scholarly journals Modeling of Structure-Property Relationships of Polymerizable Surfactants with Antimicrobial Activity

2018 ◽  
Vol 8 (10) ◽  
pp. 1972 ◽  
Author(s):  
Giorgio De Luca ◽  
Roberta Amuso ◽  
Alberto Figoli ◽  
Raffaella Mancuso ◽  
Lucio Lucadamo ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Molecular Structures ◽  
Maximum Length ◽  
Aliphatic Chain ◽  
Structure Property ◽  
Net Charge ◽  
Structure Property Relationships ◽  
Electrostatic Charges ◽  
Partial Charges ◽  
The Relationship

Polymerizable quaternary ammonium salts (PQASs) were synthesized in a previous work and some of them were used as surfactants in the antimicrobial coating of commercial membranes. Herein, the electrostatic charges, maximum length, and aspect ratio of these antibacterial surfactants were calculated with the aim of investigating the relationship between the properties, recognized to control the biocidal activity of these molecules, and the molecular structures. The effect of the water molecules was considered through a quantum and molecular mechanics approach. The correlation between the number of carbons in the main aliphatic chain of PQAS and the above properties was investigated, by finding that the net charge on the ammonium group does not increase as the number of carbons in the aliphatic chain increase. Thus, although this number influences the antibacterial activity of the surfactants, this influence is not correlated with an increase of the ammonium positive charge. Unlike the partial charges, a different trend was obtained for the surfactants’ maximum length and aspect ratio in agreement with the experimental behavior. As this modeling does not use empirical or adjustable parameters, it can assist the synthetic plan of new structures for surface functionalization, in order to improve the biofouling resistance of the membranes.

Development of Materials Informatics Tools and Infrastructure to Enable High Throughput Materials Design

2012 ◽  
Vol 1425 ◽  
Author(s):  
Michael P. Krein ◽  
Bharath Natarajan ◽  
Linda S. Schadler ◽  
L. C. Brinson ◽  
Hua Deng ◽  
...  
Keyword(s):  
A Priori ◽  
Molecular Structures ◽  
Work Of Adhesion ◽  
Materials Informatics ◽  
Structure Property ◽  
Surface Tensions ◽  
Virtual Experiments ◽  
Structure Property Relationships ◽  
Quantitative Structure Property Relationships ◽  
Informatics Tools

ABSTRACTPolymer nanocomposites (PNC) are complex material systems in which the dominant length scales converge. Our approach to understanding nanocomposite tradespace uses Materials Quantitative Structure-Property Relationships (MQSPRs) to relate molecular structures to the polar and dispersive components of corresponding surface tensions. If the polar and dispersive components of surface tensions in the nanofiller and polymer could be determined a priori, then the propensity to aggregate and the change in polymer mobility near the particle could be predicted. Derived energetic parameters such as work of adhesion, work of spreading and the equilibrium wetting angle may then used as input to continuum mechanics approaches that have been shown able to predict the thermomechanical response of nanocomposites and that have been validated by experiment. The informatics approach developed in this work thus enables future in silico nanocomposite design by enabling virtual experiments to be performed on proposed nanocomposite compositions prior to fabrication and testing.

scholarly journals Structure-Property Relationships in Benzofurazan Derivatives: A Combined Experimental and DFT/TD-DFT Investigation

2021 ◽  
Author(s):  
Hanen Raissi ◽  
Imen Chérif ◽  
Hajer Ayachi ◽  
Ayoub Haj Said ◽  
Fredj Hassen ◽  
...  
Keyword(s):  
Energy Levels ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Structure Property ◽  
Electrophilicity Index ◽  
Cyclic Amines ◽  
Structure Property Relationships ◽  
Physico Chemical ◽  
Homo And Lumo ◽  
The Relationship

In this work we seek to understand and to quantify the reactivity of benzofurazan derivatives toward secondary cyclic amines, like pyrrolidine, piperidine and morpholine, acting as nucleophile groups in SNAr reactions. For this aim, physico-chemical and structural descriptors were determined experimentally and theoretically using the DFT/B3LYP/6-31+ g (d,p) methodology. Thus, different 4-X-7-nitrobenzofurazans (X = OCH3, OC6H5 and Cl) and products corresponding to the electrophilic aromatic substitution by pyrrolidine, piperidine and morpholine, were investigated. Particularly, the HOMO and LUMO energy levels of the studied compounds, determined by Cyclic Voltammetry (CV) and DFT calculations, were used to evaluate the electrophilicity index (ω). The latter was exploited, according to Parr’s approach, to develop a relationship which rationalizes the kinetic data previously reported for the reactions of the 4-X-7-nitrobenzofurazans with nucleophiles cited above. Moreover, the Parr’s electrophilicity index (ω) of these benzofurazans determined in this work were combined with their electrophilicity parameters (E), reported in preceding papers, was found to predict the unknown electrophilicity parameters E of 4-piperidino, 4-morpholino and 4-pyrrolidino-7-nitrobenzofurazan. In addition, the relationship between the Parr’s electrophilicity index (ω) and Hammett constants σ, has been used as a good model to predict the electronic effect of the nucleophile groups. Finally, we will subsequently compare the electrophilicity index (ω) and the electrophilicity parameters (E) of these series of 7-X-4-nitrobenzofurazans with the calculated dipole moment (μ) in order to elucidate general relationships between E, ω and μ.

