Polyelectrolyte Polysaccharide–Gelatin Complexes: Rheology and Structure

General features of rheological properties and structural peculiarities of polyelectrolyte polysaccharide–gelatin complexes were discussed in this paper. Experimental results were obtained for typical complexes, such as κ-carrageenan–gelatin, chitosan–gelatin and sodium alginate–gelatin complexes. A rheological method allows us to examine the physical state of a complex in aqueous phase and the kinetics of the sol–gel transition and temperature dependences of properties as a result of structural changes. The storage modulus below the gelation temperature is constant, which is a reflection of the solid-like state of a material. The gels of these complexes are usually viscoplastic media. The quantitative values of the rheological parameters depend on the ratio of the components in the complexes. The formation of the structure as a result of strong interactions of the components in the complexes was confirmed by UV and FTIR data and SEM analysis. Interaction with polysaccharides causes a change in the secondary structure of gelatin, i.e., the content of triple helices in an α-chain increases. The joint analysis of the structural and rheological characteristics suggests that the formation of additional junctions in the complex gel network results in increases in elasticity and hardening compared with those of the native gelatin.

Download Full-text

Rheological Properties of Fish Gelatin Modified with Sodium Alginate

Polymers ◽

10.3390/polym13050743 ◽

2021 ◽

Vol 13 (5) ◽

pp. 743

Author(s):

Svetlana R. Derkach ◽

Daria S. Kolotova ◽

Nikolay G. Voron’ko ◽

Ekaterina D. Obluchinskaya ◽

Alexander Ya. Malkin

Keyword(s):

Elastic Modulus ◽

Transition Temperature ◽

Sodium Alginate ◽

Rheological Behavior ◽

Sol Gel ◽

Rheological Parameters ◽

Fish Gelatin ◽

Mass Ratio ◽

Sol Gel Transition ◽

Gel Transition

Polyelectrolyte complexes of sodium alginate and gelatin obtained from cold-blooded fish were studied for potential application as structure-forming agents in food hydrogels. The mass ratio of sodium alginate to gelatin plays a decisive role in the sol-gel transition and rheological behavior of the complexes. Differences in the sol-gel transition temperature were observed upon heating and cooling, as is typical for such materials. We investigated the characteristics of this transition by measuring the isothermal changes in the elastic modulus over time at a constant frequency and the transition temperature at a range of frequencies. The kinetic nature of this transition depends on the composition of the complexes. A characteristic alginate-gelatin mass ratio is the ratio at which maximum transition temperature as well as elastic modulus and viscosity (rheological parameters) values are obtained; the characteristic mass ratio for these complexes was found to be 0.06. Calculation of the ionic group ratios in the biopolymers that form complexes and comparison of these data with the turbidimetric titration results clarified the origin of these maxima. Measuring the viscoelastic properties and the creep-elastic recoil of the samples allowed us to characterize these materials as viscoelastic media with a viscosity in the order of 103–104 Pa·s and an elastic modulus in the order of 102–103 Pa. These values drastically decrease at a certain stress threshold, which can be treated as the gel strength limit. Therefore, the observed rheological behavior of gels formed by fish gelatin modified with sodium alginate characterizes them as typical viscoelastic soft matter.

Download Full-text

Structural Changes and Oscillations during the Sol-Gel Transition in Silica Gel Glass as Probed by Pyrene Excimerization

Unconventional Photoactive Solids ◽

10.1007/978-1-4613-0727-3_18 ◽

1988 ◽

pp. 179-183

Author(s):

Vered R. Kaufman ◽

David Avnir

Keyword(s):

Silica Gel ◽

Structural Changes ◽

Sol Gel ◽

Sol Gel Transition ◽

Gel Transition

Download Full-text

Viscoelasticity of Dental Tissue Conditioners during the Sol-gel Transition

Journal of Dental Research ◽

10.1177/154405910508400416 ◽

2005 ◽

Vol 84 (4) ◽

pp. 376-381 ◽

Cited By ~ 10

Author(s):

H. Murata ◽

H. Chimori ◽

T. Hamada ◽

J.F. McCabe

Keyword(s):

Molecular Weight ◽

Sol Gel ◽

Influential Factor ◽

Rheological Parameters ◽

Dental Tissue ◽

Ethanol Content ◽

Composition And Structure ◽

Wide Range ◽

Sol Gel Transition ◽

Gel Transition

Formation of tissue conditioners is a process of polymer chain entanglements. This study evaluated the influence of composition and structure on dynamic viscoelasticity of concentrated polymer solutions based on poly(ethyl methacrylate) (PEMA) used as tissue conditioners through the sol-gel transition. The hypothesis was that the ethanol content is the most influential factor in determining gelation speed. Rheological parameters were determined with the use of a controlled-stress rheometer. Analysis of variance by orthogonal array L16(45) indicated that the strong polar bonding of ethanol (contribution ratio ρ = 53.8%; confirming the hypothesis) and molecular weight of polymer powders (ρ = 26.7%) had a greater influence on the gelation times of PEMA-based systems than did the molar volume of plasticizers (ρ = 9.0%) and concentration of polymers ( i.e., powder/liquid ratio) (ρ = 4.5%). The results suggest that the gelation of tissue conditioners based on PEMA can be controlled over a wide range by varying the polymer molecular weight, and especially ethanol content.

