Disguise tactics: Peptide–polymer hybrid nanotubes are constructed in which self‐assembled cyclic peptides govern the structure, and a synthetic polymer coating determines the surface chemistry. Formation of the latter is initiated in situ from preorganized peptide building blocks. The picture shows an AFM image of nanotubes on a silicon wafer.

The correlation between the morphology of mixed polymer brushes and fluctuations of the grafting points is investigated by single-chain-in-mean-field simulations and experiments. The local topography of two types of mixed polystyrene-polymethylmethacrylate (PS-PMMA) brushes that differ in their modes of attachment has been studied during repeated microphase separation into laterally structured and homogeneous morphologies upon changing solvents. In the first type of brush (conventional), each of the surface-attached initiator groups starts the growth of either a PS or a PMMA chain in a random fashion. In the second case (Y-shaped mixed brushes), two chains of different types are attached to the same anchor group on the substrate. Whereas in the first case statistical fluctuations of the chemical composition occur on a local scale, such composition fluctuations are strongly suppressed in the latter case. The microphase-separated morphology is similar in both cases, but Y-shaped brushes exhibit a significantly weaker domain memory than do conventional PS-PMMA mixed brushes. The results of the experiment are compared with simulations, and a simple phenomenological argument and qualitative agreement are found. The observations demonstrate that small fluctuations in the grafting points are amplified by the microphase separation and nucleate the location of the domains in the mixed brush.

Polystyrene−poly(methyl methacrylate) (PS−PMMA) mixed brushes synthesized by surface-initiated polymerization show nanophase separation into defined pattern depending on the molecular parameters of the brushes. Two sets of mixed brushes are studied:  (i) with fixed grafting density and molecular weight of the PS chains, but differing in the molecular weight of PMMA polymer, and (ii) with varying grafting density of the PMMA chains while that of the PS chains and the molecular weight of PS and PMMA chains are kept constant. The local distribution of PS and PMMA chains within the monolayer and the size, shape, and position of the domains constituting the nanopattern are found to vary with the nature of the solvent to which the brushes are exposed. The brushes are treated cyclically first with either a good solvent for both blocks, leading to strong swelling and structure erasure, and then with a selective solvent, which induces the nanophase separation. It was found that in the case of the brush exposed to toluene solvent (good solvent for both polymers) the brush surface exhibiting a small variation in topography has a heterogeneous surface composition, with the nanoscopic areas having only PS or PMMA chains at the surface. When the brush is treated with acetone solvent, which is better for the PMMA chains, the surface consists only of PMMA chains, and the topography assumes a more pronounced relief. We introduce the concept of the local domain memory effect of the brushes, i.e., whether the brush locally forms always the same pattern or if the local assembly of the domains emerges in different places every time the transition to the structured state occurs.