Theoretical Studies for the Structural Properties and Electron Transfer Reactivity of C₄H₅N/C₄H₅N⁺ Coupling System

The geometries and vibrational frequencies of pyrrole, pyrrole cation, and their corresponding encounter complexes have been determined using density functional theory (DFT) and/or ab initio methods with 6-31G* and/or 6-311+G* basis sets. Optimizations indicate that there are three stable complex modes. One mode has the ring−ring parallel contact (face−face) and each N atom in two rings is vertically over the center of another ring (complex 1). In the second mode (complex 2), two rings are also parallel, but they are directly contacted by only one N−C bond in each ring (side-side). The third mode (complex 3) is H−bond mode, in which the N−H of one pyrrole ring is nearly collinearly directed to the N center of another pyrrole ring and two rings are perpendicular to each other. For three-encounter complexes, their main bond lengths are between those of the pyrrole and those of the pyrrole cation. The character contact distances are 2.754 Å (C3···C13), 2.727 Å (C3···C12), and 2.632 Å (N1···H16) at the B3P86/6-31G* level, respectively. The stabilization energies of the three encounter complexes are calculated to be 21.4 (complex 1), 20.2 (complex 2), and 15.9 (complex 3) kcal/mol at the B3LYP-DFT/6-311+G* level with the correction for BSSE. The inapplicability of DFT methods has been discussed in predicting the energy curves, especially with long contact distance in which the DFT methods give the abnormal behavior for the dissociation of the complexes due to the “inverse symmetry breaking” problem. On the basis of three stable encounter complexes, three coupling modes have been designed by keeping the relative orientation and changing the contact distance for further investigating electron-transfer reactivity. The contact distance dependences of the activation energy, the coupling matrix element, and the electron-transfer rate have also been determined at the MP2/6-31G* level. Electron transfer can occur over a range of encounter distance. For the C4H5N/C4H5N+ coupling system, electron transfer occurs chiefly over a range of contact distances where 2.0Ra-b <6.0 Å. The most favorable coupling mode to electron transfer is the coupling mode 3, which is related to complex 3. It should be noted that it is not always true that the electron transfer must take place via the most stable encounter complex mechanism. For the C4H5N/C4H5N+ systems, the most stable encounter complex is complex 1, but the most favorable coupling mode for the electron transfer is coupling mode 3, depending on the different contact distance ranges

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Bioinspired Moisture-Driven Soft Actuators Based on MXene/Aramid Nanofiber Nanocomposite Films

Moisture-driven soft actuators are highly desirable in the fields of bionic robotics, artificial muscles, flexible electronics, etc. Here, a moisture-responsive actuator is fabricated by a mussel-inspired film structure composed of polydopamine-modified Ti3C2Tx MXene/aramid nanofiber (PDA-MXene/ANF) nanocomposites. The resultant actuator can be triggered by moisture and exhibits a large deformation (>360°) and high response speed (2 s) due to the remarkable hygroscopic performance of MXene. Moreover, the actuator exhibits a high tensile strength (374 MPa) and good toughness (12.3 MJ/m3). Several potential uses of the prepared nanocomposite film have been demonstrated, including biomimetic motion, electrical switches, crawling robots, and conceptual robotic arms. This bioinspired assembly strategy provides an approach for the development of high-performance moisture-driven soft actuators and expands the application of moisture actuator devices in soft robots by addressing the current shortcomings of the low strength and poor durability of MXene-based actuators

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics

Bioinspired Moisture-Driven Soft Actuators Based on MXene/Aramid Nanofiber Nanocomposite Films

Moisture-driven soft actuators are highly desirable in the fields of bionic robotics, artificial muscles, flexible electronics, etc. Here, a moisture-responsive actuator is fabricated by a mussel-inspired film structure composed of polydopamine-modified Ti3C2Tx MXene/aramid nanofiber (PDA-MXene/ANF) nanocomposites. The resultant actuator can be triggered by moisture and exhibits a large deformation (>360°) and high response speed (2 s) due to the remarkable hygroscopic performance of MXene. Moreover, the actuator exhibits a high tensile strength (374 MPa) and good toughness (12.3 MJ/m3). Several potential uses of the prepared nanocomposite film have been demonstrated, including biomimetic motion, electrical switches, crawling robots, and conceptual robotic arms. This bioinspired assembly strategy provides an approach for the development of high-performance moisture-driven soft actuators and expands the application of moisture actuator devices in soft robots by addressing the current shortcomings of the low strength and poor durability of MXene-based actuators

Bioinspired Moisture-Driven Soft Actuators Based on MXene/Aramid Nanofiber Nanocomposite Films

Moisture-driven soft actuators are highly desirable in the fields of bionic robotics, artificial muscles, flexible electronics, etc. Here, a moisture-responsive actuator is fabricated by a mussel-inspired film structure composed of polydopamine-modified Ti3C2Tx MXene/aramid nanofiber (PDA-MXene/ANF) nanocomposites. The resultant actuator can be triggered by moisture and exhibits a large deformation (>360°) and high response speed (2 s) due to the remarkable hygroscopic performance of MXene. Moreover, the actuator exhibits a high tensile strength (374 MPa) and good toughness (12.3 MJ/m3). Several potential uses of the prepared nanocomposite film have been demonstrated, including biomimetic motion, electrical switches, crawling robots, and conceptual robotic arms. This bioinspired assembly strategy provides an approach for the development of high-performance moisture-driven soft actuators and expands the application of moisture actuator devices in soft robots by addressing the current shortcomings of the low strength and poor durability of MXene-based actuators