Download Full-text

Sol-gel transition in silica alkaline solutions. A NMR study

Journal de Chimie Physique ◽

10.1051/jcp/1994910901 ◽

1994 ◽

Vol 91 ◽

pp. 901-908 ◽

Cited By ~ 2

Author(s):

H Zanni ◽

P Nieto ◽

L Fernandez ◽

R Couty ◽

P Barret ◽

...

Keyword(s):

Sol Gel ◽

Alkaline Solutions ◽

Nmr Study ◽

Sol Gel Transition ◽

Gel Transition

Download Full-text

Mesoscopic gelation of chitosan and genipin at below critical concentrations

10.26434/chemrxiv.5487172.v1 ◽

2017 ◽

Author(s):

Christoph Engwer ◽

Ronja Loy ◽

Ioannis S. Chronakis ◽

Ana C. Mendes ◽

Francisco M. Goycoolea

Keyword(s):

Sol Gel ◽

Crosslinking Agent ◽

Small Deformation ◽

Macroscopic Appearance ◽

Critical Concentrations ◽

Gelation Kinetics ◽

Gardenia Jasminoides ◽

Sol Gel Transition ◽

Low Cytotoxicity ◽

High Concentrations

Genipin is increasingly used as a crosslinking agent for chitosans due to its low cytotoxicity as a naturally occurring extract of the plant <i>Gardenia jasminoides</i>. Genipin reacts with the primary amino groups of chitosan to form blue hydrogels. We studied the gelation kinetics of different chitosans varying in their properties (molar mass 34 000-213 000 g mol<sup>-1</sup>, degree of acetylation 9-20%) and genipin in detail. We found that critical sol-gel transition times obtained from dynamic light scattering were in good agreement with the results obtained by small deformation oscillatory rheometry and microviscosimetry at high concentrations of chitosan. However, at below critical concentrations, we found a second regime of gelation that followed the same Ross-Murphy's gelation kinetics. The macroscopic appearance of these samples was a suspension of weak gel-like particles that were sensitive to mechanical forces. We believe that the material is a mesoscopic gel, as described for other polymers. To the best of our knowledge, this is the first time that this phenomenon has been described for the gelling system of chitosan and genipin.

Download Full-text

Sol-gel transition in agar-gelatin mixtures studied with transient elastography

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2006.1621498 ◽

2006 ◽

Vol 53 (4) ◽

pp. 716-723 ◽

Cited By ~ 26

Author(s):

J.-L. Gennisson ◽

G. Cloutier

Keyword(s):

Transient Elastography ◽

Sol Gel ◽

Sol Gel Transition ◽

Gel Transition

Download Full-text

Synthesis of Nanogels: Current Trends and Future Outlook

Gels ◽

10.3390/gels7020036 ◽

2021 ◽

Vol 7 (2) ◽

pp. 36

Author(s):

Emanuele Mauri ◽

Sara Maria Giannitelli ◽

Marcella Trombetta ◽

Alberto Rainer

Keyword(s):

3D Printing ◽

Ad Hoc ◽

Sol Gel ◽

Controlled Polymerization ◽

Current Trends ◽

Chip Technology ◽

Physico Chemical ◽

Physical Interactions ◽

Sol Gel Transition ◽

Gel Transition

Nanogels represent an innovative platform for tunable drug release and targeted therapy in several biomedical applications, ranging from cancer to neurological disorders. The design of these nanocarriers is a pivotal topic investigated by the researchers over the years, with the aim to optimize the procedures and provide advanced nanomaterials. Chemical reactions, physical interactions and the developments of engineered devices are the three main areas explored to overcome the shortcomings of the traditional nanofabrication approaches. This review proposes a focus on the current techniques used in nanogel design, highlighting the upgrades in physico-chemical methodologies, microfluidics and 3D printing. Polymers and biomolecules can be combined to produce ad hoc nanonetworks according to the final curative aims, preserving the criteria of biocompatibility and biodegradability. Controlled polymerization, interfacial reactions, sol-gel transition, manipulation of the fluids at the nanoscale, lab-on-a-chip technology and 3D printing are the leading strategies to lean on in the next future and offer new solutions to the critical healthcare scenarios.

Download Full-text