Soft Materials Research Articles

Programming gel automata shapes using DNA instructions

The ability to transform matter between numerous physical states or shapes without wires or external devices is a major challenge for robotics and materials design. Organisms can transform their shapes using biomolecules carrying specific information and localize at sites where transitions occur. Here, we introduce gel automata, which likewise can transform between a large number of prescribed shapes in response to a combinatorial library of biomolecular instructions. Gel automata are centimeter-scale materials consisting of multiple micro-segments. A library of DNA activator sequences can each reversibly grow or shrink different micro-segments by polymerizing or depolymerizing within them. We develop DNA activator designs that maximize the extent of growth and shrinking, and a photolithography process for precisely fabricating gel automata with elaborate segmentation patterns. Guided by simulations of shape change and neural networks that evaluate gel automata designs, we create gel automata that reversibly transform between multiple, wholly distinct shapes: four different letters and every even or every odd numeral. The sequential and repeated metamorphosis of gel automata demonstrates how soft materials and robots can be digitally programmed and reprogrammed with information-bearing chemical signals.

Ion‐Specific Interactions Engender Dynamic and Tailorable Properties in Biomimetic Cationic Polyelectrolytes

AbstractBiomaterials such as spider silk and mussel byssi are fabricated by the dynamic manipulation of intra‐ and intermolecular biopolymer interactions. Organisms modulate solution parameters, such as pH and ion co‐solute concentration, to effect these processes. These biofabrication schemes provide a conceptual framework to develop new dynamic and responsive abiotic soft material systems. Towards these ends, the chemical diversity of readily available ionic compounds offers a broad palette to manipulate the physicochemical properties of polyelectrolytes via ion‐specific interactions. In this study, we show for the first time that the ion‐specific interactions of biomimetic polyelectrolytes engenders a variety of phase separation behaviors, creating dynamic thermal‐ and ion‐responsive soft matter that exhibits a spectrum of physical properties, spanning viscous fluids to viscoelastic and viscoplastic solids. These ion‐dependent characteristics are further rendered general by the merger of lysine and phenylalanine into a single, amphiphilic vinyl monomer. The unprecedented breadth, precision, and dynamicity in the reported ion‐dependent phase behaviors thus introduce a broad array of opportunities for the future development of responsive soft matter; properties that are poised to drive developments in critical areas such as chemical sensing, soft robotics, and additive manufacturing.

Evaluation of Tensile Bond Strength of Nanoparticle Reinforced Soft Liner Materials: A Pilot Study

OBJECTIVE: The aim of this study is to evaluate the tensile bond strength between polymethyl methacrylate (PMMA) surfaces and autopolymerized silicon-based soft lining materials with 1% w/w Titanium dioxide (TiO2) and Hydroxyapatite (HA) nanoparticles added. MATERIALS AND METHODS: For the tensile test, 60 pieces of acrylic (Meliodent, Bayer Dental, Newbury, England) samples of 30 × 10 × 10 mm3 dimensions were prepared using metal molds. Acrylic surfaces were sanded with silicon carbide sandpapers of 500, 1000, 1500, and 2000 grids to ensure standardization. After the samples were placed back in the metal mold, adhesive (Detax, Germany) was applied to the surfaces that would come into contact with the soft lining. Soft lining materials (Mollosil, Detax, Ettlingen, Germany) to which 1% by weight TiO2 and 1% HA nanoparticles were added were polymerized by placing them between two acrylic blocks. For the tensile test, a total of 30 samples were obtained, with 10 samples in each group (n=10). The specimens were placed on the holder end of the universal test device and force was applied until failure occurred. RESULTS: The tensile bond strength (0,86 ± 0,21 MPa) in the TiO2 nanoparticle-added group was found to be significantly higher than the control group (0,65 ± 0,14 MPa) (p<0.05). There is no significant difference between the control group and the HA nanoparticle-added group (0.65 ± 0.1 MPa) (p˃0.05). CONCLUSION: It was observed that the addition of nanoparticles increased the tensile strength. However, further studies are needed to evaluate the effect of nanoparticle addition on other mechanical and physical properties of soft liners.

