3.

Reciprocal interactions between droplets and supramolecular copolymers. (A) DF-dependent turbidity traces at λ = 600 nm plotted against time after EDC addition to a mixture of RG₂D (12.3 mM), pSS (20.0 mM) in isolation (control), in the presence of the copolymer (DF = 25%, c = 1 mM) and in the presence of the homopolymer of BTAClick (DF = 100%, c = 0.25 mM) in 5-vol % EtOH/200 mM MES buffer (pH = 5.3) with the extracted lifetime based on an optical density threshold of ΔOD < 0.25. Standard deviations are based on triplicate experiments. (B) Fluorescence microscopy images of droplets formed in the presence of supramolecular copolymers at DF = 25%, with the different droplet diameters based on fluorescence intensity being shown in the bottom right. The supramolecular polymers are stained using coumarin azide (magenta), while the droplet material is stained using NBD-functionalized RG₂N (cyan). (C) Relative compositions of supramolecular polymers inside and outside of the droplets at DF = 25%, calculated based on HPLC; error bars are based on triplicates. (D) Schematic depiction of the proposed protruding fiber formation mechanism driven by the binding of BTAClick-rich material to the droplets and the extension of BTA-rich segments into the dilute phase.