Direct Laser Processing and Functionalizing PI/PDMS Composites for an On-Demand, Programmable, Recyclable Device Platform.

Skin-interfaced high-sensitive biosensing systems to detect electrophysiological and biochemical signals have shown great potential in personal health monitoring and disease management. However, the integration of 3D porous nanostructures for improved sensitivity and various functional composites for signal transduction/processing/transmission often relies on different materials and complex fabrication processes, leading to weak interfaces prone to failure upon fatigue or mechanical deformations. The integrated system also needs additional adhesive to strongly conform to the human skin, which can also cause irritation, alignment issues, and motion artifacts. This work introduces a skin-attachable, reprogrammable, multifunctional, adhesive device patch fabricated by simple and low-cost laser scribing of an adhesive composite with polyimide powders and amine-based ethoxylated polyethylenimine dispersed in the silicone elastomer. The obtained laser-induced graphene in the adhesive composite can be further selectively functionalized with conductive nanomaterials or enzymes for enhanced electrical conductivity or selective sensing of various sweat biomarkers. The possible combination of the sensors for real-time biofluid analysis and electrophysiological signal monitoring with RF energy harvesting and communication promises a standalone stretchable adhesive device platform based on the same material system and fabrication process.

Mechanically Excellent, Notch-Insensitive, and Highly Conductive Double-Network Hydrogel for Flexible Strain Sensor.

A novel double-network conductive hydrogel based on lithium acetate/gelatin/polyacrylamide (PAAM) was synthesized by heating-cooling and subsequent γ-ray radiation-induced polymerization and cross-linking. Owing to the hydrogen bonding interaction between lithium acetate, physical cross-linked gelatin, and chemical cross-linked PAAM, the resultant hydrogel exhibited high tensile strength (1260 kPa), high ionic conductivity (35.2 mS cm-1), notch-insensitivity (tensile strength 415 kPa, elongation at break 872% with transverse notch), and extensive strain monitoring range (0.15-800%) under optimum conditions. The lithium acetate/gelatin/polyacrylamide hydrogel strain sensor attached to the skin can sensitively monitor the subtle movements of the human body. The strain sensor based on the resultant hydrogel with transverse notch can still work for 1200 cycles, due to that the covalent-cross-linked PAAm chain bridges the cracks and stabilizes the deformation, while the physical-cross-linked gelatin was unzipped to make the blunting of notch. The conductive hydrogel with high-sensitivity and high stability is expected to be used as materials for the preparation of flexible strain sensors in the future.

Mechanically Robust and Highly Conductive Poly(ionic liquid)/Polyacrylamide Double-Network Hydrogel Electrolytes for Flexible Symmetric Supercapacitors with a Wide Operating Voltage Range.

Flexible electronic devices, such as supercapacitors (SCs), place high demands on the mechanical properties, ionic conductivity, and electrochemical stability of electrolytes. Hydrogels, which combine flexibility and the advantages of both solid and liquid electrolytes, will meet the demand. Here, we report the synthesis of novel poly(ionic liquid)/polyacrylamide double-network (DN) (PIL/PAM DN) hydrogel electrolytes containing different metal salts via a two-step γ-radiation method. The resultant Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte possesses excellent mechanical properties (tensile strength of 3.64 MPa, elongation at break of 446%) and high ionic conductivity (24.1 mS·cm-1). The corresponding flexible SC based on the Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte (SC-Li2SO4) presents improved ion diffusion, ideal electrochemical double-layer capacitor behavior, good rate capability, and excellent cyclic stability. Moreover, symmetric SC-Li2SO4 achieves a wide operating voltage range of up to 1.5 V, with a maximum energy density of 26.0 W h·kg-1 and a capacitance retention of 94.1% after 10,000 galvanostatic charge-discharge cycles, owing to the deactivation of free water molecules by the synergistic effect of PIL, PAM, and SO42-. Above all, the capacitance of SC-Li2SO4 is well-maintained after overcharge, overdischarge, short circuit, extreme temperature, compression, and bending tests, indicating its high security and flexibility. This work reveals the enormous application potential of PIL-based conductive hydrogel electrolytes for flexible electronic devices.

Stretchable, Flexible, Breathable, Self-Adhesive Epidermal Hand sEMG Sensor System.