PENGARUH LIKUIDITAS,SOLVABILITAS,DAN STRUKTUR MODALTERHADAP NILAI PERUSAHAAN PADA SEKTOR FARMASI YANG TERDAFTAR DI BEI PERIODE 2018-2021

Well-established pharmaceutical companies always try to implement the company's activity to achieve the company's goals, ie. increase the value of the company. The goals of the company can be achieved mainly thanks to the high profitability of the company, which is reflected in theprofit margin of the company, which is mainly supported by financial resources. The study used descriptive quantitative methods with a test measure of 32 observational data taken from a sample size of 8 companies and multiplied by 4 years of research. The purpose of this study is to see the effect of liquidity, solvency and capital structure on the value of a pharmaceutical company listed on IDX in the period 2018-2021. The results of the study show that the liquid variable has a partially negative and significant effect on the value variable of the pharmaceutical company listed by BEI for the period 2018-2021. The solvency variable has a partially positive and significant effect on the value variable of the pharmaceutical sector listed in the BEI in the period 2018-2021. 2021. The variable of capital structure has a partial effect on the enterprise value variable in the pharmaceutical industry listed on IDX for the period 2018-2021. The variables liquidity, solvency and capital structuresimultaneously positively and significantly influence the change in the value of the company in the pharmaceutical segment recorded on the IDX within the period 2018-2022.

Analytical model of friction at low shear rates for soft materials in 3D printing.

The biological properties of silicone elastomers such as polydimethylsiloxane (PDMS) have widespread use in biomedicine for soft tissue implants, contact lenses, soft robots, and many other small medical devices, due to its exceptional biocompatibility. Additive manufacturing of soft materials still has significant challenges even with major advancements that have occurred in development of these technologies for customized medical devices and tissue engineering. The aim of this study was to develop a mathematical model of tangential stress in relation to shear stress, shear rate, 3D printing pressure and velocity, for non-Newtonian gels and fluids that are used as materials for 3D printing. This study used FENE (finitely extensible nonlinear elastic model) model, for non-Newtonian gels and fluids to define the dependences between tangential stress, velocity, and pressure, considering viscosity, shear stress and shear rates as governing factors in soft materials friction and adhesion. Experimental samples were fabricated as showcases, by SLA and FDM 3D printing technologies: elastic polymer samples with properties resembling elastic properties of PDMS and thermoplastic polyurethane (TPU) samples. Experimental 3D printing parameters were used in the developed analytical solution to analyse the relationships between governing influential factors (tangential stress, printing pressure, printing speed, shear rate and friction coefficient). Maple software was used for numerical modelling. Analytical model applied on a printed elastic polymer, at low shear rates, exhibited numerical values of tangential stress of 0.208-0.216 N m - 2 at printing velocities of 0.9 to 1.2 mm s - 1, while the coefficient of friction was as low as 0.09-0.16. These values were in accordance with experimental data in literature. Printing pressure did not significantly influence tangential stress, whereas it was slightly influenced by shear rate changes. Friction coefficient linearly increased with tangential stress. Simple analytical model of friction for elastic polymer in SLA 3D printing showed good correspondence with experimental literature data for low shear rates, thus indicating possibility to use it for prediction of printing parameters towards desired dimensional accuracy of printed objects. Further development of this analytical model should enable other shear rate regimes, as well as additional soft materials and printing parameters.

Entropy-favorable adsorption of polymer-grafted nanoparticles at fluid-fluid interfaces.

The adsorption of polymer-grafted nanoparticles at interfaces is a problem of fundamental interest in physics and soft materials. This adsorption behavior is governed by the interplay between interaction potentials and entropic effects. Here, we use molecular dynamics simulations and umbrella sampling methods to study the adsorption behavior of a Janus-like homopolymer-grafted nanoparticle at fluid-fluid interfaces. By calculating the potential of the mean force as the particle moves from fluid A to the interface, the adsorption energy Ea can be obtained. When two homopolymer chains with types A and B are grafted to the opposite poles of the particle, Ea shows a scaling behavior with respect to chain length N: Ea ∝ N0.598. This is determined by the interactions between polymers and fluids. The enthalpy dominates, and the entropy effects mainly come from the rotational entropy loss of the polymer-grafted nanoparticle at interfaces, which disfavors the stabilization of particles at interfaces. When the grafted polymer number m is large, the adsorption energy exhibits a linear dependence on m. While the enthalpy dominates the behavior, the entropy becomes significant at a larger chain length of N = 15, where the configurational entropy of the polymer chains dominates the entropy of the system. The globule-coil transition occurs when polymers move from poor solvents to good solvents, increasing the configurational entropy and favoring the stabilization of particles at interfaces. Our study provides novel insights into the stabilization mechanism of polymer-grafted nanoparticles at interfaces and reveals the stabilization mechanism favored by the configurational entropy of grafted polymer chains.

