather than behind the ear, these artifacts are reduced from approximately 40 mV to 4 mV. The artifacts are further reduced by sequential postprocessing methods such as empirical mode decomposition (EMD), bandpass / notch filters, and downsampling. The artifact removal is generally performed using Independent Component Analysis (ICA) to leverage the statistical independence of multiple channels. However, ICA’s performance is restricted as the number of electrodes is only two in this work. Therefore, EMD is utilized to decompose the signal into several intrinsic mode functions (IMFs) with the first mode corresponding to the stimulation artifacts. Similar to mechanical stimulation, ERD is alsoAtty. Ref. No. 0073605-001078observed during electrical stimulation, which is marked by a reduction of power in the alphawave, averaged across trials for all amplitudes (FIG. 42). Different frequencies (5-500 Hz) of electrical stimulation (of amplitude of 3.7 mA) are elicited to record the change of alpha power in the EEG during stimulation (FIG. 43). This power attenuation and its spectrum across different frequencies persist on day 7 (FIG. 44).Conclusion

[0209] This example successfully demonstrated that precise control over polymer mixing sequences and concentrations in a PEDOT: PSS-based ionic biogel enables integrating thermoreversible mechanical adaptability with sustained electrical conductivity and semiconductivity. The nucleated and bicontinuous morphological strategies reveal distinct but complementary advantages: nucleated morphologies provide rapid, hydration-independent thermoreversibility ideal for ionic conduction, and bicontinuous morphologies enable semiconductivity combined with thermoresponsive behaviour within a carefully tuned concentration regime. By leveraging thermodynamic insights inspired by liquid-liquid phase separation in biological systems, we have achieved transient yet stable percolated networks of PEDOT-rich phases capable of reversible transitions.Supplementary Note 1

[0210] Thermodynamics and Kinetics of Ionic Biogel

[0211] At room temperature, mixing all the components of the ionic biogel (either nucleated or bicontinuous) and allowing the mixture to stand for 1-2 hours initially results in a kinetically restricted amorphous gel for both systems. These gels comprise two distinct polymer networks: the PEDOT: PSS / ionic liquid network (Network A - ionic phase) stabilized by electrostatic interactions, and the gelatin / glycerol / salt network (Network B - biogel phase)Atty. Ref. No. 0073605-001078stabilized by hydrogen bonding (FIG. 4). In the ionic system (PEDOT: PSS / EMIM-TFSI), the ionic liquid (EMIM-TFSI) functions as a strong plasticizer, profoundly influencing the electrostatic interactions between the PEDOT and PSS chains. The EMIM+cations and TFSI anions intercalate between the PEDOT and PSS chains, effectively screening the Coulombic attractions and reducing the electrostatic binding energy. This screening leads to a softer polymeric backbone with extended hole delocalization. Concurrently, the biogel phase (gelatinglycerol -salt) hydrogel matrix is stabilized through an extensive hydrogen-bonding network. Gelatin forms triple-helical structures connected via hydrogen bonds between peptide backbone amide groups. The addition of glycerol introduces multiple hydroxyl groups capable of forming hydrogen bonds with both gelatin and water molecules, enhancing the stretchability and reversibility of the gel-sol transition of the hydrogel. The presence of salts, such as NaCl, can further modulate the hydrogen-bonding network by influencing the hydration shell and ionic strength, which not only affects the ionic conductivity but also the gelation kinetics and thermal responsiveness.