Hand function rehabilitation training typically requires monitoring the activation status of muscles directly related to hand function. However, due to factors such as the small surface area for hand-back electrode placement and significant skin deformation, the continuous real-time monitoring of high-quality surface electromyographic (sEMG) signals on the hand-back skin still poses significant challenges. We report a stretchable, flexible, breathable, and self-adhesive epidermal sEMG sensor system. The optimized serpentine structure exhibits a sufficient stretchability and filling ratio, enabling the high-quality monitoring of signals. The carving design minimizes the distribution of connecting wires, providing more space for electrode reservation. The low-cost fabrication design, combined with the cauterization design, facilitates large-scale production. Integrated with customized wireless data acquisition hardware, it demonstrates the real-time multi-channel sEMG monitoring capability for muscle activation during hand function rehabilitation actions. The sensor provides a new tool for monitoring hand function rehabilitation treatments, assessing rehabilitation outcomes, and researching areas such as prosthetic control.

Gamma Radiation Synthesis of Ag/P25 Nanocomposites for Efficient Photocatalytic Degradation of Organic Contaminant.

Titanium dioxide (TiO2) has garnered significant attention among various photocatalysts, whereas its photocatalytic activity is limited by its wide bandgap and inefficient charge separation, making the exploration of new strategies to improve its photocatalytic performance increasingly important. Here, we report the synthesis of Ag/P25 nanocomposites through a one-step gamma-ray radiation method using AgNO3 and commercial TiO2 (Degussa P25). The resulting products were characterized by powder X-ray diffraction, UV-Vis diffused reflectance spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The effect of free radical scavengers, feed ratios of Ag/P25, and dose rates on the photocatalytic activity of the Ag/P25 nanocomposites were systematically investigated using rhodamine B under Xenon light irradiation. The results showed that the Ag/P25 photocatalyst synthesized with a feed ratio of 2.5 wt% and isopropyl alcohol as the free radical scavenger at a dose rate of 130 Gy/min exhibited outstanding photocatalytic activity, with a reaction rate constant of 0.0674 min-1, much higher than that of P25. Additionally, we found that the particle size of Ag could be effectively controlled by changing the dose rate, and the Ag/P25 nanocomposites doped with smaller size of Ag nanoparticles performed higher photocatalytic activities. The synthesis strategy presented in this study offers new insight into the future development of highly efficient photocatalysts using radiation techniques.

Multifunctional Biosensing Platform Based on Nickel-Modified Laser-Induced Graphene.

Nickel plating electrolytes prepared by using a simple salt solution can achieve nickel plating on laser-induced graphene (LIG) electrodes, which greatly enhances the electrical conductivity, electrochemical properties, wear resistance, and corrosion resistance of LIG. This makes the LIG-Ni electrodes well suited for electrophysiological, strain, and electrochemical sensing applications. The investigation of the mechanical properties of the LIG-Ni sensor and the monitoring of pulse, respiration, and swallowing confirmed that the sensor can sense insignificant deformations to relatively large conformal strains of skin. Modulation of the nickel-plating process of LIG-Ni, followed by chemical modification, may allow for the introduction of glucose redox catalyst Ni2Fe(CN)6 with interestingly strong catalytic effects, which gives LIG-Ni impressive glucose-sensing properties. Additionally, the chemical modification of LIG-Ni for pH and Na+ monitoring also confirmed its strong electrochemical monitoring potential, which demonstrates application prospects in the development of multiple electrochemical sensors for sweat parameters. A more uniform LIG-Ni multi-physiological sensor preparation process provides a prerequisite for the construction of an integrated multi-physiological sensor system. The sensor was validated to have continuous monitoring performance, and its preparation process is expected to form a system for non-invasive physiological parameter signal monitoring, thus contributing to motion monitoring, disease prevention, and disease diagnosis.

MXene/Gelatin/Polyacrylamide Nanocomposite Double Network Hydrogel with Improved Mechanical and Photothermal Properties.