Tribological Performance of Soft Magnetic Composite Materials for Gas Turbine Applications

Abstract Soft magnetic composites (SMCs) have gained attention in the last years of their usage in more compact and powerful electromechanical systems. These materials are used to combine the application of metallic material to the capability of generating (without external supply) a magnetic field. Automotive and aerospace technologies push the applications of these original materials to even higher power and mechanical stress to reduce the number of components, the size, and, in turn, the weight of complex systems. Considering gas turbine application, SMCs were formerly developed for bearings, but in the last decades, the new era of gas turbine electrification (e.g., hybrid-electric fly) has determined the need for mechanical improvement of such materials. At the same time, the reliability of soft magnetic material has to be discovered to avoid failure and reduce the maintenance schedule. In the present work, tribological behaviors of SMCs were investigated by standard wear tests. Two different types of SMSc were prepared through the powder metallurgy technique. Tests were conducted by a tribometer using a ball-on-disk configuration in lubricated condition. The effect of oil temperature and applied load were investigated. In addition, an extensive post-mortem analysis was conducted on the worn surface to recognize the mechanisms responsible for the deterioration of the materials. The results showed the effects of the oil viscosity on the useful operating life of the SMCs. Removal mechanisms depend on the load conditions, and the proper selection of the oil characteristics and load was assessed.

Nonequilibrium relaxation of soft responsive colloids.

Stimuli-responsive macromolecules display large conformational changes during their dynamics, sometimes switching between states. Such a multi-stability is useful for the development of soft functional materials. Here, we introduce a mean-field dynamical density functional theory for a model of responsive colloids to study the nonequilibrium dynamics of a colloidal dispersion in time-dependent external fields, with a focus on the coupling of translational and conformational dynamics during their relaxation. Specifically, we consider soft Gaussian particles with a bimodal size distribution between two confining walls with time-dependent (switching-on and off) external gravitational and osmotic fields. We find a rich relaxation behavior of the systems in excellent agreement with particle-based Brownian dynamics computer simulations. In particular, we find time-asymmetric relaxations of integrated observables (wall pressures, mean size, and liquid center-of-mass) for activation/deactivation of external potentials, respectively, which are tunable by the ratio of translational and conformational diffusion time scales. Our work thus paves the way for studying the nonequilibrium relaxation dynamics of complex soft matter with multiple degrees of freedom and hierarchical relaxations.

Command of three-dimensional solitary waves via photopatterning.

Multidimensional solitons are prevalent in numerous research fields. In orientationally ordered soft matter system, three-dimensional director solitons exemplify the localized distortion of molecular orientation. However, their precise manipulation remains challenging due to unpredictable and uncontrolled generation. Here, we utilize preimposed programmable photopatterning in nematics to control the kinetics of director solitons. This enables both unidirectional and bidirectional generation at specific locations and times, confinement within micron-scaled patterns of diverse shapes, and directed propagation along predefined trajectories. A focused dynamical model provides insight into the origins of these solitons and aligns closely with experimental observations, underscoring the pivotal role of anchoring conditions in soliton manipulation. Our findings pave the way for diverse fundamental research avenues and promising applications, including microcargo transportation and optical information processing.

Temperature-induced structure evolution in monocrystalline and polycrystalline cobalt via molecular dynamics simulations

The structure transition of metallic melt strongly depends on temperature and significantly influences the comprehensive properties. However, observing the structure change in experiments is still challenging. Here, molecular dynamics is used to study the melting process and microstructural evolution in single crystal and polycrystal cobalt (Co). The results indicate that the melting process of single crystal structure starts from 1870 K and lasts for a very short period, while the polycrystal melts from about 1760 to 1870 K. In polycrystal Co, the melting initially occurs in grain boundaries, and the melting temperature shows a positive correlation with grain size. An interesting solidification phenomenon occurs on the surface of big grains in the beginning of melting process. The coordination number increasing from 12 to about 13.4 near melting point proves the local expansion of the first coordination shell, indicating the structural evolution from long-range order to short-range order in the continuous heating process. The common neighbor sub-cluster index and Voronoi polyhedron demonstrate the short-range icosahedron structures, while these polyhedrons become polydisperse and isolated in Co liquid. The findings ignite the investigation of the liquid structure origin of crystal materials and extend the understanding of the atomic structure evolution in melting.