[0212] After mixing, both nucleated and bicontinuous ionic biogel system forms an amorphous state due to kinetic constraints of the biogel phase at room temperature; upon heating, the mixing enthalpy (AHm(X) reduces due to the reduction in Flory-Huggins parameter, leading to partial miscibility for the bicontinuous system and complete miscibility for the nucleated system. Upon cooling, the Flory -Huggins parameter increases, favouring phase separation and immiscibility. However, changing the mixing sequence, phase separation occurs in two distinct ways: 1) liquid - liquid phase separation (LLPS) in nucleated systems with isolated PEDOT domains and 2) viscoelastic phase separation (VPS) in bicontinuous systems. But all the thermodynamic potential such as Gibbs’ free energy and thermodynamic quantities such asAtty. Ref. No. 0073605-001078Flory -Huggins’s parameter are path-independent and only state-function, therefore, the change of phase morphology and thermodynamics due to the mixing-sequence can only result from some non - equilibrium dissipative phenomenon such as the difference in kinetics of the two ionic biogel system - nucleated (high phase mobility Mg, of ionic phase before mixing) and bicontinuous (low phase mobility Mg, of ionic phase during mixing as biogel phase remains kinetically constrained). For the nucleated system, high phase mobility Mg, of the ionic phase brings the system into thermal equilibrium as the entropy is maximized to create distinct individual ionic phases, promoting complete phase separation, typically observed in MLOs, where compartmentalization arises from weak, dynamic interactions. With the increase in the polymeric concentration in the nucleated system, the PEDOT phases tend to get more populated yet remain nucleated (FIG. 5). In comparison, for bicontinuous systems, low phase mobility Mg, of the amorphous biogel phase restricts the complete mixing of the ionic phase and creates a percolated PEDOT phase with large phase boundaries, which increases the total interfacial enthalpy along with mixing enthalpy and reduces entropy compared to nucleated systems, therefore promoting enthalpy-driven thermodynamics over entropy-driven. This creates a non-monotonous Gibb’s free energy landscape (FIG. 1) with polymeric concentration-dependent phase morphology.

[0213] Viscoelastic Phase Separation (VPS) and Liquid - Liquid Phase Separation (LLPS) in Ionic Biogels Inspired by Membraneless Organelles

[0214] In LLPS, multivalent proteins and RNAs demix into droplets that behave as dynamic liquids: they round up, fuse rapidly, exchange components with the surroundings, and remodel composition in response to signalling. This fluidity underpins functions that requireAtty. Ref. No. 0073605-001078rapid turnover and selective concentration — such as RNA processing in stress granules and nucleolar ribosome biogenesis — where weak, reversible interactions create a dense phase without long-lived mechanical memory. In vitro reconstitutions and in vivo imaging established LLPS as a general organizational principle for membraneless compartments in which capillarity and diffusion dominate the mesoscale dynamics.

[0215] Yet when biological function demands organizing chromosomes, buffering forces, or templating reactions - the crowded, crosslinked milieu drives condensates into regimes where viscoelasticity constrains their evolution. In VPS, one component or the surrounding milieu relaxes far more slowly than its partner, so demixing is coupled to the buildup and release of internal stress. The result is qualitatively different morphologies and kinetics: strands and spacespanning networks form, coarsening is delayed or partially arrested, and shape anisotropy persists. Tanaka’s framework rationalizes these outcomes in terms of dynamic asymmetry between slow, network-forming macromolecules (for example, long RNAs or low-complexity protein polymers) and their faster partners. Cells naturally realize this asymmetry through regulated multivalency, post-translational modification, and ATP-driven remodelling that tune the lifetime and connectivity of transient crosslinks. VPS thus provides a route to mechanically robust scaffolds and long-lived microenvironments, when retaining shape, resisting coalescence, or storing elastic energy is advantageous.

[0216] Coherence of Characteristics of Distinct Phases

[0217] From a statistical and thermodynamic standpoint, the presence of phase separation and metastability can be conceptualized through free-energy landscapes and energetic barriers that emerge when a mixed system spontaneously decomposes into two coexisting phases. Each separated phase represents a region — characterized by distinct molecular densities, interactionAtty. Ref. No. 0073605-001078strengths, or order parameters — where the system can locally minimize its free energy. In each phase, the collective excitations, such as electrons, holes, or phonons, adopt specific local equilibrium distributions and dispersion relations that are consistent across their phase boundaries. Metastable interfaces then form natural energy barriers, restricting certain excitations from freely crossing between phases. At the interface between these domains, there is an energy cost associated with gradients, governed by a surface tension term. This surface tension imposes a potential barrier that excitations must overcome to transform from one phase to another.