The development of smart hydrogel with excellent mechanical properties and photothermal conversion capability is helpful in expending its application fields. Herein, a MXene/gelatin/polyacrylamide (M/G/PAM) nanocomposite double network (NDN) hydrogel was synthesized by γ-ray radiation technology for the first time. Compared with gelatin/polyacrylamide double network hydrogel, the optimized resultant M3/G/PAM NDN hydrogel shows better mechanical properties (tensile strength of 634 ± 10 kPa, compressive strength of 3.44 ± 0.12 MPa at a compression ratio of 90%). The M3/G/PAM NDN hydrogel exhibits a faster heating rate of 30 °C min-1, stable photothermal ability, and mechanical properties even after 20 cycles of on-off 808 nm near-infrared (NIR) laser irradiation (1.0 W cm-2). Furthermore, the temperature of M3/G/PAM NDN hydrogel can be increased rapidly from 25 °C to 90 °C in 10 s and could reach 145 °C in 120 s under irradiation by focused NIR laser irradiation (56.6 W cm-2). The high mechanical property and photothermal properties of M/G/PAM hydrogel are ascribed to the formation of double network and uniform hydrogen bonding between MXene and gelatin and PAM polymers. This work paves the way for construction of photothermal hydrogels with excellent mechanical properties.

Study on Flexible sEMG Acquisition System and Its Application in Muscle Strength Evaluation and Hand Rehabilitation.

Wearable devices based on surface electromyography (sEMG) to detect muscle activity can be used to assess muscle strength with the development of hand rehabilitation applications. However, conventional acquisition devices are usually complicated to operate and poorly comfortable for more medical and scientific application scenarios. Here, we report a flexible sEMG acquisition system that combines a graphene-based flexible electrode with a signal acquisition flexible printed circuit (FPC) board. Our system utilizes a polydimethylsiloxane (PDMS) substrate combined with graphene transfer technology to develop a flexible sEMG sensor. The single-lead sEMG acquisition system was designed and the FPC board was fabricated considering the requirements of flexible bending and twisting. We demonstrate the above design approach and extend this flexible sEMG acquisition system to applications for assessing muscle strength and hand rehabilitation training using a long- and short-term memory network training model trained to predict muscle strength, with 98.81% accuracy in the test set. The device exhibited good flexion and comfort characteristics. In general, the ability to accurately and imperceptibly monitor surface electromyography (EMG) signals is critical for medical professionals and patients.

A Deep Neural Network Ensemble Classifier with Focal Loss for Automatic Arrhythmia Classification.

Automated electrocardiogram classification techniques play an important role in assisting physicians in diagnosing arrhythmia. Among these, the automatic classification of single-lead heartbeats has received wider attention due to the urgent need for portable ECG monitoring devices. Although many heartbeat classification studies performed well in intrapatient assessment, they do not perform as well in interpatient assessment. In particular, for supraventricular ectopic heartbeats (S), most models do not classify them well. To solve these challenges, this article provides an automated arrhythmia classification algorithm. There are three key components of the algorithm. First, a new heartbeat segmentation method is used, which improves the algorithm's capacity to classify S substantially. Second, to overcome the problems created by data imbalance, a combination of traditional sampling and focal loss is applied. Finally, using the interpatient evaluation paradigm, a deep convolutional neural network ensemble classifier is built to perform classification validation. The experimental results show that the overall accuracy of the method is 91.89%, the sensitivity is 85.37%, the positive productivity is 59.51%, and the specificity is 93.15%. In particular, for the supraventricular ectopic heartbeat(s), the method achieved a sensitivity of 80.23%, a positivity of 49.40%, and a specificity of 96.85%, exceeding most existing studies. Even without any manually extracted features or heartbeat preprocessing, the technique achieved high classification performance in the interpatient assessment paradigm.

Ultrastretchable and adhesive agarose/Ti3C2Tx-crosslinked-polyacrylamide double-network hydrogel for strain sensor.

A novel agarose/Ti3C2Tx-crosslinked-polyacrylamide (AG/T-PAM) double-network (DN) hydrogel is synthesized by combining heating-cooling and γ-ray radiation-induced polymerization. The AG/T-PAM DN hydrogel possesses excellent mechanical properties with 4250% stretchability, and good adhesion to different substrates, such as an adhesive strength of 1148 kPa to copper at 30 °C. The resultant hydrogel also exhibits excellent tensile and compression sensing properties due to the variation of conductive network within hydrogel. The flexible and wearable strain sensor composed of the AG/T-PAM DN hydrogel presents rapid response to strain withstand 1000 cycles, and can monitor various movements of human body with a high sensibility. The AG/T-PAM DN hydrogel-based strain sensor will have broad application in large-scale strain detection scenarios requiring high sensitivity and adhesion.

