Chemically Responsive Hydrogel Deformation Mechanics: A Review

A hydrogel is a polymeric three-dimensional network structure. The applications of this material type are diversified over a broad range of fields. Their soft nature and similarity to natural tissue allows for their use in tissue engineering, medical devices, agriculture, and industrial health products. However, as the demand for such materials increases, the need to understand the material mechanics is paramount across all fields. As a result, many attempts to numerically model the swelling and drying of chemically responsive hydrogels have been published. Material characterization of the mechanical properties of a gel bead under osmotic loading is difficult. As a result, much of the literature has implemented variants of swelling theories. Therefore, this article focuses on reviewing the current literature and outlining the numerical models of swelling hydrogels as a result of exposure to chemical stimuli. Furthermore, the experimental techniques attempting to quantify bulk gel mechanics are summarized. Finally, an overview on the mechanisms governing the formation of geometric surface instabilities during transient swelling of soft materials is provided.

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Characterization of Polycaprolactone Nanohydroxyapatite Composites with Tunable Degradability Suitable for Indirect Printing

Polymers ◽

10.3390/polym13020295 ◽

2021 ◽

Vol 13 (2) ◽

pp. 295

Author(s):

Stephanie E. Doyle ◽

Lauren Henry ◽

Ellen McGennisken ◽

Carmine Onofrillo ◽

Claudia Di Bella ◽

...

Keyword(s):

Molecular Weight ◽

Large Scale ◽

Three Dimensional ◽

Cell Number ◽

Compressive Modulus ◽

Degradation Rates ◽

Scaffold Materials ◽

Natural Tissue ◽

Complete Regeneration

Degradable bone implants are designed to foster the complete regeneration of natural tissue after large-scale loss trauma. Polycaprolactone (PCL) and hydroxyapatite (HA) composites are promising scaffold materials with superior mechanical and osteoinductive properties compared to the single materials. However, producing three-dimensional (3D) structures with high HA content as well as tuneable degradability remains a challenge. To address this issue and create homogeneously distributed PCL-nanoHA (nHA) scaffolds with tuneable degradation rates through both PCL molecular weight and nHA concentration, we conducted a detailed characterisation and comparison of a range of PCL-nHA composites across three molecular weight PCLs (14, 45, and 80 kDa) and with nHA content up to 30% w/w. In general, the addition of nHA results in an increase of viscosity for the PCL-nHA composites but has little effect on their compressive modulus. Importantly, we observe that the addition of nHA increases the rate of degradation compared to PCL alone. We show that the 45 and 80 kDa PCL-nHA groups can be fabricated via indirect 3D printing and have homogenously distributed nHA even after fabrication. Finally, the cytocompatibility of the composite materials is evaluated for the 45 and 80 kDa groups, with the results showing no significant change in cell number compared to the control. In conclusion, our analyses unveil several features that are crucial for processing the composite material into a tissue engineered implant.

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Synthesis and structural characterization of hexa-μ2-chlorido-μ4-oxido-tetrakis{[4-(phenylethynyl)pyridine-κN]copper(II)} dichloromethane monosolvate

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989020015935 ◽

2021 ◽

Vol 77 (1) ◽

pp. 42-46

Author(s):

Rayya A. Al Balushi ◽

Muhammad S. Khan ◽

Md. Serajul Haque Faizi ◽

Ashanul Haque ◽

Kieran Molloy ◽

...

Keyword(s):

Molecular Structure ◽

Crystal Structure ◽

Structural Characterization ◽

Title Compound ◽

Three Dimensional ◽

Hirshfeld Surface ◽

The Core ◽

Dimensional Network ◽

Packing Arrangement

In the crystal structure of the title compound, [Cu4Cl6O(C13H9N)4]·CH2Cl2, the core molecular structure consists of a Cu4 tetrahedron with a central interstitial O atom. Each edge of the Cu4 tetrahedron is bridged by a chlorido ligand. Each copper(II) cation is coordinated to the central O atom, two chlorido ligands and one N atom of the 4-phenylethynylpyridine ligand. In the crystal, the molecules are linked by intermolecular C—H...Cl interactions. Furthermore, C—H...π and π–π interactions also connect the molecules, forming a three-dimensional network. Hirshfeld surface analysis indicates that the most important contributions for the packing arrangement are from H...H and C...H/H...C interactions.

