Lubricity from Entangled Polymer Networks on Hydrogels

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Angela A. Pitenis ◽  
Juan Manuel Urueña ◽  
Ryan M. Nixon ◽  
Tapomoy Bhattacharjee ◽  
Brandon A. Krick ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Polymer Network ◽  
Polymer Networks ◽  
Mesh Size ◽  
Solution Polymerization ◽  
Hydrogel Sample ◽  
Low Friction ◽  
Aqueous Environments ◽  
Surface Measurements ◽  
Entangled Polymer

Structural hydrogel materials are being considered and investigated for a wide variety of biotribological applications. Unfortunately, most of the mechanical strength and rigidity of these materials comes from high polymer concentrations and correspondingly low polymer mesh size, which results in high friction coefficients in aqueous environments. Recent measurements have revealed that soft, flexible, and large mesh size hydrogels can provide ultra low friction, but this comes at the expense of mechanical strength. In this paper, we have prepared a low friction structural hydrogel sample of polyhydroxyethylmethacrylate (pHEMA) by polymerizing an entangled polymer network on the surface through a solution polymerization route. The entangled polymer network was made entirely from uncrosslinked polyacrylamide (pAAm) that was polymerized from an aqueous solution and had integral entanglement with the pHEMA surface. Measurements revealed that these entangled polymer networks could extend up to ∼200 μm from the surface, and these entangled polymer networks can provide reductions in friction coefficient of almost two orders of magnitude (μ > 0.7 to μ < 0.01).

scholarly journals Multiply Interpenetrating Polymer Networks: Preparation, Mechanical Properties, and Applications

Gels ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 36 ◽  
Author(s):  
Panayiota A. Panteli ◽  
Costas S. Patrickios
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Polymer Network ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Interpenetrating Polymer Network ◽  
Low Friction ◽  
Friction Coefficients ◽  
Polymeric Component ◽  
Work Done

This review summarizes work done on triply, or higher, interpenetrating polymer network materials prepared in order to widen the properties of double polymer network hydrogels (DN), doubly interpenetrating polymer networks with enhanced mechanical properties. The review will show that introduction of a third, or fourth, polymeric component in the DNs would further enhance the mechanical properties of the resulting materials, but may also introduce other useful functionalities, including electrical conductivity, low-friction coefficients, and (bio)degradability.

Superlubricity in Gemini Hydrogels

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Angela A. Pitenis ◽  
Juan Manuel Urueña ◽  
Andrew C. Cooper ◽  
Thomas E. Angelini ◽  
W. Gregory Sawyer
Keyword(s):  
Friction Coefficient ◽  
Room Temperature ◽  
Mesh Size ◽  
Thermal Fluctuations ◽  
Low Friction ◽  
Contact Areas ◽  
Solvent Water ◽  
Aqueous Environments ◽  
Contact Pressures

Gemini hydrogels have repeatedly produced low friction under conditions generally not thought to be favorable to superlubricity: low sliding speeds, low contact pressures, macroscopic contact areas, and room temperature aqueous environments. A proposed explanation for this unique behavior is that thermal fluctuations at the interface are sufficient to separate the surfaces, with solvent (water) shearing in this region being the main source of dissipation. In this paper, we demonstrate that very soft and correspondingly large mesh size Gemini hydrogels show superlubricity with the lowest measured friction coefficient being μ = 0.0013 ± 0.0006.

scholarly journals Thermoset Polymer Matrix Structure and Properties: Coarse-Grained Simulations

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 36 ◽  
Author(s):  
Vladimir Rudyak ◽  
Elizaveta Efimova ◽  
Daria Guseva ◽  
Alexander Chertovich
Keyword(s):  
Network Topology ◽  
Dissipative Particle Dynamics ◽  
Polymer Network ◽  
Polymer Networks ◽  
Covalent Bond ◽  
Mesh Size ◽  
Coarse Grained ◽  
Topological Parameters ◽  
Thermoset Polymer ◽  
Plasticizer Concentration