Polyacrylamide/Copper-Alginate Double Network Hydrogel Electrolyte with Excellent Mechanical Properties and Strain-Sensitivity.

The double network (DN) hydrogel has attracted great attention due to its wide applications in daily life. However, synthesis DN hydrogel with excellent mechanical properties is still a big challenge. Here, polyacrylamide/copper-alginate double network (PAM/Cu-alg DN) hydrogel electrolyte is successfully synthesized by radiation-induced polymerization and cross-linking process of acrylamide with N, N'-methylene-bis-acrylamide and subsequent cupric ion (Cu2+ ) crosslinking of alginate. The content of sodium alginate, absorbed dose, and the concentration of Cu2+ are investigated in detail for improving the overall properties of PAM/Cu-alg DN hydrogel electrolyte. The PAM/Cu-alg DN hydrogel electrolyte synthesizes by radiation technique and Cu2+ crosslinking shows superior mechanical properties with a tensile strength of 2.25 ± 0.02 MPa, excellent energy dissipation mechanism, and the high ionic conductivity of 4.08 ± 0.17 mS cm-1 . PAM/Cu-alg DN hydrogel is characterized with attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy analyses and the reason for the improvement of mechanical properties is illustrated. Furthermore, PAM/Cu-alg DN hydrogel electrolyte exhibits excellent strain-sensitivity, cyclic stability, and durability. This work paves for the new way for the preparation of DN hydrogel electrolytes with excellent properties.

Quaternary phosphonium modified cellulose microsphere adsorbent for 99Tc decontamination with ultra-high selectivity.

Decontamination of radioactive TcO4- from nuclear wastes is increasingly crucial for spent nuclear fuel reprocessing and environmental remediation. In the presence of a large excess of competitive anions, the selective separation of TcO4- is a major challenge for adsorbents. Herein, by using pre-radiation induced grafting polymerization, we have modified economical and environmentally friendly cellulose microspheres to obtain quaternary phosphonium decorated TcO4- adsorbents with an ultra-high selectivity, designated CMS-g-VBPPh3NO3. The prepared materials show adsorption capacities of 251 mg g-1 (for the surrogate Re). The selective factor against NO3- in 0.5 mol kg-1 HNO3 is as high as 168, showing excellent anion-exchange selectivity towards TcO4-. Moreover, CMS-g-VBPPh3NO3 was packed in column for treating simulated acidic waste solutions containing Cs, Sr, Eu, Zr, Ru, U and Re, and it showed excellent Re separation performance. Tracer amount of 99mTc experiments showed that comparing to ReO4-, CMS-g-VBPPh3NO3 has a better adsorption selectivity for TcO4-.

One-step radiation synthesis of agarose/polyacrylamide double-network hydrogel with extremely excellent mechanical properties.

A facile one-step radiation method is first developed to synthesize agarose/polyacrylamide (AG/PAM) double-network (DN) hydrogel. Compared to other synthetic methods of DN hydrogels, our synthesis method endows the resultant AG/PAM DN hydrogel with not only top-level tensile properties with a tensile strength of 1263 ± 59 kPa and an elongation at break of 3406 ± 143%, but also highest compression properties with a compression strength of 140 ± 3 MPa and a fracture compression strain of above 99.9%. An expanding-necking phenomenon during compression process of AG/PAM DN hydrogel were observed. We propose a chain pushing-in model to interpret the energy dissipation mechanism accounting for the super-compressibility of AG/PAM DN hydrogel. This novel radiation synthesis strategy provides an insight into the development of DN hydrogels with extremely excellent mechanical properties.

One-Pot Synthesis of a Double-Network Hydrogel Electrolyte with Extraordinarily Excellent Mechanical Properties for a Highly Compressible and Bendable Flexible Supercapacitor.

