Colloidal Gelation

Microscopic interactions and emerging elasticity in model soft particulate gels

“…11 also suggest a power law dependence of the various contributions and of the gel elastic modulus on the particle volume fraction (with the caveat that our range of volume fractions here is relatively limited). Such dependence is quite common in colloidal gels although exponents reported in experiments are often between ∼ 3-− 4 [1,15,[66][67][68][69][70] and usually associated with fractal structures. The gel structures considered here are not self-similar and the values we find are closer to those reported in [71][72][73][74] corresponding to quite higher values of the exponent.…”

“…Soft particulate gels can form in a wide range of colloidal suspensions of particles, particle agglomerates or droplets [1][2][3][4][5][6][7][8][9][10][11]. The combination of attractive interparticle interactions, that drive the particle aggregation, with increasing cooperative dynamics, that lead to kinetic arrest, results into the self-assembly of an interconnected space-spanning network structure, which can be very soft but ultimately has solid-like elastic properties [12,13].…”

Rheology of protein-stabilised emulsion gels envisioned as composite networks. 2 - Framework for the study of emulsion gels

“…This approach relies on the hypothesis that there is little distinction between droplets and un-adsorbed proteins in the way each contributes to the properties of the gel of mixture. This is because the most relevant length-scale to study the rheological and microstructural features of colloidal gels appears to be the length-scale of strands of particles [32,33,34,35]. Consequently, the systems are examined at a much larger scale than of the single particles, and the discrepancy in size and structure of the protein aggregates and proteinstabilised droplets is thus assumed not to be critical.…”

Rheology of protein-stabilised emulsion gels envisioned as composite networks 1– Comparison of pure droplet gels and protein gels

“…Emulsion and protein gels form the basis of many food products, such as yoghurt, soft cheese or tofu, where the flocculation of a vegetable or animal milk leads to the formation of a soft solid via aggregation of proteins and fat droplets. This process has been used for millenia in traditional cooking, but a deep understanding of the mechanisms of the physical transformation occurring in these systems only came in recent decades with the study of colloidal gels [1,2,3]. While much effort has been spent in correlating the structure formation and the gel properties with the interparticle interactions [4], there is yet to be a full understanding of food-based colloidal gels, both in terms of fundamental science and of specific applications.…”

“…It has been shown that the exponent A can be related to the fractal dimension of the gels, with the relationship depending on the gelation regime. For gels formed via diffusion limited cluster aggregation, generally at low volume fractions, it was found that A = (3 + D b )/(3 − D f ), where D b is defined as the bond (or backbone) dimension of the network [4,3]. At higher volume fractions, the links between clusters are weaker and A = 1/(3 − D f ) [10].…”