Analytical Techniques in Molecular Simulation and Its Application in Energetic Materials.

Efficient design on the molecular and crystal levels is an urgent need to accelerate the development of energetic materials (EMs), and the performance analysis of microstructures is the most important thing in the research and design of EMs. Although molecular simulation methods are widely used in various research fields, there are few comprehensive reviews on analytical techniques. It is urgent to understand the basic principles of various analytical methods in the research of EMs.

Mannose/stearyl chloride doubly functionalized polyethylenimine as a nucleic acid vaccine carrier to promote macrophage uptake.

Transmembrane transport remains a significant challenge for nucleic acid vaccine vectors. Promoting the ability of immune cells, such as macrophages, to capture foreign stimuli is also an effective approach to improving cross-presentation. In addition, polyethyleneimine (PEI) has gained attention in the field of nucleic acid vaccine carriers due to its excellent gene transfection efficiency and unique proton buffering effect.

High-Stability Composite Solid Polymer Electrolyte Composed of PAEPU/PP Nonwoven Fabric for Lithium-Ion Batteries.

Solid polymer electrolytes have attracted considerable attention, owing to their flexibility and safety. At present, poly(ethylene oxide) is the most widely studied polymer electrolyte matrix. It exhibits higher safety than the polyolefin diaphragm used in traditional lithium-ion batteries.

Effects of Temperature on Novel Molecular Perovskite Energetic Material (CHN)[NH(ClO)]: A Molecular Dynamics Simulation.

Molecular dynamics (MD) simulations were performed on the energetic molecular perovskite (CHN)[NH(ClO)], with excellent detonation properties, thermal stability, and high specific impulse, which is a potential replacement for AP as the next generation propellants. The cohesive energy density, binding energy, pair correlation function, maximum bond length () of the N-H trigger bond, and mechanical properties of the (CHN)[NH(ClO)] were reported. The calculated cohesive energy density and binding energy decrease with increasing temperature, indicating a gradual decrease in the thermal stability with temperature.

Interaction, Insensitivity and Thermal Conductivity of CL-20/TNT-Based Polymer-Bonded Explosives through Molecular Dynamics Simulation.

Binders mixed with explosives to form polymer-bonded explosives (PBXs) can reduce the sensitivity of the base explosive by improving interfacial interactions. The interface formed between the binder and matrix explosive also affects the thermal conductivity. Low thermal conductivity may result in localized heat concentration inside the PBXs, causing the detonation of the explosive.

Polyaspartate Polyurea-Based Solid Polymer Electrolyte with High Ionic Conductivity for the All-Solid-State Lithium-Ion Battery.

The existing in situ preparation methods of solid polymer electrolytes (SPEs) often require the use of a solvent, which would lead to a complicated process and potential safety hazards. Therefore, it is urgent to develop a solvent-free in situ method to produce SPEs with good processability and excellent compatibility. Herein, a series of polyaspartate polyurea-based SPEs (PAEPU-based SPEs) with abundant (PO)(EO)(PO) segments and cross-linked structures were developed by systematically regulating the molar ratios of isophorone diisocyanate (IPDI) and isophorone diisocyanate trimer (tri-IPDI) in the polymer backbone and LiTFSI concentrations via an in situ polymerization method, which gave rise to good interfacial compatibility.

Microfluidic-Assisted Self-Assembly of 2D Nanosheets toward in situ Generation of Robust Nanofiber Film.

Methods allow the enhancement of nanofibers via self-assembly are potentially important for new disciplines with many advantages, including multi-anchor interaction, intrinsic mechanical properties and versatility. Herein, a microfluidic-assisted self-assembly process to construct hydroxyl functionalized boron nitride nanosheets (OH-BNNS)/graphene oxide (GO)/thermoplastic polyurethane (TPU) composite nanofiber film, in which stable and precisely controlled self-assembly is fulfilled by the confined ultra-small-volume chip is demonstrated. Multiple fine structural analyses alongside with the density-functional theory (DFT) calculations are implemented to confirm the synergistic effect of noncovalent interactions (hydrogen bonding interaction, π - π stacking interaction, and van der Waals attraction) plays a critical role in the robust micro-structure and a massive 700% enhancement of mechanical strength via adding only 0.

Preparation and Evaluation of Polyacrylate Microgels and Their Adjuvant Activities Using Ovalbumin as a Model Antigen.

As vaccine adjuvants, polyacrylate materials can induce a specific immune response in the body and have been widely studied in recent years due to their advantages, such as their safety, effectiveness, and low required dosage. In this study, a series of polyacrylates with hydrophobic physical crosslinking and chemical crosslinking were prepared using precipitation polymerization, and their structures were characterized by nuclear magnetic resonance spectroscopy and Fourier-transform infrared spectroscopy. The optimal reaction conditions were determined according to the effect of reaction time, azodiisobutyronitrile, Span 60, allyl pentaerythritol, and octadecyl methacrylate (OMA) contents on the viscosity of the polyacrylate microgel, combined with the effects of allyl pentaerythritol and OMA contents on the subcutaneous immune safety of the polyacrylate microgel in BALB/c mice.