High-performance hydrogel electrolytes play a crucial role in flexible supercapacitors (SCs). However, the unsatisfactory mechanical properties of widely used polyvinyl alcohol-based electrolytes greatly limit their use in the flexible SCs. Here, a novel Li2SO4-containing agarose/polyacrylamide double-network (Li-AG/PAM DN) hydrogel electrolyte was synthesized by a heating-cooling and subsequent radiation-induced polymerization and cross-linking process. The Li-AG/PAM DN hydrogel electrolyte possesses extremely excellent mechanical properties with a compression strength of 150 MPa, a fracture compression strain of above 99.9%, a tensile strength of 1103 kPa, and an elongation at break of 2780%, greatly superior to those have been reported. It also achieves a high ionic conductivity of 41 mS cm-1 originating from its interconnected three-dimensional porous network structure that provides a three-dimensional channel for ionic migration. Compared to the SC applying Li2SO4 aqueous solution electrolyte, the corresponding flexible Li-AG/PAM DN hydrogel electrolyte-SC presents lower charge-transfer resistance, better ionic diffusion, being closer to ideal capacitive behaviors, superior rate capability, and better cycling stability, owing to the improved ionic transport in the Li-AG/PAM DN hydrogel electrolyte and electrode interfaces. Moreover, after testing with overcharge, short circuit, and high temperature, the capacitance of the Li-AG/PAM DN hydrogel electrolyte-SC can still be well maintained. Furthermore, the electrochemical properties of the Li-AG/PAM DN hydrogel electrolyte-SC remain almost intact under different compression strains/bending angles and even after 1000 compression/bending cycles. It is expected that the Li-AG/PAM DN hydrogel electrolyte may have broad applications in modern flexible and wearable electronics.

Oxidized multiwall carbon nanotube/silicone foam composites with effective electromagnetic interference shielding and high gamma radiation stability.

Oxidized multiwall carbon nanotubes (o-MWCNTs) were introduced into silicone foam to fabricate an electromagnetic interference (EMI) shielding material with high gamma radiation stability by solution casting followed by foaming and cross-linking reactions. The as-prepared o-MWCNT/silicone foam composites exhibited excellent mechanical strength and effective EMI shielding properties with superior EMI shielding effectiveness (SE) ranging from 26 to 73 dB at a 0.5-6.4 mm thickness with 30 wt% o-MWCNTs in the Ku band. Moreover, the composites have good gamma radiation stability, showing relatively stable EMI shielding properties and an improvement of hardness and pressure resistance after gamma irradiation with the absorbed dose of 500 kGy. These results indicate that the o-MWCNT/silicone foam composite is an attractive candidate for EMI shielding in some ionizing radiation environments.

Polymeric ionic liquid gels composed of hydrophilic and hydrophobic units for high adsorption selectivity of perrhenate.

The removal of TcO4 - from aqueous solutions has attracted more and more attention recently, and ReO4 - has been widely used as its natural analog. In this work, polymeric ionic liquid gel adsorbents, PC2-C12vimBr, with high adsorption capacity and selectivity towards ReO4 - were synthesized by radiation-induced polymerization and crosslinking. PC2-C12vimBr was composed of two monomers: a hydrophobic unit, 1-vinyl-3-dodecylimidazolium bromide for high selectivity, and a hydrophilic unit, 1-vinyl-3-ethylimidazolium bromide for improved kinetics. A gel fraction up to 90% could be achieved under 40 kGy with varied monomer ratios. The adsorption of PC2-C12vimBr gels for ReO4 - was evaluated by batch adsorption. The PC2-C12vimBr gel containing 20 mol% hydrophilic unit (named PC2-C12vimBr-A) could significantly improve the adsorption kinetics, which had an equilibrium time of ca. 24 h. The adsorption capacity obtained from the Langmuir model was 559 mg g-1 (Re/gel). The selective factor against NO3 - was 33.4 ± 1.9, which was more than 10 times higher than that of PC2vimBr, and it could maintain ReO4 - uptake as high as 100 mg g-1 in 0.5 mol kg-1 HNO3. The ΔHΘ and ΔSΘ of the NO3 -/ReO4 - ion-exchange reaction of PC2-C12vimNO3-A were -16.9 kJ mol-1 and 29 J mol-1 K-1, respectively, indicating physical adsorption. The adsorption mechanism of ReO4 - onto PC2-C12vimBr-A gel was ion-exchange, and it could be recovered using 5.4 mol kg-1 HNO3.

Tuning the Composition and Structure of Amorphous Molybdenum Sulfide/Carbon Black Nanocomposites by Radiation Technique for Highly Efficient Hydrogen Evolution.

