Chemical Cross-Linking of Anatase Nanoparticle Thin Films for Enhanced Mechanical Properties

Collagen-based materials were prepared and their properties were studied. The shape of collagen materials was as follows: thin films, hydrogels, and sponges. Microstructure and mechanical properties of films and sponges were studied. The effect of cross-linking agents and the effect of synthetic polymer on the properties of collagen materials were studied and analyzed. Collagen-based materials can be considered as potential biomaterials in tissue engineering.

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Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels

Materials ◽

10.3390/ma12071066 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1066 ◽

Cited By ~ 4

Author(s):

Tim Huber ◽

Sean Feast ◽

Simone Dimartino ◽

Wanwen Cen ◽

Conan Fee

Keyword(s):

Mechanical Properties ◽

Network Formation ◽

Aqueous Sodium Hydroxide ◽

Cross Linking ◽

Processing Conditions ◽

Hot Press ◽

Thermal Gelation ◽

Complex Shapes ◽

Bond Network ◽

Chemical Cross Linking

Cellulose-based hydrogels were prepared by dissolving cellulose in aqueous sodium hydroxide (NaOH)/urea solutions and casting it into complex shapes by the use of sacrificial templates followed by thermal gelation of the solution. Both the gelling temperatures used (40–80 °C), as well as the method of heating by either induction in the form of a water bath and hot press or radiation by microwaves could be shown to have a significant effect on the compressive strength and modulus of the prepared hydrogels. Lower gelling temperatures and shorter heating times were found to result in stronger and stiffer gels. Both the effect of physical cross-linking via the introduction of additional non-dissolving cellulosic material, as well as chemical cross-linking by the introduction of epichlorohydrin (ECH), and a combination of both applied during the gelation process could be shown to affect both the mechanical properties and microstructure of the hydrogels. The added cellulose acts as a physical-cross-linking agent strengthening the hydrogen-bond network as well as a reinforcing phase improving the mechanical properties. However, chemical cross-linking of an unreinforced gel leads to unfavourable bonding and cellulose network formation, resulting in drastically increased pore sizes and reduced mechanical properties. In both cases, chemical cross-linking leads to larger internal pores.

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Mechanically Reinforced Gelatin Hydrogels by Introducing Slidable Supramolecular Cross-Linkers

Polymers ◽

10.3390/polym11111787 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1787 ◽

Cited By ~ 6

Author(s):

Dae Hoon Lee ◽

Atsushi Tamura ◽

Yoshinori Arisaka ◽

Ji-Hun Seo ◽

Nobuhiko Yui

Keyword(s):

Mechanical Properties ◽

Stress Concentration ◽

Cross Linking ◽

Supramolecular Polymer ◽

Poly Ethylene Glycol ◽

Physical Force ◽

Adhesive Material ◽

Cell Adhesive ◽

Poly Ethylene ◽

Chemical Cross Linking

Tough mechanical properties are generally required for tissue substitutes used in regeneration of damaged tissue, as these substitutes must be able to withstand the external physical force caused by stretching. Gelatin, a biopolymer derived from collagen, is a biocompatible and cell adhesive material, and is thus widely utilized as a component of biomaterials. However, the application of gelatin hydrogels as a tissue substitute is limited owing to their insufficient mechanical properties. Chemical cross-linking is a promising method to improve the mechanical properties of hydrogels. We examined the potential of the chemical cross-linking of gelatin hydrogels with carboxy-group-modified polyrotaxanes (PRXs), a supramolecular polymer comprising a poly(ethylene glycol) chain threaded into the cavity of α-cyclodextrins (α-CDs), to improve mechanical properties such as stretchability and toughness. Cross-linking gelatin hydrogels with threading α-CDs in PRXs could allow for freely mobile cross-linking points to potentially improve the mechanical properties. Indeed, the stretchability and toughness of gelatin hydrogels cross-linked with PRXs were slightly higher than those of the hydrogels with the conventional chemical cross-linkers 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS). In addition, the hysteresis loss of gelatin hydrogels cross-linked with PRXs after repeated stretching and relaxation cycles in a hydrated state was remarkably improved in comparison with that of conventional cross-linked hydrogels. It is considered that the freely mobile cross-linking points of gelatin hydrogels cross-linked with PRXs attenuates the stress concentration. Accordingly, gelatin hydrogels cross-linked with PRXs would provide excellent mechanical properties as biocompatible tissue substitutes exposed to a continuous external physical force.

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Enhanced Mechanical Properties in Cellulose Nanocrystal–Poly(oligoethylene glycol methacrylate) Injectable Nanocomposite Hydrogels through Control of Physical and Chemical Cross-Linking

Biomacromolecules ◽

10.1021/acs.biomac.5b01598 ◽

2016 ◽

Vol 17 (2) ◽

pp. 649-660 ◽

Cited By ~ 108

Author(s):

Kevin J. De France ◽

Katelyn J. W. Chan ◽

Emily D. Cranston ◽

Todd Hoare

Keyword(s):

Mechanical Properties ◽

Cellulose Nanocrystal ◽

Cross Linking ◽

Glycol Methacrylate ◽

Nanocomposite Hydrogels ◽

Oligoethylene Glycol ◽

Physical And Chemical ◽

Chemical Cross Linking

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Supercritical Fluid Treatment to Improve Dielectric and Mechanical Properties of Porous ULK Thin Films

MRS Proceedings ◽

10.1557/proc-0914-f02-08 ◽

2006 ◽

Vol 914 ◽

Cited By ~ 1

Author(s):

Julien Beynet ◽

Vincent Jousseaume ◽

Alain Madec ◽

Bruno Rémiat ◽

N. Dominique Albérola ◽

...

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Dielectric Constant ◽

Thermal Annealing ◽

Supercritical Fluid ◽

Hybrid Film ◽

Cross Linking ◽

Residue Removal ◽

Deposited Film ◽

Dielectric And Mechanical Properties

AbstractSpin-on glass organosilicate films are promising Ultra Low-ĸ (ULK) interlevel dielectric candidates in which porosity can be created by incorporating thermally labile porogens. The as-deposited film (called the hybrid film) consists of a methylsilsesquioxane (MSQ) matrix and an organic porogen. The standard porogen removal step consists of a 450°C thermal annealing. However, it leaves polymeric residues suspected to cause an incomplete matrix crosslinking and, consequently, to be detrimental to the porous film's electrical and mechanical properties. In this work, a supercritical fluid (SCF) treatment, performed on a 200 mm tool, was added before the thermal annealing with the intent of improving the dielectric properties. Electrical and mechanical properties were greatly enhanced: the dielectric constant was reduced from 2.5 to 2.1 and the Young's modulus was increased from 2 GPa to 3 GPa. Porogen residue removal and cross-linking improvements were investigated by Fourier Transform Infrared (FTIR) spectroscopy in transmission and multiple internal reflection (MIR) mode.

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Enhancement of the mechanical properties of lysine-containing peptide-based supramolecular hydrogels by chemical cross-linking

Soft Matter ◽

10.1039/d1sm01136g ◽

2021 ◽

Author(s):

Libby Jane Marshall ◽

Olga Matsarskaia ◽

Ralf Schweins ◽

Dave Adams

Keyword(s):

Mechanical Properties ◽

Lysine Residue ◽

Cross Linking ◽

The Cross ◽

Chemical Cross Linking

Exposure of lysine-containing peptide-based gelators to the cross-linking agent glutaraldehyde allows tuning of gel mechanical properties. The effect of cross-linking depends on the position of the lysine residue in the...

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