[0218] By treating electrons, holes, or phonons as quasiparticles with given energy distributions in Kramer’s escape model, their probability of occupying states in a given region is controlled by Boltzmann or Fermi-Dirac statistics. Within one phase, the density of states, effective masses, or vibrational spectra differ from those in the other phase due to variations in underlying molecular arrangements. The interface thus acts as an energy barrier to cross from one domain into the other, so a quasiparticle must have sufficient energy to overcome differences in chemical potential, band alignment, or phonon dispersion relations. Mathematically, if the energy difference or barrier at the interface isthe probability of a quasiparticle in phase A entering phase B is suppressed by a Boltzmann factor e-ΔE / kTor a related statistical weight. Hence, low-energy excitations may remain confined to their original phase, ensuring that each domain preserves its characteristic properties. The result is that charge carriers (electrons, holes) that might dominate transport or scattering in one phase do not simply diffuse into the other and dilute or disrupt its properties.

[0219] Thermodynamics Governing Phase-Separation in Both Ionic Biogel SystemsAtty. Ref. No. 0073605-001078

[0220] Phase-separation between ionic and biogel phases occurs in both nucleated and bicontinuous systems. But the difference in the kinetics of mixing changes the phase morphology. In nucleated systems, phase separation occurs in the pre-gelation time, then it gets kinetically arrested during gelation, resulting in an isolated PEDOT phase embedded in the biogel matrix. For the bicontinuous system, phase separation occurs in the gelation phase (when PEDOT: PSS is mixed) due to immiscibility. The high activation energy barriers and limited phase mobility of biogel at room temperature trap the system in an amorphous state initially at room temperature. As the temperature increases, the Flory-Huggins interaction parameter decreases (as explained in the following), leading to a negative or near-zero Afmixand making the system thermodynamically favourable for mixing. As a result, the polymers become partially miscible, forming a homogeneous mixture. Cooling back to room temperature — from high temperature for the first time and onwards — results in ionic biogel with a stable phase-separated state (for nucleated) or metastable or unstable configuration with percolated PEDOT phases (for bicontinuous) rather than the initial amorphous gel.

[0221] The change in the total Gibbs free energy upon mixing (Afmix) of the two networks can be expressed as:ΔGmix= ΔHmix− TΔSmix, (8)

[0222] where AHmixis the enthalpy change of mixing, d Smixis the entropy change of mixing, and T is the absolute temperature. For the initial polymer blends at room temperature, the enthalpy of mixing is influenced by the interaction parameter according to the Flory-Huggins theory, which quantifies the energetic interactions between the polymers:ΔHmix= RTχφAφB, (9)Atty. Ref. No. 0073605-001078

[0223] where R is the gas constant, <pAand (pBare the volume fractions of networks A and B, respectively. The interaction parameter can be related to the interaction energies between like and unlike components:X = (10)

[0224] where z is the coordination number, k is the Boltzmann constant, and eABis the interaction energy between components A and B. Alternatively, the Flory -Huggins interaction parameter can be expressed as a function of the solubility parameters (5^ and 8Bof Networks A and B), with Vref being a reference molar volume:χ = (Vref / RT)(δA- δB)². (11)

[0225] In both systems during pre-gelation, the significant differences in bonding schemes — electrostatic interactions in the PEDOT: PSS / ionic liquid network (network A) and hydrogen bonding in the gelatin / glycerol / salt network (network B) — result in a large positive x at room temperature, leading to phase separation - isolated for nucleation and percolated for bicontinuous.

[0226] The interaction between the PEDOT: PSS / ionic liquid network and the gelatin / glycerol / salt network is weak due to the fundamental incompatibility of their bonding mechanisms:I. Lack of Favourable Interactions: The electrostatic network lacks the functional groups necessary to engage in hydrogen bonding with the gelatin network. Similarly, hydrogenbonding groups from the gelatin network do not effectively interact with the charged species in the electrostatic network.Atty. Ref. No. 0073605-0010782. Energetic Disparity: The intra-network interactions (eAAfor the electrostatic network and eBBfor the hydrogen-bonding network) are strong and energetically favourable. Therefore, eAAand eBBare large negative values. On the other side, the inter-network interactions (eAB) are weaker because there is no efficient mechanism for the networks to stabilize each other through bonding, making eABa small negative number21. Therefore, the intra- and inter-network interactions are related as:(cAB- -£^^) » kT. (12)Substituting these values in Equation S10 shows that % is large and positive: % » 1. This large positive % reflects the significant energetic penalty for mixing the two networks, due to the unfavourable interactions between their dissimilar bonding schemes at room temperature.3. Differences in Solubility Parameters: Due to the different types of interactions (electrostatic vs. hydrogen bonding), Networks A and B have significantly different solubility parameters. The square of their difference is large:(^ - 5B)2» 0. (13)This leads to a large positive, indicating immiscibility due to unfavourable energetic interactions.

