title: When Colloidal Particles Become Polymer Coils.
abstract: This work concerns interfacial adsorption and attachment of swollen microgel with low- to medium-level cross-linking density. Compared to colloids that form a second, dispersed phase, the suspended swollen microgel particles are ultrahigh molecular weight molecules, which are dissolved like a linear polymer, so that solvent and solute constitute only one phase. In contrast to recent literature in which microgels are treated as particles with a distinct surface, we consider solvent-solute interaction as well as interfacial adsorption based on the chain segments that can form trains of adsorbed segments and loops protruding from the surface into the solvent. We point out experimental results that support this discrimination between particles and microgels. The time needed for swollen microgels to adsorb at the air/water interface can be 3 orders of magnitude shorter than that for dispersed particles and decreases with decreasing cross-linking density. Detailed analysis of the microgels deformation, in the dry state, at a solid surface enabled discrimination particle like microgel in which case spreading was controlled predominantly by the elasticity and molecule like adsorption characterized by a significant overstreching, ultimately leading to chain scission of microgel strands. Dissipative particle dynamics simulations confirms the experimental findings on the interfacial activity and spreading of microgel at liquid/air interface.
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mourran
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.
authors.forename: Yaodong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Physics Department, Lomonosov Moscow State University , Moscow 119991, Russian Federation.
authors.forename: Rustam A
authors.initials: RA
authors.lastname: Gumerov
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.|Physics Department, Lomonosov Moscow State University , Moscow 119991, Russian Federation.
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Rudov
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.|Physics Department, Lomonosov Moscow State University , Moscow 119991, Russian Federation.
authors.forename: Igor I
authors.initials: II
authors.lastname: Potemkin
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.
authors.forename: Andrij
authors.initials: A
authors.lastname: Pich
authors.affiliation: DWI - Leibniz Institute for Interactive Materials, and Functional Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , Forckenbeckstr. 50, 52056 Aachen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Möller