Effect of end-group sticking energy on the properties of polymer brushes: Comparing experiment and theory

Abstract

Using surface force balance measurements we have established that polystyrene chains bearing three zwitterionic groups have a higher end-group sticking energy than equivalent chains bearing a single zwitterionic group. In a good solvent, polystyrene chains end-functionalized with three zwitterionic groups form brushes of a higher surface coverage than those bearing a single zwitterion. The increase in surface coverage is slow compared with the initial formation of the brush. Measurements of the refractive index allow us to directly quantify the variation of surface coverage, permitting comparison with models for the kinetics of brush formation based on scaling theory and an analytical self-consistent field. We find qualitative support for associating the kinetic barrier with the energy required for an incoming chain to stretch as it penetrates the existing brush.

Depletion forces between particles immersed in nanofluids

“…In the presence of the electric double layer force, Zeng et al proposed that  =  -1 (the Debye length), and we suggest that could be generalised as the range of the soft inter-nanoparticle interaction, e.g. the thickness of adsorbed or end-anchored polymer layers on the surface[54][55][56]. The amplitude A 0 in Eq.…”

Structure and Collapse of a Surface-Grown Strong Polyelectrolyte Brush on Sapphire

“…[28][29][30] ). The advantages of grafted-from brushes include the ability to access higher density regimes, due to by-passing the kinetic limitations on graftedto brush density that arise from the slow diffusion of pre-existing polymer chains through a partiallyformed brush 18,[31][32][33] . Also, it is generally straightforward to devise brushes that are strongly surfaceanchored, for example through the use of covalently-anchored self-assembled monolayers of initiator molecules.…”

Desorption of bottle-brush polyelectrolytes from silica by addition of linear polyelectrolytes studied by QCM-D and reflectometry

“…However, competitive adsorption studies [5][6][7][8][9] between (linear) polyelectrolytes, in which polyelectrolytes with different surface affinity compete, are rather few, and to our knowledge there are no reports describing the surface exchange of bottle-brush polyelectrolytes with linear polyelectrolytes. However, there are contributions [10,11] in which surface exchange in brush layers, formed through the adsorption of amphiphilic polymers, has been studied.…”