[0227] Mixing the two networks would disrupt the favourable intra-network interactions without providing equally favourable inter-network interactions. The entropy of mixing (ASmix)Atty. Ref. No. 0073605-001078for polymers is generally small due to their high molecular weights, which limits the configurational entropy gain upon mixing. The entropy of mixing is given by:ASmix= -k (^ln^ + ^ln0B), (14)

[0228] where NAand NBare the degrees of polymerization of networks A and B. Large NAand NBgive small ASmix, making the entropic contribution Afmixinsufficient to overcome the unfavourable enthalpic contribution.

[0229] Consequently, the total Gibbs free energy change upon mixing becomes positive for both systems at room temperature:Afmix= (15)

[0230] The incompatibility between the electrostatic interactions in Network A and the hydrogen bonding in Network B leads to thermodynamically unfavourable mixing, characterized by a positive Gibbs free energy of mixing. This positive Gibbs free energy and slow kinetics indicate that the system minimizes its free energy by remaining amorphous at room temperature. However, upon increasing the temperature, the system becomes partially miscible because the Flory -Huggins interaction parameter % decreases with temperature. A lower value reduces the enthalpic penalty associated with the mixing of the two networks, leading to a smaller (positive) Gibbs free energy of mixing. This temperature-induced decrease in % facilitates mixing between the networks, making the system thermodynamically favourable for partial miscibility.

[0231] The interaction parameter is known to be temperature-dependent and can be expressed as:Atty. Ref. No. 0073605-001078(16)

[0232] where A and B are empirical constants to reflect the enthalpic and entropic contributions, respectively. As temperature increases, the - term decreases, leading to a reduction in / . This reduction can reach a critical point, where x becomes sufficiently small or even negative, favouring miscibility. Higher temperatures provide sufficient thermal energy to overcome kinetic barriers such as chain entanglement and viscosity. Enhanced diffusion allows the polymers to mix more thoroughly, leading to a homogeneous partially miscible state.

[0233] However, cooling back to room temperature increases / and leads to a positive enthalpy of mixing; therefore, the Gibbs free energy of mixing becomes positive, resulting in phase- separation. During heating, the polymers rearranged into a more thermodynamically favourable configuration, overcoming initial kinetic barriers. The cooling process follows a different path on the Gibbs free energy landscape compared to initial mixing. The initial amorphous state results from kinetic trapping during mixing. Upon cooling (from high temperature), the system has already surpassed these kinetic barriers and cannot revert to the original amorphous configuration. The thermoreversible behaviour of the gelatin network facilitates reversible transitions between miscible and partially miscible states. Upon heating, the hydrogen bonds within the gelatin network are disrupted. Heating provides sufficient thermal energy to overcome the energy of hydrogen bonds, causing them to break, which increases the enthalpy associated with hydrogen bonding and enhances chain mobility. The increase in chain mobility further leads to a rise in entropy due to a greater number of accessible conformations.

[0234] Di fference in Kinetics leading to VPS and LLPSAtty. Ref. No. 0073605-001078

[0235] Though both systems have phase separation akin to their positive mixing free energy, the difference in the phase morphology occurs due to non-dissipative forces like kinetics and interfacial forces. Though mixing free energy indicates the phase separation but other free energy needs to be considered. The total Gibbs free energy F for a nucleated system (LLPS -based) is given as:F f felastic t*) + fmix^ dV, (17) Where,fmixW) = 7? T (^ln^ +^ln0B+Z^0B) (18)andfelastlcW = ~G^ ~ I): (W — I) + Gbiogel. (19)

[0236] In the above equation, G is the shear modulus of the polymeric network given by G~Gopp and I is the identity matrix, Gbiogeiis the elastic free energy due to the gelatin-based matrix, and W is the conformation matrix due to the polymeric matrix given by1 IV- 'ni> 1 Rf1 W = - > (20)?lp 3d NeJ