The formation of a thermoset polymer network is a complex process with great variability. In this study, we used dissipative particle dynamics and graph theory tools to investigate the curing process and network topology of a phthalonitrile thermoset to reveal the influence of initiator and plasticizer concentration on its properties. We also propose a novel way to characterize the network topology on the basis of two independent characteristics: simple cycle length (which is mainly affected by the initiator amount) and the number of simple cycles passing through a single covalent bond (which is determined primarily by plasticizer concentration). These values can be treated in the more familiar terms of network “mesh size” and “sponginess”, correspondingly. The combination of these two topological parameters allows one to characterize any given network in an implicit but precise way and predict the resulting network properties, including the mechanical modulus. We believe that the same approach could be useful for other polymer networks as well, including rubbers and gels.

scholarly journals Small Oligonucleotides Detection in Three-Dimensional Polymer Network of DNA-PEG Hydrogels

2021 ◽  
Author(s):  
Alessia Mazzarotta ◽  
Tania Maristella Caputo ◽  
Luca Raiola ◽  
Edmondo Battista ◽  
Paolo Antonio Netti ◽  
...  
Keyword(s):  
Polymer Network ◽  
Three Dimensional ◽  
Mesh Size ◽  
Short Oligonucleotide ◽  
Dna Oligonucleotides ◽  
Hydrogel Network ◽  
Displacement Assay ◽  
Oligonucleotide Detection ◽  
Biomolecules Detection ◽  
And Diffusion

The control of the three-dimensional (3D) polymer network structure is important for permselective materials when specific biomolecules detection is needed. Here we investigate conditions to obtain a tailored hydrogel network that combine both molecular filtering and molecular capture capabilities for biosensing applications. Along this line short oligonucleotide detection in a displacement assay is set within PEGDA hydrogels synthetized by UV radical photopolymerization. To provide insights on the molecular filter capability, diffusion studies of several probes (sulforhodamine G and dextrans) with different hydrodynamic radii were carried out using NMR technique. Moreover, fluorometric analyses of hybridization of DNA oligonucleotides inside PEGDA-hydrogels shed light on the mechanisms of recognition in 3D, highlighting that mesh size and crowding effect greatly impact of hybridization mechanism onto polymer network. Finally, we found the best probe density and diffusion transport conditions to allow the specific oligonucleotide capture and detection inside PEGDA-hydrogels for oligonucleotide detection and the filtering out of higher molecular weight molecules.

scholarly journals Single-Macromolecular Level Imaging of a Hydrogel Structure

2021 ◽  
Author(s):  
Ryuji Kiyama ◽  
Takayuki Nonoyama ◽  
Sedlacik Tomas ◽  
Hiroshi Jinnai ◽  
Jian Ping Gong
Keyword(s):  
Polymer Network ◽  
Mesh Size ◽  
Fixation Method ◽  
Gel Properties ◽  
Cell Scaffolds ◽  
Transmission Electron ◽  
Hydrogel Network ◽  
Network Observation ◽  
Surface Network ◽  
First Time

Hydrogels are promising materials for several applications, including cell scaffolds and artificial load-bearing substitutes (cartilages, ligaments, tendons, etc.). Direct observation of the nanoscale polymer network of hydrogels is essential in understanding its properties. However, imaging of individual network strands at the molecular level is not achieved yet due to the lack of suitable methods. Herein, for the first time, we developed a novel mineral-staining method and network fixation method for transmission electron microscopy observation to visualize the hydrogel network in its unperturbed conformation with nanometer resolution. Surface network observation indicates that the length of surface dangling chains, which play a major role in friction and wetting, can be estimated from the gel mesh size. Moreover, bulk observations reveals a hierarchical formation mechanism of gel heterogeneity. These observations have the great potential to advance gel science by providing comprehensive perspective that link bulk gel properties with nanoscale.