Comparison of Bond Strength of Soft Denture Liner on the Denture Base Materials Produced by Different Methods and Effect of Thermocycling

Aim: This study set out to determine the tensile bond strength between denture bases (produced by 3D printing technology, conventional technique, and computer-aided design and computer-aided manufacturing [CAD/CAM] milled) and silicone-based soft lining material. The consequence of thermocycling on the bonding strength was also investigated. Materials and Methods: The bonding between denture foundation materials produced through three distinct techniques (conventional, CAD/CAM milled, and 3D printed) and silicone-based soft lining material was examined. Before tensile testing, half of the samples underwent thermocycling (5–55°C, 5,000 cycles) in 37°C distilled water for 48 hours. A universal testing apparatus employed a crosshead speed of 5 mm/min. The failure type was identified visually, and the maximum tensile strength was noted. The Shapiro-Wilk test and analysis of variances ( P = .05) were used to assess the statistics. Results: CAD/CAM milled denture base material (1.56 ± 0.62/1.36 ± 0.16 MPa) showed higher bond strength values than the other denture bases in the tensile test conducted before and after thermocycling ( P < .001). The denture base material made conventionally had the lowest bond strength (1.02 ± 0.24/0.77 ± 0.1 MPa) ( P < .001). The tensile bond strength values of the conventional and 3D printing groups showed a statistically significant drop before and after thermocycling ( P = .001). Regardless of thermocycling, adhesive failure was primarily seen in all groups (76.6%). Conclusion: Compared to conventionally produced denture bases, the bond strength of soft relining materials to CAD/CAM milled and 3D printed denture base is different. In denture base materials that are conventionally, CAD/CAM and 3D printed, the thermocycling method reduced bonding strength values.

Nickel‐Catalyzed [2+2+2] Cyclotrimerization of Alkynes and Other Unsaturated Systems: A Literature Overview

Transition metal‐catalyzed [2+2+2] cyclotrimerization provides easy access to carbocycles and heterocycles in a single operation with complete atom economy. In recent years, nickel catalysis has emerged as a powerful tool for constructing fused arenes and heteroarenes with high regio‐/chemoselectivity and functional group tolerance. This review highlights the historical perspective and advances made in recent years in nickel‐catalyzed [2+2+2] cycloadditions of alkynes, diynes, and various unsaturated systems. The catalytic activity of the nickel complexes, such as Ni‐phosphine, Ni‐NHC, Ni‐pincer, Ni‐diimine, etc, and their mechanistic insights have been thoroughly examined. Highly substituted arenes have broad applications in pharmaceuticals and soft materials. The applications of cyclotrimerization in these areas have been illustrated.

Differential growth-induced center waving of film-substrate system

Various intriguing morphological patterns emerge on the surfaces of growing, developing, or aging tissues, organs, and colonies of microorganisms. Our research draws inspiration from biological growth processes and applies differential growth to film-substrate systems. The strain mismatch induced by this approach leads to distinctive buckling patterns. Through a combination of finite element analysis (FEA) and theoretical analysis, we derive a comprehensive expression for the strain energy in a buckled film-substrate system subjected to differential growth. By solving the energy equations, our study investigates the intricate interplay of material properties, growth functions, and geometric characteristics. This exploration provides valuable insights into the deformations induced by growth in membrane structures and soft materials. Additionally, we establish a phase diagram that characterizes the buckling patterns. It opens avenues for innovative geometric design and 3D self-assembly techniques. Furthermore, our findings have the potential to inspire applications in fields such as soft robotics and flexible electronics.

