Carbon Nanotube Networks Research Articles

Carbon nanotube reinforced biobased poly(urethane urea) covalent adaptable network composite

AbstractA solvent‐free approach was developed to incorporate carbon nanotube (CNT) into castor oil derived poly(urethane urea) (PPU) covalent adaptable network (CAN) based on dynamic piperidine‐urea bonds to fabricate CNT reinforced PPU composites. The approach includes two steps i.e., pre‐polymerization of castor with isophorone diisocyanate in flask and subsequent chain‐extension with 1,3‐bis(4‐piperidinyl)propane (PIP) in the presence of CNT in an internal mixer. The effect on CNT content of the morphology, mechanical property, stress relaxation, and reprocessability of the PPU/CNT composites was investigated in detail. The results demonstrated that CNT dispersed well in the PPU networks due to the applied strong shear force which facilitated the dispersion of CNT in the PPU matrix before cross‐linking. The well‐dispersed CNT reinforced the mechanical properties of PPU significantly and the Young's modulus (E) of the composites were enhanced significantly when the content of CNT was ≥6 wt% due to the formation of CNT network in the PPU matrix. When the content of CNT was 10 wt%, the E of PPU‐10%CNT was 927.59 ± 149.05 MPa, which was improved by ~60% compared to PPU. The reprocessability of the PPU network was remained although the stress relaxation rate was reduced with incorporation and increasing content of CNT. In addition, the PPU/CNT composites could be degraded chemically to recycle CNT through reaction of the dynamic piperidine‐urea bonds with additional PIP.

Boosting Thermoelectric Power Factor of Carbon Nanotube Networks with Excluded Volume by Co-Embedded Microparticles.

Carbon nanotube (CNT) networks embedded in a polymer matrix have been extensively studied as a flexible thermoelectric transport medium over the recent years. However, their power factor has been largely limited by the relatively inefficient tunneling transport at junctions between CNTs and the low-density conducting channels throughout the networks. This work demonstrates that significant power factor enhancements can be achieved by adding electrically insulating microscale particles in three-dimensional CNT networks embedded in the polymer matrix. When silica particles of a few μm diameters were co-embedded in single-walled CNT (SWCNT)-polydimethylsiloxane (PDMS) composites, both the electrical conductivity and the Seebeck coefficient were simultaneously enhanced, thereby boosting the power factor by more than a factor of six. We found that the silica microparticles excluded a large volume of the composite from the access of CNTs and caused CNT networks to form around them with the polymer as a binder, resulting in improved network connectivity and alignment of CNTs. Our theoretical calculations based on junction tunneling transport for three-dimensional CNT networks show that the significant power factor enhancement can be attributed to the enhanced tunneling with reduced junction distance between CNTs. Additional power factor enhancement by a factor of three was achieved by sample compression, which further reduced the mean junction distance to enhance tunneling but also reduced the geometric factor at the same time, limiting the enhancement of electrical conductivity.

Carbon nanotubes supported Cs-doped NiFe-layered double hydroxide nanosheets as efficient catalyst for oxygen evolution reaction

The sluggish kinetics of oxygen evolution reaction (OER) becomes one of the big obstacles for large-scale electrolytic water splitting. It is urgent to develop low-cost and efficient OER catalyst with fast reaction kinetics and low energy barrier. Herein, a novel OER catalyst of carbon nanotubes (CNT) supported cesium-doped NiFe-layered double hydroxide nanosheets (Cs–NiFe-LDH) is synthesized via a facile one-pot solvothermal reaction. The porous Cs–NiFe-LDH@CNT catalyst delivers an ultralow overpotential of 240 mV @10 mA cm−2, a small Tafel slope of 56.22 mV dec−1, and excellent long-term stability. The outstanding catalytic performance is mainly attributed to the synergistic effects of Cs doping and CNT network: the modification of the electronic structure of NiFe-LDH by Cs doping and the conductivity enhancement by CNT network can facilitate the electron transfer and kinetics; the Cs doping and CNT introduction can generate rich active sites; the nanoporous architecture can facilitate the ion diffusion and O2 bubble release. This work provides a synergistic strategy to design and synthesize transition metal based OER catalysts with low-cost, fast kinetics and good stability for water splitting.