scholarly journals New Insight into the Toughening Mechanisms of Seashell: From Arch Shape to Multilayer Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Quan Yuan ◽  
Botao Chen ◽  
Bin Chen ◽  
Zeyun Wang
Keyword(s):  
Aspect Ratio ◽  
Multilayer Structure ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Structure Property ◽  
Soft Layer ◽  
Structure Property Relationships ◽  
Straight Beam ◽  
Overlap Ratio ◽  
Arch Shape

A seashell is a closed three-dimensional curved surface formed by two symmetrical open shells. Three-point bending is performed on a pure aragonite straight beam (PASB) model and a multilayer structure curved beam (MSCB) model to elucidate the structure-property relationships of seashells. The integrity of the PASB is broken because of the introduction of a soft layer, but this drawback is compensated by the peculiar arch shape and the internal multilayer structure. The effective modulus, stiffness, and fracture energy of MSCB increase with an increase in volume fraction, aspect ratio of aragonite platelet, overlap ratio of hard layers, and ratio of the elastic modulus of the hard layer to the shear modulus of the soft layer. New design disciplines drawn from the MSCB model are peculiar arch shape, internal multilayer structure of larger volume fraction, and aspect ratio of hard layers and nanoscaled soft layers.

Petrofabric study using electron channeling patterns of quartzes and hematites in dual-phase banded iron formations

1995 ◽  
Vol 53 ◽  
pp. 388-389
Author(s):  
K. Y. Lee ◽  
B. W. Robertson
Keyword(s):  
Spatial Arrangement ◽  
Structure Property ◽  
Banded Iron Formations ◽  
Thin Sections ◽  
Electron Channeling ◽  
Structure Property Relationships ◽  
Structure Property Relationship ◽  
The Individual ◽  
The Relationship ◽  
Iron Formations

Research in deformation of rocks requires the understanding of structure-property relationship. The study of structure-property relationships requires knowledge of the crystallographic texture on a local scale. Electron Channeling in scanning microscope has been used to analyze textures of local features in a microstructure, misorientations between grains and the spatial arrangement of grains of individual crystallographic orientations can be determined. This information is critical for a mechanical understanding of microstructure evolution during the deformation of rocks. Petrofabric analysis using Electron Channeling Patterns can use normal geological thin sections and mounted sections, which allows relatively fast and easy interpretation and allows one to determine the relationship between a microstructural feature and the individual orientations of its grains. The most efficient and satisfactory way of accomplishing this task is by direct electronic detection and indexing of Kikuchi patterns, which requires modification of the microscope, at considerable cost. This study, however, has been undertaken using only an unmodified SEM with electron channeling capability.

scholarly journals Data driven discovery of conjugated polyelectrolytes for optoelectronic and photocatalytic applications

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yangyang Wan ◽  
Fernando Ramirez ◽  
Xu Zhang ◽  
Thuc-Quyen Nguyen ◽  
Guillermo C. Bazan ◽  
...  
Keyword(s):  
Machine Learning ◽  
Structural Features ◽  
Hole Transport ◽  
Molecular Structures ◽  
Trial And Error ◽  
First Principles Calculations ◽  
Structure Property ◽  
Conjugated Polyelectrolytes ◽  
Structure Property Relationships ◽  
Photocatalytic Applications

AbstractConjugated polyelectrolytes (CPEs), comprised of conjugated backbones and pendant ionic functionalities, are versatile organic materials with diverse applications. However, the myriad of possible molecular structures of CPEs render traditional, trial-and-error materials discovery strategy impractical. Here, we tackle this problem using a data-centric approach by incorporating machine learning with high-throughput first-principles calculations. We systematically examine how key materials properties depend on individual structural components of CPEs and from which the structure–property relationships are established. By means of machine learning, we uncover structural features crucial to the CPE properties, and these features are then used as descriptors in the machine learning to predict the properties of unknown CPEs. Lastly, we discover promising CPEs as hole transport materials in halide perovskite-based optoelectronic devices and as photocatalysts for water splitting. Our work could accelerate the discovery of CPEs for optoelectronic and photocatalytic applications.

Molecular origins of commercial laser dye functionality in azacoumarins and 2-quinolones: LD 425, LD 489 and LD 473

2011 ◽  
Vol 67 (6) ◽  
pp. 560-568 ◽  
Author(s):  
Xiaogang Liu ◽  
Jacqueline M. Cole ◽  
Paul G. Waddell ◽  
Tze-Chia Lin
Keyword(s):  
Charge Transfer ◽  
Molecular Design ◽  
Molecular Structures ◽  
Laser Dyes ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Resonance Theory ◽  
X Ray ◽  
Structure Property Relationships ◽  
Spectral Shifts

The molecular structures of three compounds, LD 425 (C13H14N2O3) (1), LD 489 (C15H15F3N2O2) (2) and LD 473 (C17H19F3N2O) (3), are determined by single-crystal X-ray diffraction (XRD) at 180 K. Azacoumarins (1) and (2) possess para-quinoidal bond-length patterns in their benzene rings due to intramolecular charge transfer (ICT) from these rings to the adjoining rings. In contrast, substitution of O with N within the coumarin heterocycle, to form a 2-quinolone, results in the suppression of this ICT effect. Instead, charge transfer within the heterocycle is shown to become more pronounced. Resonance theory is employed to discuss these bond pattern differences and characteristic spectral blue shifts in relation to their coumarin analogues. The application of this theory offers an intuitive understanding of the structure–property relationships in azacoumarins and 2-quinolones which is further supported by quantum chemical calculations. Such an understanding is important for recognizing ICT mechanisms in these compounds which can then be used to facilitate the molecular design of new laser dyes with the desired spectral shifts.

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