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Synthesis and Characterization of [2-CH3CH2C6H4NH3]6P6O18⋅4H2O

ISRN Materials Science ◽

10.5402/2011/457924 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Houda Marouani ◽

Salem Slayyem Al-Deyab ◽

Mohamed Rzaigui

Keyword(s):

Hydrogen Bonds ◽

Electrostatic Interactions ◽

Three Dimensional ◽

Spectroscopic Studies ◽

Monoclinic System ◽

Dimensional Network ◽

Cell Dimensions ◽

Unit Cell Dimensions ◽

Ir Spectroscopic

Single crystals of [2-CH3CH2C6H4NH3]6P6O18⋅4H2O are synthesized in aqueous solution by the interaction of cyclohexaphosphoric acid and 2-ethylaniline. This compound crystallizes in the monoclinic system with P21/c space group the unit cell dimensions are: a=16.220(4) Å, b=10.220(5) Å, c=20.328(4) Å, β=113.24(3)∘, Z=2, and V=3096.5(18) Å3. The atomic arrangement can be described by layers formed by cyclohexaphosphate anions P6O186− and water molecules connected by hydrogen bonds O–H⋯O. These inorganic layers are developed around bc planes at x=1/2 and are interconnected by the H-bonds created by ammonium groups of organic cations. All the hydrogen bonds, the van der Waals contacts and electrostatic interactions between the different entities give rise to a three-dimensional network in the structure and add stability to this compound. The thermal behaviour and the IR spectroscopic studies of this new cyclohexaphosphate are discussed.

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Three-Dimensional Strain-Based Model for the Severity Characterization of Dented Pipelines

Journal of Nondestructive Evaluation Diagnostics and Prognostics of Engineering Systems ◽

10.1115/1.4040039 ◽

2018 ◽

Vol 1 (3) ◽

Author(s):

Chike Okoloekwe ◽

Muntaseer Kainat ◽

Doug Langer ◽

Sherif Hassanien ◽

J.J. Roger Cheng ◽

...

Keyword(s):

Oil And Gas ◽

Numerical Models ◽

Three Dimensional ◽

Strain Analysis ◽

Computation Time ◽

Order Continuity ◽

Element Analysis ◽

The Mathematical Model ◽

Derivatives Of

Oil and gas pipelines traverse long distances and are often subjected to mechanical forces that result in permanent distortion of its geometric cross section in the form of dents. In order to prioritize the repair of dents in pipelines, dents need to be ranked in order of severity. Numerical modeling via finite element analysis (FEA) to rank the dents based on the accumulated localized strain is one approach that is considered to be computationally demanding. In order to reduce the computation time with minimal effect to the completeness of the strain analysis, an approach to the analytical evaluation of strains in dented pipes based on the geometry of the deformed pipe is presented in this study. This procedure employs the use of B-spline functions, which are equipped with second-order continuity to generate displacement functions, which define the surface of the dent. The strains associated with the deformation can be determined by evaluating the derivatives of the displacement functions. The proposed technique will allow pipeline operators to rapidly determine the severity of a dent with flexibility in the choice of strain measure. The strain distribution predicted using the mathematical model proposed is benchmarked against the strains predicted by nonlinear FEA. A good correlation is observed in the strain contours predicted by the analytical and numerical models in terms of magnitude and location. A direct implication of the observed agreement is the possibility of performing concise strain analysis on dented pipes with algorithms relatively easy to implement and not as computationally demanding as FEA.

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Synthesis and Structural Characterization of the Mixed Ligand Complex [Cu(Hml)2(Phen)] · 2 H2O (H2ml = 2-Methyllactic Acid)

Zeitschrift für Naturforschung B ◽

10.1515/znb-2003-0122 ◽

2003 ◽

Vol 58 (1) ◽

pp. 151-154 ◽

Cited By ~ 7

Author(s):

Rosa Carballo ◽

Berta Covelo ◽

Ezequiel M. Vázquez-Lópeza ◽

Alfonso Castiñeiras ◽

Juan Niclós

Keyword(s):

Magnetic Measurements ◽

Mixed Ligand Complex ◽

Three Dimensional ◽

Mixed Ligand ◽

Water Molecules ◽

Ligand Complex ◽

X Ray ◽

Dimensional Network ◽

Distorted Octahedral

Abstract A new mixed-ligand complex of copper(II) with 1,10-phenanthroline and 2-methyllactate was prepared. [Cu(HmL)2(phen)] ·2H2O (where HmL = monodeprotonated 2-methyllactic acid) was characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements at room temperature, thermogravimetric analysis and X-ray diffractometry. The copper atom is in a tetragonally distorted octahedral environment and the 2-methyllactato ligand is bidentately chelating. The presence of lattice water molecules mediates the formation of a three-dimensional network.