[0237] where npis the number of polymeric chains and ’th polymer chain has Ztnumber of entangled segments with position vectors Rndirected from rfnto rfn+1. At equilibrium, the average length ofis where Neis the average number of segments existing between the two adjacent entangled segments along a chain. However, for a nucleated system, np= 0 as it lacks polymeric networks, making W — I = 0.In comparison, for bicontinuous (VPS - based)F = f ^ l ^l2+ fmiXW + felastic(( / >) dV, (21)Atty. Ref. No. 0073605-001078

[0238] where K is the interfacial parameter. In this case, W — I 0, and there is a tradeoff between polymeric elastic free energy and Gbiogei, with high concentration of PEDOT: PSSresulting in - (W — I): (W — I) » Gbiogei. The liquid-like rheology for the bicontinuous systemw.r.t. to gelatin-based matrix can be given as(£(JV- / ):(JV-Z) Img\ - +: tan 5 Bicontinuous > (, biogel (22) tan 8Biogei( ^biogelThe chemical potential / z is given as=_ ndf M = (238<p dtp d(V<py )where F is related to the total Gibbs free energy and the total stress:a = 2W • — + Gbiogel= 2 GW ■ (W — I) + Gbiogel. (24)The dynamics of these phases are given by the Cahn-Hillard equation:

[0239] where M(pis the mobility and considering that the mean velocity is zero. The spinodal line is given by the polymeric composition when 7 / z = 0 and the spinodal decomposition or unstable thermodynamic state occurs when 7 / z < 0. For LLPS, 7 • a = 0, and only mixing energy or osmotic stress are critical, whereas for VPS, stress forces like friction between the polymer and the biogel matrix play a critical role in phase morphology.Atty. Ref. No. 0073605-001078

[0240] The molecular interactions between the biogel phase and the ionic phase for both nucleated and bicontinuous systems can be elucidated from a comprehensive series of characterizations.

[0241] Material Characterization of Ionic Biogel

[0242] X-ray photoelectron spectroscopy

[0243] X-ray photoelectron spectroscopy (XPS) analysis of the ionic biogel (nucleated 35 w / w%) reveals the presence of key carbon, nitrogen, and sulphur species, including CHX(25.6%), C-(O, N) (27.4%), and SO3 (6.2%). The detection of sulfonate (SO3) groups and thiols confirms the functionality of PEDOT: PSS, while fluorocarbon and siloxane signals suggest interactions with the ionic liquid EMIM-TFSI. Additionally, the presence of protonated amines (N-C~, 2.9%) and carbonyl groups (C=O, 5.1%) underscores the role of the gelatin-glycerol matrix in stabilizing the ionic and electronic interfaces.

[0244] Raman spectroscopy

[0245] Raman spectroscopy at different temperatures was carried out for the ionic biogel with nucleated 35 w / w% and bicontinuous 100 w / w% systems. For the nucleated system, the Raman spectra reveal that the Ca=Cp symmetric stretching vibration peaks of PEDOT exhibit a red shift from 1423 cm1at 25°C and 30°C to 1417 cm1at 40°C and 50°C, with an accompanying increase in intensity up to 40°C, followed by a decrease at 50°C post-phase transition. This shift indicates that a higher proportion of benzoid moieties in PEDOT is converted to the quinoid structure due to oxidative charge transfer doping at elevated temperatures, resulting in a more planar polymer backbone. Concurrently, the Amide I band associated with the C=O stretching vibrations in gelatin increases in intensity from 25°C to 40°C and then diminishes at 50°C, suggesting the formation and subsequent disruption ofAtty. Ref. No. 0073605-001078intermolecular hydrogen bonding interactions between gelatin and glycerol molecules. These findings indicate that elevated temperatures promote both the unwrapping of gelatin's helical structure and the planarization of PEDOT chains, leading to synergistic enhancements in the electrical and mechanical properties of the ionic biogel.