Conductance of Metallic Carbon Nanotubes Network

The conductance of the carbon nanotubes (CNTs) network incorporates intertube and intratube conductance. Using the Anderson and tight-binding models, we calculate both conductances in the armchair and chiral metallic CNTs. We found that, at room temperature, the intertube conductance dominates in CNTs with larger localization lengths. Intertube conductance includes electronic and phonon-assisted junction conductance. We have revealed that the electronic conductance of a relaxed structure is around an order of magnitude larger than an unrelaxed structure. We found that the phonon-assisted conductance of armchair CNTs is comparable with their electronic conductance. However, the phonon-assisted conductance of chiral CNTs is around seven times smaller than the electronic conductance due to the large momentum needed for momentum relaxation. Furthermore, we address the dependence of junction conductance on the angle between the CNTs, the twist angle and sliding shift of the CNTs, the Fermi energy, and the applied bias voltage between CNTs. Our calculations perfectly match the experimentally measured temperature-dependent conductance using a single geometrical fitting parameter.

Lotus Leaf Derived NiS/Carbon Nanofibers/Porous Carbon Heterogeneous Structures for Strong and Broadband Microwave Absorption.

Developing composite materials with the synergistic effects of heterogeneous structures and multiple components is considered as a promising strategy to achieve high-performance electromagnetic wave (EMW) absorbers. To further satisfy the demand of broadband and strong microwave absorption, a novel NiS/carbon nanofibers (CNFs)/porous carbon composite is successfully synthesized by hydrothermal and chemical vapor deposition using lotus leaves as a biomass carbon source. A few carbon nanotubes (CNTs) and uniformly dispersed Ni nanocrystals have also been found in the hybrid. Benefiting from the porous structure derived from lotus leaves, the combination of dielectric NiS, conductive carbon nanomaterials, and magnetic Ni nanoparticles, together with the three-dimensional conductive network of CNFs and CNTs, the remarkable EMW absorption properties with a minimum reflection loss up to -67.65 dB have been achieved at merely 2.32 mm. Besides, the widest effective absorption band can reach 5.9 GHz with a thin thickness of 2.07 mm, covering almost the entire Ku band. In addition, under the incident angle of 31°, the radar cross-section reduction value of LNSF-600 can reach 42.88 dBm2. Therefore, this work provides an efficient and facile method for manufacturing outstanding biomass-derived EMW absorbers.

MOF-Derived Nitrogen-Doped Porous Carbon Polyhedrons/Carbon Nanotubes Nanocomposite for High-Performance Lithium-Sulfur Batteries.

Nanocomposites that combine porous materials and a continuous conductive skeleton as a sulfur host can improve the performance of lithium-sulfur (Li-S) batteries. Herein, carbon nanotubes (CNTs) anchoring small-size (~40 nm) N-doped porous carbon polyhedrons (S-NCPs/CNTs) are designed and synthesized via annealing the precursor of zeolitic imidazolate framework-8 grown in situ on CNTs (ZIF-8/CNTs). In the nanocomposite, the S-NCPs serve as an efficient host for immobilizing polysulfides through physical adsorption and chemical bonding, while the interleaved CNT networks offer an efficient charge transport environment. Moreover, the S-NCP/CNT composite with great features of a large specific surface area, high pore volume, and short electronic/ion diffusion depth not only demonstrates a high trapping capacity for soluble lithium polysulfides but also offers an efficient charge/mass transport environment, and an effective buffering of volume changes during charge and discharge. As a result, the Li-S batteries based on a S/S-NCP/CNT cathode deliver a high initial capacity of 1213.8 mAh g-1 at a current rate of 0.2 C and a substantial capacity of 1114.2 mAh g-1 after 100 cycles, corresponding to a high-capacity retention of 91.7%. This approach provides a practical research direction for the design of MOF-derived carbon materials in the application of high-performance Li-S batteries.

Short-Range Graphitic Nanodomains in Hypocrystalline Carbon Nanotubes Realize Fast Potassium Ion Migration and Multidirection Stress Release.