scholarly journals pH-Responsive Succinoglycan-Carboxymethyl Cellulose Hydrogels with Highly Improved Mechanical Strength for Controlled Drug Delivery Systems

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3197
Author(s):  
Younghyun Shin ◽  
Dajung Kim ◽  
Yiluo Hu ◽  
Yohan Kim ◽  
In Ki Hong ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Mechanical Strength ◽  
Carboxymethyl Cellulose ◽  
Polymer Network ◽  
Controlled Drug Release ◽  
Interpenetrating Polymer Network ◽  
Ph Responsive ◽  
Hek 293 ◽  
Natural Polysaccharide ◽  
293 Cells

Carboxymethyl cellulose (CMC)-based hydrogels are generally superabsorbent and biocompatible, but their low mechanical strength limits their application. To overcome these drawbacks, we used bacterial succinoglycan (SG), a biocompatible natural polysaccharide, as a double crosslinking strategy to produce novel interpenetrating polymer network (IPN) hydrogels in a non-bead form. These new SG/CMC-based IPN hydrogels significantly increased the mechanical strength while maintaining the characteristic superabsorbent property of CMC-based hydrogels. The SG/CMC gels exhibited an 8.5-fold improvement in compressive stress and up to a 6.5-fold higher storage modulus (G′) at the same strain compared to the CMC alone gels. Furthermore, SG/CMC gels not only showed pH-controlled drug release for 5-fluorouracil but also did not show any cytotoxicity to HEK-293 cells. This suggests that SG/CMC hydrogels could be used as future biomedical biomaterials for drug delivery.

Strong anisotropic hydrogels with ion transport capability via reswelling contrast of two oriented polymer networks

2021 ◽  
Author(s):  
Wei Cui ◽  
Menghan Pi ◽  
Ruijie Zhu ◽  
Zetao Xiong ◽  
Rong Ran
Keyword(s):  
Ion Transport ◽  
Mechanical Strength ◽  
Polymer Networks ◽  
Oriented Polymer ◽  
High Mechanical Strength

The reswelling disparity of two polymer components with contrasting persistence lengths leads to the formation of anisotropic hydrogels with soft/stiff hybridized structures, resulting in high mechanical strength and ion transport capability.

scholarly journals Determine Mesh Size through Monomer Mean-Square Displacement

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1405 ◽  
Author(s):  
Ji-Xuan Hou
Keyword(s):  
Main Parameter ◽  
Dynamic Method ◽  
Mean Square Displacement ◽  
Mesh Size ◽  
Step Length ◽  
Tube Diameter ◽  
Mean Square ◽  
Simulation Data ◽  
Polymer Systems ◽  
Entangled Polymer

A dynamic method to determine the main parameter of the tube theory through monomer mean-square displacement is discussed in this paper. The tube step length can be measured from the intersection of the slope- 1 2 line and the slope- 1 4 line in log-log plot, and the tube diameter can be obtained by recording the time at which g 1 data start to leave the slope- 1 2 regime. According to recent simulation data, the ratio of the tube step length to the tube diameter was found to be about 2 for different entangled polymer systems. Since measuring the tube diameter does not require g 1 data to reach the slope- 1 4 regime, this could be the best way to find the entanglement length from microscopic consideration.

The effect of blob size in polymer networks on nanoparticle-mediated adhesion of hydrogels

Soft Matter ◽  
2019 ◽  
Vol 15 (48) ◽  
pp. 9942-9948
Author(s):  
Sohyun Kim ◽  
Tae Hui Kang ◽  
Gi-Ra Yi
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Pore Diameter ◽  
Physical Adsorption ◽  
Mesoporous Silica Nanoparticles ◽  
Polymer Networks ◽  
Mesh Size ◽  
Adhesion Energy ◽  
Polymer Chains

Mesoporous silica nanoparticles can be used as an adhesive for hydrogels due to their physical adsorption to polymer chains, in which adhesion energy can be affected by the ratio of mesh size and pore diameter.

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