[0246] Fourier-transform infrared spectroscopy

[0247] The Fourier-transform infrared spectroscopy (FTIR) spectra reveal strong characteristic infrared absorption peaks of thiophene functional groups at 1,640 cm with a markedly higher absorption intensity observed during heating for nucleated 35 w / w%, 100 w / w% and bicontinuous 100 w / w%, 200 w / w%. This increase in absorption intensity at elevated temperatures suggests enhanced vibrational activity of the thiophene rings within the PEDOT chains, potentially due to increased conjugation length arising from thermal effects. Such changes may facilitate greater 7i-electron delocalization and contribute to the improved charge mobility or conductivity of the ionic biogel at higher temperatures. The Amide A band — corresponding to the N-H and O-H stretching vibrations — exhibits a blue shift from 3,287 cm1at 25°C to 3,317 cm1at 45°C, along with notable peak broadening. This shift to higher wavenumbers indicates a decrease in hydrogen bonding interactions within the gelatin-glycerol-salt hydrogel matrix as temperature increases. The disruption of hydrogen bonds by thermal agitation strengthens the N-H bonds, causing them to absorb at higher frequencies (blue shift). The observed peak broadening suggests increased molecular disorder and a wider distribution of hydrogen-bonding environments resulting from the enhanced thermal motion of gelatin chains.

[0248] Atomic force microscopy

[0249] The atomic force microscopy (AFM) images reveal a hierarchical porous architecture featuring interconnected pores that range from nanometres to micrometres in size forAtty. Ref. No. 0073605-001078both nucleated (35 w / w%) (FIG. 46) and bicontinuous (100 w / w%) (FIG. 47) systems. This hierarchical porosity arises from the thermodynamically driven phase separation between the hydrophilic gelatin-glycerol network and the more hydrophobic PEDOT: PSS / EMIM-TFSI domains during the gelation process.

[0250] Micro-computed tomography

[0251] The phase-separation can also be observed in micro-computed tomography for both nucleated (100 w / w%) (FIG. 48) and bicontinuous (100 w / w%) (FIG. 49) due to the difference in optical density of the ionic phase and gelatin-based biogel phase.

[0252] Room-temperature UV-Vis

[0253] The UV-Vis-NIR spectra exhibit a significant redshift, with the characteristic absorption peak of PEDOT appearing around -950 nm (bicontinuous 100 w / w%) instead of the typical -800 nm observed in pristine PEDOT films, whereas in nucleated 35 w / w%, there is no obvious peak (FIG. 50). This pronounced shift to longer wavelengths indicates an increase in the effective conjugation length and enhanced delocalization of ^-electrons along the PEDOT backbone within the ionic biogel matrix.

[0254] Grazing-incidence wide-angle X-ray scattering

[0255] The grazing-incidence wide-angle X-ray scattering (GIWAXS) patterns reveal notable temperature-dependent changes in the crystalline ordering of the PEDOT: PSS domains within the biogel matrix for nucleated (35 w / w%) (FIGS. 51 and 52) and bicontinuous (100 w / w%) (FIG. 53) systems. Specifically, for nucleated 35 w / w%, the (200) d-spacing, corresponding to the scattering vector qz-0.4 A ', exhibits an increase from 0.011 (a.u.) to 0.014 (a.u.) as the temperature is elevated from 25°C to 40°C, whereas no obvious change is observed for the bicontinuous system. The peak at qz~0.87 A1in GIWAXS patterns for the bicontinuousAtty. Ref. No. 0073605-001078system, previously assigned to the stacking of PEDOT chains along the 7t-7t direction, remains consistent in intensity and position at 25°C to 60°C, indicating stable it- 71 stacking interactions within the PEDOT domains across this temperature range. The unchanged ordering suggests that the planarization and increased conjugation of the PEDOT chains at elevated temperatures up to 60°C do not disrupt the overall stacking arrangement but may enhance charge transport by improving orbital overlap.