Defect-rich carbon materials are considered as one of the most promising anodes for potassium-ion batteries due to their enormous adsorption sites of K+ , while the realization of both rate capability and cycling stability is still greatly limited by unstable electrochemical kinetics and inevitable structure degradation. Herein, an Fe3+ -induced hydrothermal-pyrolysis strategy is reported to construct well-tailored hybrid carbon nanotubes network architecture (PP-CNT), in which the short-range graphitic nanodomains are in-situ localized in the pea pod shape hypocrystalline carbon. The N,O codoped hypocrystalline carbon region contributes to abundant defect sites for potassium ion storage, ensuring high reversible capacity. Meanwhile, the short-range graphitic nanodomains with expanded interlayer spacing facilitate stable K+ migration and fast electron transfer. Furthermore, the finite element analysis confirms the volume expansion caused by K+ intercalation can be availably buffered due to the multidirection stress release effect of the unique porous pea pod shape, endowing carbon nanotubes with superior structural integrity. Consequently, the PP-CNT anode exhibits superior potassium-storage performance, including high reversible capacity, exceptional rate capability, and ultralong cycling stability. This work opens a new avenue for the fabrication of advanced carbon materials for achieving durable and fast potassium storage.

Interfacial enhancement of CFRP/titanium alloy bonding joint by constructing a 3D interconnected CNTs network

Carbon fiber-reinforced polymer (CFRP)/titanium alloy joints offer exceptionally lightweight, superior fatigue behavior and impact resistance for aerospace applications. Nevertheless, Fiber-tear failure manifestly occurs in the CFRP/metal bonded joints due to the stress concentration of carbon fiber (CF) surfaces, and the adhesive cannot develop its full shear strength capacity, resulting in low shear strength. This drawback has limited the reliability of CFRP in full-scale structures where adhesive bonding is essential. In this study, a three-dimensional (3D) interconnected carbon nanotubes (CNTs) network was constructed on the CFs on the surface of CFRP to release the stress concentration. Carboxyl functionalized CNTs were grown on the surface of CFs, and then the CNTs were arranged in the adhesive to form a 3D network using ultrasonic-powered adhesive injection (UPAI) process. The interfacial bonding strength can reach up to 29.51 MPa, increasing by 30.7%. The growth of CNTs was verified by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The ultrasonic process can effectively promote the construction of 3D coiled/entangled and vertically aligned CNT structures, providing a more complex crack propagation path for the energy dissipation capability. FESEM and energy dispersive spectroscopy (EDS) tests of the cross sections of CFRP/titanium (Ti) alloy joints revealed that the ultrasonic process promoted mechanical anchoring owing to improved wettability and increased acoustic pressure within the adhesive. These results provide insights into future high-performance CFRP/metal hybrid joining technology of lightweight structures.

Anisotropic and Highly Sensitive Flexible Strain Sensors Based on Carbon Nanotubes and Iron Nanowires for Human-Computer Interaction Systems.

Flexible strain sensors for multi-directional strain detection are crucial in complicated hman-computer interaction (HCI) applications. However, enhancing the anisotropy and sensitivity of the sensors for multi-directional detection in a simple and effective method remains a significant issue. Therefore, this study proposes a flexible strain sensor with anisotropy and high sensitivity based on a high-aspect-ratio V-groove array and a hybrid conductive network of iron nanowires and carbon nanotubes (Fe NWs/CNTs). The sensor exhibits significant anisotropy, with a difference in strain detection sensitivity of up to 35.92 times between two mutually perpendicular directions. Furthermore, the dynamic performance of the sensor shows a good response rate, ranging from 223 ms to 333 ms. The sensor maintains stability and consistent performance even after undergoing 1000 testing cycles. Additionally, the constructed flexible strain sensor is tested using the remote control application of a trolley, demonstrating its high potential for usage in practical HCI systems. This research offers a significant competitive advantage in the development of flexible strain sensors in the field of HCI.

Geometrical and chemical effects on the electrochemistry of single-wall carbon nanotube (SWCNT) network electrodes

Single-wall carbon nanotube (SWCNT) network is a promising electrode material for bio detection. Unfortunately, the associations between their physical as well as chemical properties and observed electrochemical performance are not known. This hinders any systematic optimization of the network properties towards specific analytes. Here we present a consistent physicochemical and electrochemical characterization of differently treated SWCNT networks. The results unambiguously show that (i) even if the electrochemical properties of different electrodes are practically identical when assessed by surface insensitive outer sphere redox (OSR) probes their behavior with inner sphere redox (ISR) probes can be drastically different. Further, (ii) the choice of the modification method (structural, chemical, electrochemical) heavily depends on nature of the target analyte, which are typically ISR probes. Although, (iii) chemical changes in the carbon phase appeared to be minor, effects of different treatments on oxidation states of Fe appeared to have a strong effect on the electrochemical performance of the networks in the case of ISR probes.