Research of a spring soft wheat collection material based on ear’s structure and grain quality elements

In modern conditions of high intensification of agriculture, the key task at all stages of development is to increase the volume of grain produced. This requires constant improvement of the varietal composition of production fields. When creating a new variety, it is necessary to comprehensively study the collection nursery for parental forms of important elements of grain structure and quality. In these scientific studies, 32 varieties of spring soft wheat were studied at the Institute of Seed Production and Agricultural Technologies in the Ryazan region. Standard variety Agata. From the studied varieties, the following varieties were identified: by the length of the ear Arsei, Margarita, Simbirtsit, Uralosibirskaya, Darnitsa, which are 19.5–31.2% higher than the standard, by the number of grains KVS Torridon, KVS Aquilon, Margarita, Ethos, Ekada 70, Odeta, and Kinelskaya Otrada, Uralosibirskaya, Darnitsa, Hercules exceeds the standard by 5.29–36.77%, by weight of grain per ear KVS Akvilon, KVS Torridon, Odeta, Margarita, Simbirtsit, Kalispero, Mary, Hercules, Uralosibirskaya, Ethos, Darnitsa, Kinelskaya Otrada, Kazan Yubileinyaya with indicators above the standard by 1.88–20.63%, in terms of protein content in grain Zlata, Novosibirskaya 29, Uralosibirskaya, Siberian Alliance, Sable, Chelyaba 2 above the standard by 0.42–2.01%, according to the gluten content in grain Novosibirskaya 29, Sable, Chelyaba 2 is 2.5–3.2% higher than the standard; by weight of 1000 grains Odeta, Siberian Alliance, Margarita, Simbirtsit, Burlak is 2.5–3.2% higher than the standard.

The lysogenic filamentous Pseudomonas bacteriophage phage Pf slows mucociliary transport

Abstract Pseudomonas aeruginosa is a major pulmonary pathogen causing chronic pulmonary infections in people with cystic fibrosis (CF). The P. aeruginosa filamentous and lysogenic bacteriophage, Pf phage, is abundant in the airways of many people with CF and has been associated with poor outcomes in a cross-sectional cohort study. Previous studies have identified roles for Pf phage in biofilm formation, specifically forming higher-order birefringent, liquid crystals when in contact with other biopolymers in biofilms. Liquid crystalline biofilms are more adherent and viscous than those without liquid crystals. A key feature of biofilms is to enhance bacterial adherence and resist physical clearance. The effect of Pf phage on mucociliary transport is unknown. We found that primary CF and non-CF nasal epithelial cells cultured at air–liquid interface treated with Pf phage exhibit liquid crystalline structures in the overlying mucus. On these cell cultures, Pf phage entangles cilia but does not affect ciliary beat frequency. In both these in vitro cell cultures and in an ex vivo porcine trachea model, introduction of Pf phage decreases mucociliary transport velocity. Pf phage also blocks the rescue of mucociliary transport by CF transmembrane conductance regulator modulators in CF cultures. Thus, Pf phage may contribute to the pathogenesis of P. aeruginosa-associated CF lung disease via induction of liquid crystalline characteristics to airway secretions, leading to impaired mucociliary transport. Targeting Pf phage may be useful in treatment CF as well as other settings of chronic P. aeruginosa infections.

Tough, Slippery, and Low-Permeability Multilayer Hydrogels Modified by Anisotropic Fiber Membrane for Soft Tissue Replacement.

Hydrogels with sustained lubrication, high load-bearing capacity, and wear resistance are essential for applications in soft tissue replacements and soft material devices. Traditional tough or lubricious hydrogels fail to balance the lubrication and load-bearing functions. Inspired by the gradient-ordered multilayer structures of natural tissues (such as cartilage and ligaments), a tough, smooth, low-permeability, and low-friction anisotropic layered electrospun fiber membrane-reinforced hydrogel was developed using electrospinning and annealing recrystallization. This hydrogel features a stratified porous network structure of varying sizes with tightly bonded interfaces, achieving an interfacial bonding toughness of 1.6 × 103 J/m2. The anisotropic fiber membranes, mimicking the orderly fiber structures within soft tissues, significantly enhance the mechanical properties of the hydrogel with a fracture strength of 20.95 MPa, a Young's modulus of 29.64 MPa, and a tear toughness of 37.94 kJ/m2 and reduce its permeability coefficient (6.1 × 10-17 m4 N-1 s-1). Meanwhile, the hydrogel demonstrates excellent solid-liquid phase load-bearing characteristics, which can markedly improve the tribological performance. Under a contact load of 4.1 MPa, the anisotropic fiber membrane-reinforced hydrogel achieves a friction coefficient of 0.036, a 219% reduction compared with pure hydrogels. Thus, the superior load-bearing and lubricating properties of this layered hydrogel underscore its potential applications in soft tissue replacements, medical implants, and other biomedical devices.

