Modelling and confocal microscopy of biopolymer mixtures in confined geometries
Artikel i vetenskaplig tidskrift, 2010

The morphology of a phase separating and gelling biopolymer mixture (gelatin-maltodextrin) is strongly affected not only by thermodynamic conditions, but also by the presence of a restricted geometry. Phase separation within droplets is analysed using confocal laser scanning microscopy and image analysis by varying concentration (4% gelatin and 4%-7.3% maltodextrin), quench temperature (10 degrees C to 25 degrees C) and droplet diameters (10 mu m-120 mu m). The effects of confinement as well as quench temperature increase with increasing maltodextrin concentration in 120 mu m sized droplets. In small droplets below 20 mu m, the confinement and surface dominate the microstructure. The trends observed show good agreement with predictions of the elastic Lennard-Jones (ELJ) model, adapted to handle confinement, that is solved via conventional molecular dynamics. A one-dimensional spin-chain with variable bond length is furthermore introduced and shown to capture a number of qualitative behaviors. The findings reveal that the confined biopolymer mixture can be characterized by the very few parameters of the ELJ model, which incorporates the basic mechanism of short range attraction (collapse, crystallization) versus long range elastic repulsion (osmotic penalty). Accordingly, the study suggests that the model provides a handle towards the morphological design of binary polymer mixtures in microcapsules, droplets or other geometries of well defined size and shape.

gelatin

2-dimensional gels

surfaces

mixtures

transitions

phase-separation

kinetics

gelatin/maltodextrin

directed spinodal decomposition

Författare

Sophia Fransson

Swedish Institute for Food and Biotechnology

O. Peleg

Biozentrum University of Basel

Eidgenössische Technische Hochschule Zürich (ETH)

Niklas Lorén

SuMo Biomaterials

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

Anne-Marie Hermansson

SuMo Biomaterials

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

M. Kroger

Eidgenössische Technische Hochschule Zürich (ETH)

Soft Matter

1744-683X (ISSN) 1744-6848 (eISSN)

Vol. 6 2713-2722

Ämneskategorier

Kemiteknik

DOI

10.1039/b926562g