[0256] Biocompatibility

[0257] Despite the known cytotoxicity of EMIM-TFSI, the inherent biocompatibility of the gelatin-glycerol matrix effectively encapsulates and screens the PEDOT: PSS / EMIM-TFSI components, ensuring that the composite can be safely integrated with the scalp or skin. The gelatin-glycerol hydrogel acts as a biocompatible barrier, preventing direct contact between the ionic liquid and biological tissues while maintaining the composite's functional properties.Applying the nucleated 35 w / w% ionic biogel to the forearm skin of human subjects for one week evaluates the biocompatibility. Throughout the application period, no signs of skin irritation, inflammation, or adverse reactions are observed (FIG. 54). The biocompatibility of the ionic biogel is also confirmed with the MTT assay (FIG. 55). The cell viability of 89% and 110% in 24 h and 48 h is comparable to that of 100% and 127% from the control, supporting the proliferative effects of hydrogels on MCF-10A cells (FIG. 56). The demonstrated biocompatibility is critical to prevent adverse immune responses and ensure the longevity of the device.Supplementary Note 2

[0258] Thermoreversible gels as the neural interface must pass through the rheological crossover tan 5 = 1 close to 37°C, so they can be printed or extruded in the sol state and rapidlyAtty. Ref. No. 0073605-001078recover an adhesive gel once in contact with the scalp. This crossover temperature, Tgei, can be controlled by balancing the enthalpic strength and kinetic lifetime of hydrogen bonds that knit the matrix, against the geometric confinement imposed by the characteristic size f of the PEDOT: PSS domains that may isolate (nucleated system) or percolate (bicontinuous) to provide electronic conduction.

[0259] At the gel point Tgei, the storage and loss moduli become equal, giving tan 8 =— = 1 at a representative frequency c (e.g., 1 Hz).

[0260] The relaxation time r(T) follows the Arrhenius relation:T T) = TQe-^, (26)

[0261] where Eais the activation energy of the hydrogen bond breaking. Therefore, the gel crossover point Tgeiyields:~ JTATZ (27)r(Tgel)

[0262] Where, T0is the reference time constant and T(Tgei) is a fixed time constant for a particular frequency. Optimizing Tgeirequires controlling the activation energy for hydrogen bond breaking at a constant probing frequency.

[0263] Gelatin matrices gel via cooperative hydrogen bonds (AHh ~ 5-20 kJ mol1), so that Ea~ NhHhscales with hydrogen bond junction density Nh. Introduction of H-bond disruptors (e.g., glycerol and ionic liquids) lowers Eaand depresses Tgehwhereas increasing gelatin or water content (from PEDOT: PSS) raises Eaand hence Tgei. Moreover, using hydrophobic DES increases the hydrogen bond donor for increased hydrogen bond junctionAtty. Ref. No. 0073605-001078density, which increases Eaand hence Tgeito result in gel phase only. In comparison, hydrophilic DES and EMIM-OTF are soluble in PEDOT: PSS to hinder the hydrogen bonding from water, resulting in lowered Eaand decreased Tgei.

[0264] Moreover, for bicontinuous systems, percolated PEDOT: PSS domains with equivalent diameter f impose large geometric drag on network dynamics, with the characteristic geometric relaxation time scaling as:(28)

[0265] Where, D(7^ei) is the diffusion constant of the matrix at temperature Tgei.Experimentally, increasing PEDOT: PSS / IL concentration first raises Tgeidue to mild dehydration and interfacial crosslinking (increased Ea), but at higher loadings, network plasticization and fragmentation collapse Nh to lower Eaand decrease Tgei.Combining both effects gives:Ea(29)\aD(Tgel)

[0266] where a is a proportional constant. To achieve tan 5 = 1 near 35-38 °C while maintaining conductivity, PEDOT: PSS / IL content is optimized to be just below percolation (for the bicontinuous system), where Ea(-120-140 kJ mol1) is tuned via ionic liquid or PEDOT: PSS concentration. In nucleated systems, Ea» akBTref In d / d0, so Tgeiis influenced by both the concentration of PEDOT: PSS and the type of ionic liquids. In comparison, for bicontinuousAtty. Ref. No. 0073605-001078systems, Ea« akBTref In d / d0for the percolated long PEDOT: PSS domains (where the spinodal decomposition sets in), the concentration of PEDOT: PSS becomes more dominant.

[0267] It should be understood that modifications to the embodiments disclosed herein can be made to meet a particular set of design criteria. For instance, the number of or configuration of components or parameters may be used to meet a particular objective.