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Effect of the drying on morphology and texture of aerogels and zirconia cryogels

MRS Advances ◽

10.1557/adv.2019.450 ◽

2019 ◽

Vol 4 (64) ◽

pp. 3513-3521

Author(s):

Tzipatly A. Esquivel-Castro ◽

Antonia Martínez-Luévanos ◽

Luis Alfonso García-Cerda ◽

Juan C. Contreras-Esquivel ◽

Pascual Bartolo Pérez ◽

...

Keyword(s):

Drug Delivery ◽

Cetyltrimethylammonium Bromide ◽

Sol Gel ◽

Three Dimensional ◽

Supercritical Drying ◽

Sem Images ◽

Texture Properties ◽

Dimensional Network ◽

Zirconia Aerogel

ABSTRACTDue to their excellent properties, aerogel has attracted the attention of the scientific community to use it in the biomedical area as a drug delivery system. This work reports on the synthesis and characterization of ZrO2 aerogels and cryogels obtained by the sol-gel method. The influence of different cetyltrimethylammonium bromide (CTAB) and the type of drying on structural, morphological and texture properties of ZrO2 aerogels and cryogels was investigated. SEM images reveal that a porous interconnected three-dimensional network was formed into aerogels due to supercritical drying. Zirconia aerogel sample has a specific surface area (SBET) larger than zirconia cryogels. Therefore, our results indicate that zirconia aerogel is an adequate material for applications in drug delivery systems.

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Synthesis and Characterization of the Manganese Borate α-MnB2O4

Zeitschrift für Naturforschung B ◽

10.1515/znb-2011-0903 ◽

2011 ◽

Vol 66 (9) ◽

pp. 882-888

Author(s):

Stephanie C. Neumair ◽

Lukas Perfler ◽

Hubert Huppertz

Keyword(s):

High Pressure ◽

Three Dimensional ◽

Lattice Parameters ◽

Synthesis And Characterization ◽

Manganese Ions ◽

Space Group ◽

Dimensional Network ◽

Oxygen Atoms

The high-pressure manganese borate α-MnB2O4 was synthesized under high-pressure/hightemperature conditions of 6.5 GPa and 1100 ◦C in a modified Walker-type multianvil apparatus. The monoclinic compound is isotypic to α-FeB2O4, CaAl2O4-II, CaGa2O4, andβ -SrGa2O4 crystallizing with eight formula units in the space group P21/c (Z = 8) with the lattice parameters a = 712.1(2), b = 747.1(2), c = 878.8(2) pm, β = 94.1(1)◦, V = 0.466(1) nm3, R1 = 0.0326, and wR2 = 0.0652 (all data). The compound is built up from layers of “sechser” rings of corner-sharing BO4 tetrahedra that are interconnected to a three-dimensional network. The manganese ions are coordinated by seven oxygen atoms and situated in channels along the a axis.

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Preparation and Characterization of 2-Phenoxyethyl(thiophen-2-yl)tellane (C4H3S)TeCH2CH2OC6H5

Zeitschrift für Naturforschung B ◽

10.1515/znb-2006-0112 ◽

2006 ◽

Vol 61 (1) ◽

pp. 61-64

Author(s):

Ludmila Vigo ◽

Raija Oilunkaniemi ◽

Risto S. Laitinen

Keyword(s):