A coarse‐grained molecular dynamics study on the mechanical behavior of carbon nanotubes reinforced vulcanized natural rubber composites

AbstractIn the present study, coarse‐grained (CG) molecular models of carbon nanotubes (CNTs) strengthened vulcanized natural rubber (VNR) composites are constructed to systematically investigate the effects of length, inter‐tube cross‐linking, and polymer‐grafting of CNTs on the stress–strain behavior of VNR composites under uniaxial tension. The interfacial CG force field between CNTs and VNR is derived via the energy matching approach. The results demonstrate that increasing the length of CNTs is able to effectively enhance the mechanical performance of VNR composites, and the reinforcing efficiency increases gradually and tends to stabilize with increasing CNT length. Moreover, the cross‐linking and polymer‐grafting of CNTs are also effective approaches to significantly enhance the mechanical performance of VNR composites. The enhancement mechanism of CNTs is interpreted from the perspective of CNT networks, VNR networks, CNT‐VNR interface networks, and the interfacial load‐transfer behavior. Specifically, the dispersion of CNTs, the orientation of CNTs and VNR molecular chains, and the wrapping and interlocking behaviors between CNTs and the VNR matrix reveal a detailed structure‐mechanics relationship of CNTs‐reinforced VNR composites at the molecular level. These findings present theoretical instruction for the structural design of high‐performance rubber composites.Highlights A coarse‐grained model of carbon nanotube‐natural rubber composites is built. The composite network structures are quantitatively characterized. The length, cross‐linking, and grafting effects of carbon nanotubes are studied. The reinforcement mechanisms of carbon nanotubes are revealed.

Water-repellent and self-attachable flexible conductive patch

Achieving exceptional water-repellency and reliable reversible adhesion is crucial for the development of wearable flexible electronics. However, simultaneously achieving these properties presents a significant challenge, as water-repellency requires maximizing the presence of air while robust adhesion necessitates enhancing the solid fraction. In this study, we present a flexible and transparent conductive patch that addresses this challenge by offering simultaneous robust superhydrophobicity and strong adhesion in both dry and wet conditions. The device incorporates a unique combination of overhang micropillars, microgrids and a percolating network of carbon nanotubes. The proposed patch demonstrates outstanding water repellency with a contact angle exceeding 150°, while delivering impressive dry adhesion (>200 kPa) and wet adhesion (>150 kPa) performance. Furthermore, the device exhibits tunable electrical conductivity and optical transmittance.

One-step method for the fabrication of pure and metal-decorated densified CNT films for effective electromagnetic interference shielding

Light-weight, thin, and robust electromagnetic shielding materials with high electrical conductivity are needed for advanced modern electronics and telecommunication technologies to protect circuits from electromagnetic interference. Carbon nanotubes (CNT) are ideal candidates for electromagnetic shielding materials due to their excellent mechanical strength, high electrical conductivity, and light weight. However, the relatively poor electrical conductivity of CNT films, a result of the many points of contact resistance between neighboring CNTs, is an obstacle towards their utilization as a shielding material. Here, we propose a facile CNT film fabrication method that enhances the conductivity of CNT films by collapsing the separation between neighboring CNTs (i.e., densifying the material) in the CNT network. The dense CNT films resulting from this facile method exhibit high electrical conductivity (∼106 S m-1), and achieve excellent shielding of 99.999992% (71 dB) at frequencies between 8.2 GHz and 12.4 GHz with a thickness of 14.3 μm. The remarkable absolute shielding effectiveness (3.50 × 105 dB cm-2 g-1) is due to the material's low density (i.e., ∼1.0 g/cm3), thinness (i.e., 1.3–14.3 μm), and metal-like conductivity. Also, the produced CNT sheet is an ideal substrate for gold decoration that can dramatically enhance the EMI shielding performance further (EMI SE increased from 43.90 dB in the loose film to 56.67 dB in the dense film, which further increased to 66.12 dB when the dense CNT film was coated with a thin gold layer). The outstanding properties of gold-decorated dense CNT films make them strong candidates to meet the electromagnetic shielding needs of modern cutting-edge, lightweight, and compact electronic devices.