First-principles study on the mechanical and electronic properties of energetic molecular perovskites AM(ClO) (A = CHN , CHN , CHNO; M = Na, K).

Density functional theory (DFT) simulations were conducted to study the crystal structures, and mechanical and electronic properties of a series of new energetic molecular perovskites, including (CHN)[Na(ClO)], (CHN)[K(ClO)], (CHN)[Na(ClO)] and (CHNO)[K(ClO)], abbreviated as DAP-1, DAP-2, PAP-1, and DAP-O2, respectively. By calculating the elastic constants, moduli (Young's modulus , bulk modulus , and shear modulus ), Poisson ratio and Pugh's ratio /, we found that the four energetic molecular perovskites not only possessed good mechanical stability but excellent mechanical flexibility and ductility. In addition, DFT calculations were used to investigate the electronic properties of all of the perovskite compounds.

Anisotropic Impact Sensitivity of Metal-Free Molecular Perovskite High-Energetic Material (CHN)(NHNH)(ClO) by First-Principles Study.

Density functional theory simulations were carried out to investigate energetic molecular perovskite (CHN)(NHNH)(ClO) which was a new type energetic material promising for future application. The electronic properties, surface energy, and hydrogen bonding of (100), (010), (011), (101), (111) surfaces were studied, and the anisotropic impact sensitivity of these surfaces were reported. By comparing the values of the band gaps for different surface structures, we found that the (100) surface has the lowest sensitivity, while the (101) surface was considered to be much more sensitive than the others.

Fabrication and characterization of structurally stable pH-responsive polymeric vesicles by polymerization-induced self-assembly.

Smart polymeric vesicles with both tertiary amine and epoxy functional groups were fabricated for the first time a reversible addition-fragmentation chain transfer dispersion polymerization approach, using (2-(diisopropylamino)ethyl methacrylate (DIPEMA) and glycidyl methacrylate (GlyMA) in an ethanol-water mixture. Monitoring of the polymerization revealed the low molecular weight distributions and the intermediate structures of spheres and worms, indicating an evolution in particle morphology. A phase diagram was constructed for reproducible fabrication of the vesicles, and copolymer composition was found to be more related to particle morphology.

Ion Transport in the EMITFSI/PVDF System at Different Temperatures: A Molecular Dynamics Simulation.

We used all-atom molecular dynamics simulations to study the ion transport in the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/poly(vinylidene fluoride) (EMITFSI/PVDF) system with 40.05 wt % EMITFSI at different temperatures. The glass-transition temperature ( = 204 K) of this system shows a good agreement with the experimental value (200 K).

Long-term corrosion protection of styrene acrylic coatings enhanced by fluorine and nitrogen co-doped graphene oxide.

Graphene materials are widely used as a physical barrier when applying anticorrosion polymer coatings due to their large surface area and layered structure. However, the electrical conductivity of intrinsic graphene can accelerate galvanic corrosion and shorten the protection period. In this work, fluorine and nitrogen co-doped graphene oxide (FNGO) was synthesized by a hydrothermal process and acted as an anticorrosion filler in waterborne styrene acrylic coatings.

Molecular Dynamics Simulations for Effects of Fluoropolymer Binder Content in CL-20/TNT Based Polymer-Bonded Explosives.

In order to better understand the role of binder content, molecular dynamics (MD) simulations were performed to study the interfacial interactions, sensitivity and mechanical properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/TNT) based polymer-bonded explosives (PBXs) with fluorine rubber F. The binding energy between CL-20/TNT co-crystal (1 0 0) surface and F, pair correlation function, the maximum bond length of the N-NO trigger bond, and the mechanical properties of the PBXs were reported. From the calculated binding energy, it was found that binding energy increases with increasing F content.

Preparation of polyacrylate/nanoemulsion composites and their adjuvant activity with OVA as the model antigen.

A series of polyacrylate/nanoemulsion composites were prepared to form a new kind of nanoemulsion, their particle sizes and polydispersity indices were measured. The particle sizes of the polyacrylate/nanoemulsion composites are consistent with nanoemulsions used in the system. In addition, an ELISA-specific antigen-antibody binding method was used for physical adsorption experiments on ovalbumin.

High-Performance Poly(vinylidene difluoride)/Dopamine Core/Shell Piezoelectric Nanofiber and Its Application for Biomedical Sensors.

Fabrication of soft piezoelectric nanomaterials is essential for the development of wearable and implantable biomedical devices. However, a big challenge in this soft functional material development is to achieve a high piezoelectric property with long-term stability in a biological environment. Here, a one-step strategy for fabricating core/shell poly(vinylidene difluoride) (PVDF)/dopamine (DA) nanofibers (NFs) with a very high β-phase content and self-aligned polarization is reported.

