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Interaction forces and molecular adhesion between pre-adsorbed poly(ethylene imine) layers

Title data

Pericet-Camara, Ramon ; Papastavrou, Georg ; Behrens, Sven H. ; Helm, Christiane A. ; Borkovec, Michal:
Interaction forces and molecular adhesion between pre-adsorbed poly(ethylene imine) layers.
In: Journal of Colloid and Interface Science. Vol. 296 (April 2006) Issue 2 . - pp. 496-506.
ISSN 1095-7103
DOI: https://doi.org/10.1016/j.jcis.2005.09.033

Official URL: Volltext

Abstract in another language

Interaction forces between pre-adsorbed layers of branched poly(ethylene imine) (PEI) of different molecular mass were studied with the colloidal probe technique, which is based on atomic force microscopy (AFM). During approach, the long-ranged forces between the surfaces are repulsive due to overlap of diffuse layers down to distances of a few nanometers, whereby regulation of the surface charge is observed. The ionic strength dependence of the observed diffuse layer potentials can be rationalized with a surface charge of 2.3 mC/m2. The forces remain repulsive down to contact, likely due to electro-steric interactions between the PEI layers. These electro-steric forces have a range of a few nanometers and appear to be superposed to the force originating from the overlap of diffuse layers. During retraction of the surfaces, erratic attractive forces are observed due to molecular adhesion events (i.e., bridging adhesion). The frequency of the molecular adhesion events increases with increasing the ionic strength. The force response of the PEI segments is dominated by rubber-like extension profiles. Strong adhesion forces are observed for low molecular mass PEI at short distances directly after separation, while for high molecular mass weaker adhesion forces at larger distances are more common. The work of adhesion was estimated by integrating the retraction force profiles, and it was found to increase with the ionic strength.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Physical Chemistry II
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors > Chair Physical Chemistry II - Univ.-Prof. Dr. Andreas Fery
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Physical Chemistry II
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors
Result of work at the UBT: No
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 13 Sep 2017 08:30
Last Modified: 13 Sep 2017 08:30
URI: https://eref.uni-bayreuth.de/id/eprint/39581