Viscoelastic, ductile and repairable carbon nanotube films formed with CNT/PEI double networks containing branched polyethylenimine

Manipulating nanostructure assemblies is important in using them as structural and functional materials. Carbon nanotubes (CNTs) lack the ability to reconstruct their entangled network. In this work, we report a strategy with which to realize efficient manipulation of CNT networks by forming double networks with branched polyethylenimine (PEI). The double network was highly viscoelastic and ductile and enabled efficient film stretching or creeping for CNT alignment, which dramatically improved the mechanical strength of the CNT films. Due to the viscous drag from the polymer network, the CNTs showed enhanced movability in reconstructing new networks, which made the film repairable. The repairability resulted from the branched polymeric structure. This double-networking strategy provides a new way to manipulate CNT assemblies for high-performance applications.

In-situ construction of plasma-pretreated CNT networks endow the LPDS dual-layer coating with advanced thermal management and anti-static properties

Carbon nanotubes (CNTs) for temperature regulation have been proven to be promising for passive radiative heat dissipation. However, it remains a considerable challenge to assemble a CNTs layer in situ while simultaneously achieving horizontal electrical conductivity, vertical electrical insulation, and radiative heat dissipation. Herein, plasma pretreatment was employed to functionalize CNTs in an aqueous solution, thus improving their dispersion capability. Subsequently, a liquid-plasma-assisted particle deposition and sintering (LPDS) technology was proposed to prepare a dual-layer coating with an Al2O3-P2O5-SiO2-In2O3 glass system embedded with crystalline indium tin oxide (ITO) as the porous bottom layer and ITO-CNTs as the top layer on the aluminum alloy surface. The results show that plasma pretreatment significantly increases the deposition amount of ITO nanoparticles and functionalized CNTs on the coating surface, resulting in the transition from a single-layer composite coating to a dual-layer coating. The surface micro-/nano hierarchical structure favors strong absorptance/emittance, exhibiting a high infrared emittance of 0.94 (3-20 μm) and high solar absorptance of 0.92 (0.2-2.5 μm). Meanwhile, the surface balance temperature of the dual-layer coating is about 392 K, which is 146 K lower than that of aluminum alloy. Furthermore, the top conductive ITO-CNTs layer contributes to the low surface resistivity of 3.46×102 Ω, while the glass phase of the bottom layer ensures vertical electrical insulation with a volume resistance of 4.20×107 Ω. The process provides a new path for preparing thermal control coatings with anti-static function.

Theoretical Prediction of Electrical Conductivity Percolation of Poly(lactic acid)-Carbon Nanotube Composites in DC and RF Regime.

Polymer composites based on polylactic acid (PLA) reinforced with 0.25-5 wt.% of carbon nanotubes (CNTs) were synthesized by melt blending. The static (DC) and microwave (RF) electrical conductivity have been investigated on the PLA-CNT composites. The electrical percolation threshold has been theoretically determined using classical models of percolation in order to predict the conductivity of the different nanocomposites. Through the fitting process, it has been found that the percolation threshold is obtained at 1 wt.% of CNTs in the DC regime and reached below 0.25 wt.% of CNTs in the microwave regime. Among the Mamunya, McLachlan, or GEM models, the McCullough model remarkably fits the experimental DC and RF electrical conductivities. The obtained results are correlated to the electrical properties of a range of CNT-based composites, corresponding to the percolation threshold required for a three-dimensional network of CNTs into the polymer matrix.

In-situ strain characterization and stress analysis of SnO2@graphite@CNT electrodes for lithium-ion batteries by digital image correlation method

In this study, SnO2@graphite@CNT composite was synthesized by growing SnO2 nanoparticles within the interconnected three-dimensional network of graphite and carbon nanotubes using an acoustic chemistry method and a followed annealing treatment. As anode material for lithium-ion batteries, the composite exhibits high specific capacity and excellent cycling stability. The deformation behavior of the SnO2@graphite@CNT electrodes was in-situ monitored and recorded during discharge-charge process, and the strain fields onto the electrode surface was analyzed using digital image correlation technique. The dynamic evolution of plane stress in the electrode was evaluated by combining strain data with a mechano-electrochemical constitutive equation, and the contributions of mechanical and electrochemical parts to the plane stress also be discussed, respectively. The results provide valuable insights into the volume deformation behavior and mechano-electrochemical failure mechanism of SnO2-based electrodes for lithium-ion batteries.