A high-density genetic map of Schima superba based on its chromosomal characteristics.

Background: Schima superba (Theaceae) is a popular woody tree in China. The obscure chromosomal characters of this species are a limitation in the development of high-density genetic linkage maps, which are valuable resources for molecular breeding and functional genomics.

Results: We determined the chromosome number and the karyotype of S.

Molecular dynamic simulations on the structures and properties of epsilon-CL-20(0 0 1)/F 2314 PBX.

Molecular dynamical (MD) simulations with the COMPASS force field were employed to investigate the influences of temperature (T), the concentration of F(2314) binder (W%), and crystal defects on the mechanical properties, binding energy (E(bind)), and detonation properties of epsilon-CL-20(001)/F(2314) PBX (polymer bonded explosives). T was found to have some influences on the mechanical properties, and the PBX at 298 K was considered with better mechanical properties. By radial distribution function g(r) analysis the three types of hydrogen bonds, H.

Molecular dynamics simulations of AP/HMX composite with a modified force field.

An all-atom force field for ammonium perchlorate (AP) is developed with the framework of pcff force field. The structural parameters of AP obtained with the modified force field are in good agreement with experimental values. Molecular dynamics (MD) simulations have been performed to investigate AP/HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) composite at different temperatures.

Molecular dynamics simulations of RDX and RDX-based plastic-bonded explosives.

Molecular dynamics simulations have been performed to investigate well-known energetic material cyclotrimethylene trinitramine (RDX) crystal and RDX-based plastic-bonded explosives (PBXs) with four typical fluorine-polymers, polyvinylidenedifluoride (PVDF), polychlorotri-fluoroethylene (PCTFE), fluorine rubber (F(2311)), and fluorine resin (F(2314)). The elastic coefficients, mechanical properties, binding energies, and detonation performances are obtained for the RDX crystal and RDX-based PBXs. The results indicate that the mechanical properties of RDX can be effectively improved by blending with a small amount of fluorine polymers and the overall effect of fluorine polymers on the mechanical properties of the PBXs along three crystalline surfaces is (001)>(010) approximately (100) and PVDF is regarded to best improve the mechanical properties of the PBXs on three surfaces.

Theoretical studies of solid bicyclo-HMX: effects of hydrostatic pressure and temperature.

On the basis of density functional theory (DFT) and molecular dynamics (MD), the structural, electronic, and mechanical properties of the energetic material bicyclo-HMX have been studied. The crystal structure optimized by the LDA/CA-PZ method compares well with the experimental data. Band structure and density of states calculations indicate that bicyclo-HMX is an insulator with the band gap of ca.

Molecular dynamics study of the structure and performance of simple and double bases propellants.

To investigate the structure and performance of simple and double bases propellants, the nitrocellulose (NC), nitroglycerin (NG), and double mixed system (NC+NG) have been simulated by using the molecular dynamics (MD) method with the COMPASS force field. The interactions between NC and NG have been analyzed by means of pair correlation functions. The mechanical properties of the three model systems, i.

Molecular dynamics simulations of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin-based polymer-bonded explosives.

Molecular dynamics has been applied to investigate the low-sensitivity explosive TNAD (trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin)-based polymer-bonded explosives (PBXs) with four typical fluorine polymers, PVDF (polyvinylidenedifluoride), PCTFE (polychlorotrifluoroethylene), F(2311) (fluorine rubber), and F(2314) (fluorine resin). The elastic constants, mechanical properties (tensile modulus, bulk modulus, shear modulus, and Poission ratio), binding energies, and detonation performances are first reported for the TNAD-based PBXs. The results show that the mechanical properties of TNAD can be effectively improved by the addition of small amounts of fluorine polymers, and the overall effect of fluorine polymers on the mechanical properties of the PBXs along three crystalline surfaces is (001) > (010) > (100).

Ab initio and molecular dynamics studies of crystalline TNAD (trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin).

The structural and electronic properties of the energetic crystal TNAD (trans-1,4,5,8-tetranitro-1,4,5,8- tetraazadecalin) have been studied using plane-wave ab initio calculations based on the density function theory method with the ultrasoft pseudopotentials. It is found that the predicted crystal structure is in good agreement with experimental data and there are strong inter- and intramolecular interactions in bulk TNAD. Band structure calculations indicate that TNAD is an insulator with the band gap of ca.

Comparative first-principles study of structural and optical properties of alkali metal azides.

A comparative first-principles study of the structural and optical properties of the alkali metal azides has been performed with density functional theory within the generalized gradient approximation. The crystal structures of the alkali azides compare well with experimental data. Their ionic character is manifested by the closeness of their internitrogen distances to the calculated N-N bond length for the free azide ion.