[0268] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternative embodiments may include some or all of the features of the various embodiments disclosed herein. For instance, it is contemplated that a particular feature described, either individually or as part of an embodiment, can be combined with other individually described features, or parts of other embodiments. The elements and acts of the various embodiments described herein can therefore be combined to provide further embodiments.

[0269] It is the intent to cover all such modifications and alternative embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof.Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points. Thus, while certain exemplary embodiments of the apparatus and process and / or utilization and methods of making and using the same have been discussed and illustrated herein, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

1. Atty. Ref. No. 0073605-0010782.What is claimed is:

1. A method of making a nucleated ionic biogel, the method comprising:4.combining conductive or semiconductive polymers, one or more ionic liquids, and one or more salts to form a first solution; and5.adding matrix-forming polymers and one or more plasticizers to the first solution to form the nucleated ionic biogel.

2. The method of claim 1, wherein a concentration of the conductive or semiconductive polymers is greater than 0 w / w% and less than or equal to 200 w / w% relative to a concentration of the matrix-forming polymers.

3. The method of claim 1, wherein a concentration of the conductive or semiconductive polymers is greater than or equal to 100 w / w% and less than or equal to 125 w / w% relative to a concentration of the matrix-forming polymers.

4. The method of claim 1, wherein the conductive or semiconductive polymers are selected from the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly [3,3 '-bis[2-[2-(2 -methoxy ethoxy )ethoxy]ethoxy]-2,2':5',2''-terthiophene-5, 5"-diyl] (pg2T-T).Atty. Ref. No. 0073605-0010785. The method of claim 4, wherein the conductive or semiconductive polymers are PEDOT: PSS.

6. The method of claim 1, wherein the ionic liquids are selected from the group consisting of 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf), and deep eutectic solvents (DES).

7. The method of claim 1, wherein the salts are selected from the group consisting of sodium chloride, potassium chloride, and lithium chloride.

8. The method of claim 1, wherein the matrix-forming polymers are selected from the group consisting of gelatin, agar, and cellulose.

9. The method of claim 1, wherein the plasticizers are selected from the group consisting of glycerol and dimethyl sulfoxide.

10. A nucleated ionic biogel formed from the method of claim 1.

11. A method of making a nucleated ionic biogel, the method comprising:16.combining poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), one or more ionic liquids, and one or more salts to form a first solution; and17.adding gelatin and glycerol to the first solution to form the nucleated ionic biogel. Atty. Ref. No. 0073605-00107812. The method of claim 11, wherein a concentration of the PEDOT: PSS is greater than or equal to 100 w / w% and less than or equal to 125 w / w% relative to a concentration of the matrixforming polymers.

13. A nucleated ionic biogel formed from the method of claim 11.

14. A method of making a bicontinuous ionic biogel, the method comprising:21.combining matrix-forming polymers and one or more plasticizers to form a first solution; and22.adding one or more salts and one or more ionic liquids to the first solution to form a second solution; and23.adding conductive or semiconductive polymers to the second solution to form the bicontinuous ionic biogel.

15. The method of claim 14, wherein a concentration of the conductive or semiconductive polymers is greater than 0 w / w% and less than or equal to 200 w / w% relative to a concentration of the matrix-forming polymers.

16. The method of claim 14, wherein the conductive or semiconductive polymers are selected from the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly [3,3 '-bis[2-[2-(2 -methoxyethoxy )ethoxy]ethoxy]-2,2':5',2"-terthiophene-5, 5"-diyl] (pg2T-T).Atty. Ref. No. 0073605-00107817. The method of claim 16, wherein the conductive or semiconductive polymers are PEDOT: PSS18. The method of claim 14, wherein the ionic liquids are selected from the group consisting of 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM-OTf), and deep eutectic solvents (DES).

19. The method of claim 14, wherein the salts are selected from the group consisting of sodium chloride, potassium chloride, and lithium chloride.

20. The method of claim 14, wherein the matrix-forming polymers are selected from the group consisting of gelatin, agar, and cellulose.

21. The method of claim 14, wherein the plasticizers are selected from the group consisting of glycerol and dimethyl sulfoxide.

22. A bicontinuous ionic biogel formed from the method of claim 14.

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