Journal ArticleDOI
Interactions between polymer brushes: Varying the number of end-attaching groups
Iain E. Dunlop,Wuge H. Briscoe,Simon Titmuss,Giorgos Sakellariou,Nikos Hadjichristidis,Jacob Klein +5 more
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TLDR
In this paper, the authors used surface force balance (SFB) to study the normal interactions between polymer brushes, which are self-assembled from solution, and found that the grafting density does not vary significantly between polymers with 1, 2, and 3 end groups.Abstract:
We use a surface force balance (SFB) to study the normal interactions between polymer brushes, which are self-assembled from solution. They consist of polystyrene (PS) chains in toluene (neutral chains in a good solvent) anchored on the interacting mica surfaces via sulfozwitterionic end groups. The properties of the brush depend on the length, N, of the chain, and the energy, αk B T, with which the end group adsorbs on the surface. In contrast to earlier studies where N was varied, we attempt to vary the sticking energy by using polymer chains with one, two, and three zwitterions attached to their ends. We use the theory of Alexander and de Gennes to predict how the normal force profile should vary with a and N, finding, for example, that the brush height L 0 obeys L 0 = a . N 3/5 . α 2/5 . Surprisingly, our measurements show that the grafting density does not vary significantly between polymers with 1, 2, and 3 end groups. This could be attributed to dipole-dipole interactions between the zwitterions themselves. It is also possible that the effect could be kinetic: that the brush is unable to reach its equilibrium state because successive polymer chains are hindered from attaching to the surface by those already in the brush. Measurements on longer time scales will be necessary to determine whether kinetic effects are important.read more
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Journal ArticleDOI
Density effects on collapse, compression and adhesion of thermoresponsive polymer brushes
Ibrahim Bou Malham,Lionel Bureau +1 more
TL;DR: In this article, the authors investigated the thermal response of poly(N-isopropylacrylamide) (PNIPAM) brushes of various grafting densities, grown from plasma-activated mica by means of surface-initiated polymerization.
Journal ArticleDOI
Direct Measurement of Normal and Shear Forces between Surface-Grown Polyelectrolyte Layers†
Iain E. Dunlop,Wuge H. Briscoe,Simon Titmuss,Robert M. J. Jacobs,Vicky L. Osborne,Steve Edmondson,Wilhelm T. S. Huck,Jacob Klein +7 more
TL;DR: X-ray reflectometry measurements confirm the successful formation of polyelectrolyte layers by this method, and Surface-inititated ATRP has the advantages that the polymer chains can be strongly grafted to the substrate, and that high grafting densities should be achievable.
Patent
Compositions of neutral layer for directed self assembly block copolymers and processes thereof
TL;DR: In this article, neutral layer compositions for aligning microdomains of directed selfassembling block copolymers (BCP) have been proposed and used for fabrication of electronic devices.
Journal ArticleDOI
Interaction Forces between Microsized Silica Particles and Weak Polyelectrolyte Brushes at Varying pH and Salt Concentration
Astrid Drechsler,Alla Synytska,Petra Uhlmann,Mahdy M. Elmahdy,Mahdy M. Elmahdy,Manfred Stamm,Friedrich Kremer +6 more
TL;DR: Force measurements between poly(acrylic acid) and P2VP brushes and silica particles revealed a much more complex behavior: a steric repulsion by the swollen brush at low pH values, a complex interplay of attractive and repulsive forces at intermediate pH values and a short-ranged attraction between the collapsed brush and the silica particle at basic pHvalues and high salt concentrations.
Journal ArticleDOI
Nanofluids mediating surface forces.
TL;DR: Recent results on equilibrium and dynamic surface forces between macroscopic surfaces in nanofluids are reviewed, highlighting the overriding trends in the correlation between the physical parameters that characterise nan ofluids and the surface forces they mediate.
References
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Book
Intermolecular and surface forces
TL;DR: The forces between atoms and molecules are discussed in detail in this article, including the van der Waals forces between surfaces, and the forces between particles and surfaces, as well as their interactions with other forces.
Journal ArticleDOI
Polymer brushes: surface-immobilized macromolecules
Bin Zhao,William J. Brittain +1 more
TL;DR: In this article, a review of recent literature on polymer brushes with an emphasis on linear polymer brushes attached to solid substrate surfaces is presented. The following topics are included: (i) theoretical and experimental studies of homopolymer brush structure; (ii) theoretical investigations of diblock copolymer brushes; (iii) preparation of hompolymer brushes by physisorption, grafting to and grafting from methods.
Journal ArticleDOI
Polymers at an interface; a simplified view
TL;DR: An elementary description of polymers adsorbed, or terminally attached, at an interface is given in this paper, restricted to linear, flexible, neutral chains in good solvents.