Shear responsive surfaces offer potential advances in a number of applications. Surface functionalisation using polymer brushes is one route to such properties, particularly in the case of entangled polymers. We report on neutron reflectometry measurements of polymer brushes in entangled polymer solutions performed under controlled shear, as well as coarsegrained computer simulations corresponding to these interfaces. Here we show a reversible and reproducible collapse of the brushes, increasing with the shear rate. Using two brushes of greatly different chain lengths and grafting densities, we demonstrate that the dynamics responsible for the structural change of the brush are governed by the free chains in solution rather than the brush itself, within the range of parameters examined. The phenomenon of the brush collapse could find applications in the tailoring of nanosensors, and as a way to dynamically control surface friction and adhesion.

Neutron scattering techniques offer several unique opportunities in materials research. However, most neutron scattering experiments suffer from the limited flux available at current facilities. This limitation becomes even more severe if time‐resolved or kinetic experiments are performed. A new method has been developed which overcomes these limitations when a reversible process is studied, without any compromise on resolution or beam intensity. It is demonstrated that, by recording in absolute time the neutron detector events linked to an excitation, information can be resolved on sub‐millisecond timescales. Specifically, the concept of the method is demonstrated by neutron reflectivity measurements in time‐of‐flight mode at the Liquids Reflectometer located at the Spallation Neutron Source, Oak Ridge National Laboratory, Tennessee, USA, combined with in situ rheometry. The opportunities and limitations of this new technique are evaluated by investigations of a micellar polymer solution offering excellent scattering contrast combined with high sensitivity to shear.

Small‐angle scattering in grazing‐incidence beam geometry has been applied on a time‐of‐flight neutron instrument to investigate a solid–liquid boundary. Owing to the broad wavelength distribution provided for a specific incident beam angle, the penetration depth of the neutron beam is varied over a wide range in a single measurement. The near surface structures of block copolymer micelles close to silicon substrates with distinct surface energies are resolved. It is observed that the very near surface structure strongly depends on the surface coating, whereas further away from the surface, bulk‐like ordering is found.

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Neutron scattering experiments are a unique tool in material science due to their sensitivity to light elements and magnetic induction. However, for kinetic studies the low brilliance at existing sources poses challenges. In the case of periodic excitations these challenges can be overcome by binning the scattering signal according to the excitation state of the sample. To advance into this direction we have performed polarised and time resolved grazing incidence neutron scattering measurements on an aqueous solution of the polymer F127 mixed with magnetic nano-particles. Magnetic nano-composites like this provide magnetically tuneable properties of the polymer crystal as well as magnetic meta-crystals. Even though the grazing incidence small angle scattering and polarised signals are too weak to be evaluated at this stage we demonstrate that such experiments are feasible. Moreover, we show that the intensity of the 111 Bragg peak of the fcc micellar crystal depends on the actual shear rate, with the signal being maximised when the shear rate is lowest (and vice-versa).