In-situ Electropolymerized Three-Dimensional Microporous Cobalt-Porphyrin Nanofilm for Highly Effective Molecular Electrocatalytic Reduction of Carbon Dioxide.

Electrocatalytic CO2 reduction reaction (CO2 RR) based on molecular catalysts, e.g., cobalt porphyrin, is a promising approach to enhance carbon cycle and mitigate climate crisis. However, the electrocatalytic performance and accurate evaluations remains problems because of either the low loading amount or the low utilization rate of the electroactive CoN4 sites. W e herein synthesized a monomer, cobalt(II)-5,10,15,20-tetrakis(3,5-di(thiophen-2-yl)phenyl)porphyrin (CoP), electropolymerized it onto the crosslinked carbon nanotubes (CNTs) networks, affording a molecular electrocatalyst of three-dimensional (3D) microporous nanofilm (EP-CoP, 2∼3nm thickness) with highly dispersed CoN4 sites. The new electrocatalyst shortens the electron transfer pathway, accelerates the redox kinetics of CoN4 sites and improves the durability in the electrocatalytic CO2 RR. From the intrinsic redox behavior of CoN4 sites, the effective utilization rate is obtained as 13.1%, much higher than that of the monomer assembled electrode (5.8%), and the durability is also promoted dramatically (> 40h) in a H-type cell. In a commercial flow cell, EP-CoP can achieve a faradic efficiency for CO (FECO ) over 92% at an overpotential of 160mV. At a higher overpotential of 620mV, the working current density can reach 310mA cm-2 with a high FECO of 98.6%, representing the best performance for electrodeposited molecular porphyrin electrocatalysts. This article is protected by copyright. All rights reserved.

Growing Electrocatalytic Conjugated Microporous Polymers on Self-Standing Carbon Nanotube Films Promotes the Rate Capability of Li-S Batteries.

Lithium-sulfur (Li-S) batteries hold great promise for widespread application on account of their high theoretical energy density (2600Wh kg-1 ) and the advantages of sulfur. Practical use, however, is impeded by the shuttle effect of polysulfides along with sluggish cathode kinetics. it is reported that such deleterious issues can be overcome by using a composite film (denoted as V-CMP@MWNT) that consists of a conjugated microporous polymer (CMP) embedded with vanadium single-atom catalysts (V SACs) and a network of multi-walled carbon nanotubes (MWNTs). V-CMP@MWNT films are fabricated by first electropolymerizing a bidentate ligand designed to coordinate to V metals on self-standing MWNT films followed by treating the CMP with a solution containing V ions. Li-S cells containing a V-CMP@MWNT film as interlayer exhibit outstanding performance metrics including a high cycling stability (616mA h g-1 at 0.5 C after 1000 cycles) and rate capability (804mA h g-1 at 10 C). An extraordinary area-specific capacity of 13.2mA h cm-2 is also measured at a high sulfur loading of 12.2mg cm-2 . The underlying mechanism that enables the V SACs to promote cathode kinetics and suppress the shuttle effect is elucidated through a series of electrochemical and spectroscopic techniques.

Competing Effects of Radio Frequency Fields on Carbon Nanotube/Resin Systems: Alignment versus Heating

AbstractThis work shows that radio‐frequency (RF) fields can simultaneously align carbon nanotubes (CNTs) dispersed in a resin and induce Joule heating to cure the resin. The timescales of alignment and curing using RF heating are numerically computed and compared at different field strengths in order to determine a temperature where alignment happens before the matrix crosslinks. Composites are experimentally fabricated at the desired target temperature and are optically analyzed and quantified; the CNT network is successfully aligned in the direction of the applied electric field. This methodology can be used to create composites where the local alignment can be varied across the sample. Composites fabricated using RF fields have higher electrical conductivity in the direction of the aligned CNTs than an oven‐cured, randomly aligned sample. Also, RF‐cured nanocomposites exhibit higher tensile strength and modulus in the direction of alignment compared to an oven‐cured sample. Finally, it is further demonstrated how this methodology can be coupled with a direct ink writing additive manufacturing process to induce alignment in any desired direction, even orthogonal to the shear forces in the extrusion direction.