Design and FEA verification of high dimensional and multi-field smart soft material

Abstract We designed a sophisticated smart soft tissue material that simulates the properties of biological soft tissue and detects three-dimensional force. Inspired by electronic skin, this material uses capacitive pressure sensors and multi-layer sensor packaging. Finite element analysis and multi-field simulation were employed for structural design and verification. The study evaluated the theory and practicality of a flexible capacitive 3D force sensor for detecting pressure and shear force. Mechanical and electrical properties were confirmed through force and electric field simulations. The 3D force detection method proved feasible, achieving sensitivity levels of 10−4 kPa −1 in the X and Y directions, and 10−3 kPa −1 in the Z direction, demonstrating the effectiveness of our design.

Hybridizing Shear-Stiffening Gel and Chemically-Strengthened Ultrathin Glass Sheets for Flexible Impact-Resistant Armor.

Traditional anti-impact armors and shields are normally made of stiff and hard materials and therefore deficient in flexibility. This greatly limits their applications in protecting objects with complex geometries or significant deformability. Flexible armors can be developed with the application of hard platelets and soft materials, but the lower rigidity of the flexible armors renders them incapable of providing sufficient resistance against impact attacks. To address the inherent conflict between flexibility and impact resistance in traditional armors, here, a composite is developed by hybridizing a shear-stiffening gel as the matrix and chemically-strengthened ultrathin glass sheets (CSGS) as the reinforcement. The resulting laminate, termed PCCL, exhibits both high flexibility and high impact resistance. Specifically, at low strain rates, the high ductility of the gel combined with the high flexural strength of the CSGS enables the PCCL to undergo considerable deformation; at high strain rates, on the other hand, the shear stiffening behavior of the gel matrix endows the PCCL with excellent impact resistance manifested by its high performance in energy absorption and high rigidity. With the combination of high flexibility and high impact resistance, the PCCL is demonstrated to be an ideal armor for protecting curved vulnerable objects from impact attacks.

Structural analysis and optoelectronic applications of 2-aminopyrimidine with pimelic acid crystal

This study investigates the reaction between 2-aminopyrimidine and pimelic acid, resulting in the formation of a novel crystal. The crystals were obtained through slow evaporation process. These crystals underwent PXRD testing to establish their crystalline properties. The values of the unit cell parameters are confirmed through SXRD analysis. The FTIR technique is applied to detect different functional groups present in the title crystals. The UV-Visible spectrum is recorded to find the band gap energy. From the photoluminescence spectrum the emission is observed at 353nm. The mechanical strength of the material against deformation is studied using Vickers micro hardness tester and the material is stated as soft material. The dielectric behaviour of the crystal is studied using LCRZ meter.

Towards Simpler Modelling Expressions for the Mechanical Characterization of Soft Materials

Aims: The aim of this paper is to develop a new, simple equation for deep spherical indentations. Background: The Hertzian theory is the most widely applied mathematical tool when testing soft materials because it provides an elementary equation that can be used to fit force-indentation data and determine the mechanical properties of the sample (i.e., its Young’s modulus). However, the Hertz equation is only valid for parabolic or spherical indenters at low indentation depths. For large indentation depths, Sneddon’s extension of the Hertzian theory offers accurate force-indentation equations, while alternative approaches have also been developed. Despite ongoing mathematical efforts to derive new accurate equations for deep spherical indentations, the Hertz equation is still commonly used in most cases due to its simplicity in data processing. Objective: The main objective of this paper is to simplify the data processing for deep spherical indentations, primarily by providing an accurate equation that can be easily fitted to force-indentation data, similar to the Hertzian equation Methods: A simple power-law equation is derived by considering the equal work done by the indenter using the actual equation. Results: The mentioned power-law equation was tested on simulated force-indentation data created using both spherical and sphero-conical indenters. Furthermore, it was applied to experimental force-indentation data obtained from agarose gels, demonstrating remarkable accuracy. Conclusion: A new elementary power-law equation for accurately determining Young’s modulus in deep spherical indentation has been derived.