Amorphous molybdenum sulfide/carbon black (MoSx/C) nanocomposites are synthesized by a facile one-step γ-ray radiation induced reduction process. Amorphous MoSx shows better intrinsic activity than crystalline MoS2. And the composition and amorphous structure of MoSx could be expediently tuned by absorbed dose for excellent catalytic activity. Meanwhile, the addition of carbon black leads to a significant decrease of charge transfer resistance and increase of active sites of MoSx/C composite. Consequently, MoSx/C nanocomposite shows Pt-like catalytic activity towards hydrogen evolution reaction (HER), which requires an onset over potential of 40 mV and over potential of 76 mV to achieve a current density of 10 mA cm-2, and the corresponding Tafel slope is 48 mV decade-1. After 6000 CV cycles, the catalytic activity of MoSx/C shows no obvious decrease. However, when platinum (Pt) foil is used as counter electrode, MoSx/C composite show better catalytic activity abnormally after long-term cycling tests. The dissolution of Pt was observed in HER and the Pt dissolution mechanism is elucidated by further analyzing the surface composition of after-cycling electrodes, which offers highly valuable guidelines for using Pt electrode in HER.

Radiation synthesis and performance of novel cellulose-based microsphere adsorbents for efficient removal of boron (III).

A novel cellulose-based microsphere containing glucamine groups, referred as CVN, was successfully synthesized by radiation-induced graft polymerization of 4-vinylbenzyl chloride onto cellulose microspheres and subsequent functionalization with N-methyl-d-glucamine. The adsorption by CVN for boron (III) from aqueous solutions was evaluated systematically by batch adsorption technique. Langmuir models could fit well with the adsorption behavior of CVN. The CVN adsorbents exhibited a high adsorption capacity up to 12.4mgg-1 towards boron (III) over the wide pH range of 5-8. After the addition of chloride salts, the boron uptake of CVN was enhanced that was attributed to the compensation of the surface charge generated by boron (III) adsorption leading to favor the adsorption. At high concentrations of salts, the ionic strength and different salts have no effect on the adsorption of boron(III). This work provides a new sustainable, cost effective material as a promising specific adsorbent for the removal of boron (III) from saline solutions.

Fast selective homogeneous extraction of UO22+ with carboxyl-functionalised task-specific ionic liquids.

The carboxyl-functionalised task-specific ionic liquid of 1-carboxymethyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide ([HOOCmim][NTf2]) was used as solvent and extractant for UO22+ extraction from aqueous solution. A homogeneous phase of [HOOCmim][NTf2]-H2O system could be achieved at 75 °C, and 86.8 ± 4.8% of UO22+ was separated from the aqueous solution after vibrating for only 1 min. Furthermore, nearly 97.3 ± 2.9% of UO22+ was stripped from [HOOCmim][NTf2] phase by 1 M HNO3 solution. K+, Na+, Mg2+, Dy3+, La3+, and Eu3+ have little influence on the homogeneous extraction of UO22+, and the extraction efficiency of UO22+ still remained at ca. 80%. Experimental and theoretical study on the selectivity of [HOOCmim][NTf2]-H2O system were performed for the first time. Density functional theory calculation indicates that the solvent effect plays a significant role on the selectivity of [HOOCmim][NTf2]-H2O.

Radiation Effect of Carboxyl-Functionalized Task-Specific Ionic Liquids on UO22+ Removal: Experimental Study with DFT Validation.

Experimental study with DFT validation on the effect of radiation on 1-carboxymethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([HOOCCH2MIM][NTf2]) as a solvent and extractant in rapid homogeneous extraction of UO22+ was performed for the first time. The radiolytic products of the anions and cations of [HOOCCH2MIM][NTf2] were identified by 19F NMR and high-resolution ESI-MS, respectively, and they were attributed to a decrease in UO22+ partitioning. Experimental study with DFT validation for complexing reactions between [HOOCCH2MIM][NTf2] and radiolytic products proved that F- competition was one of the main reasons for the decrease in UO22+ partitioning. However, UO22+ partitioning in irradiated [HOOCCH2MIM][NTf2] can largely be recovered after thorough water washing because of the removal of radiolytic products of [NTf2]-.