Three Dimensional ◽

Monoclinic Crystal ◽

X Ray ◽

Compound C ◽

Dimensional Network ◽

Cell Dimensions ◽

Weak Hydrogen Bonds ◽

Intermolecular Contacts ◽

Unit Cell Dimensions

The synthesis and structure of (C4H3S)TeCH2CH2OC6H5 (1) (C4H3S = thiophen-2-yl) are reported and compared to those of the analogous selenium compound (C4H3S)SeCH2CH2OC6H5 previously synthesized by our group. The compound was characterized by 1H, 13C{1H}-, and 125Te- NMR spectroscopy as well as by X-ray single crystal crystallography. 1 crystallizes in the monoclinic crystal system, space group P21, with Z = 2, and unit cell dimensions a = 10.618(2) Å , b = 5.357(1) Å , c = 10.684(2) Å , β = 96.57(3)°. The lattice is composed of discrete molecules that are joined together by weak hydrogen bonds into a three-dimensional network. The thiophen-2-yl ring is disordered and shows two alternative orientations with the site occupation factors of 0.70(1) and 0.30(1). All bond parameters are quite normal. The comparison of the lattices in 1 and in its selenium anologue shows that while the closest intermolecular contacts are similar, the packing of the molecules is different.

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Mechanical Characterization of Timber-to-Timber Composite (TTC) Joints with Self-Tapping Screws in a Standard Push-Out Setup

Applied Sciences ◽

10.3390/app10186534 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6534

Author(s):

Chiara Bedon ◽

Martina Sciomenta ◽

Massimo Fragiacomo

Keyword(s):

Mechanical Characterization ◽

Numerical Models ◽

Three Dimensional ◽

Analytical Models ◽

Small Scale ◽

Load Bearing ◽

Timber Constructions ◽

Technical Interest ◽

Push Out

Self-tapping screws (STSs) can be efficiently used in various fastening solutions for timber constructions and are notoriously able to offer high stiffness and load-carrying capacity, compared to other timber-to-timber composite (TTC) joint typologies. The geometrical and mechanical characterization of TTC joints, however, is often hard and uncertain, due to a combination of various influencing parameters and mechanical aspects. Among others, the effects of friction phenomena between the system components and their reciprocal interaction under the imposed design loads can remarkably influence the final estimates on structural capacity, in the same way of possible variations in the boundary conditions. The use of Finite Element (FE) numerical models is well-known to represent a robust tool and a valid alternative to costly and time consuming experiments and allows one to further explore the selected load-bearing components at a more refined level. Based on previous research efforts, this paper presents an extended FE investigation based on full three-dimensional (3D) brick models and surface-based cohesive zone modelling (CZM) techniques. The attention is focused on the mechanical characterization of small-scale TTC specimens with inclined STSs having variable configurations, under a standard push-out (PO) setup. Based on experimental data and analytical models of literature, an extended parametric investigation is presented and correlation formulae are proposed for the analysis of maximum resistance and stiffness variations. The attention is then focused on the load-bearing role of the steel screws, as an active component of TTC joints, based on the analysis of sustained resultant force contributions. The sensitivity of PO numerical estimates to few key input parameters of technical interest, including boundaries, friction and basic damage parameters, is thus discussed in the paper.

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Synthesis and structural characterization of two coordination polymers constructed by bis(4-(1H-imidazol-1-yl)phenyl)methanone and 5-(tert-butyl)isophthalate ligands

Zeitschrift für Naturforschung B ◽

10.1515/znb-2018-0197 ◽

2019 ◽

Vol 74 (3) ◽

pp. 261-265 ◽

Cited By ~ 4

Author(s):

Gao-Feng Wang ◽

Shu-Wen Sun ◽

Wei-Bing Wang ◽

Hong Sun ◽

Shao-Fei Song

Keyword(s):

Single Crystal ◽

Coordination Polymers ◽

Weak Interactions ◽

Three Dimensional ◽

X Ray Diffraction ◽

X Ray ◽

Dimensional Network ◽

Elemental Analyses ◽

Solvothermal Methods

AbstractTwo coordination polymers, {[Co(bipmo)(tbip)]·3H2O}n (1) and {[Cd(bipmo)(tbip)]·3H2O}n (2) (bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2tbip=5-tert-butylisophthalic acid), were synthesized by solvothermal methods and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction data indicate that the solid state structures of 1 and 2 consist of metal-aromatic carboxylate layers, which are pillared by weak interactions to generate a three-dimensional network. The topological structures of 1 and 2 are uninodal nets based on 3-connected nodes with the Schläfli symbol of {63}.

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