We utilize dynamic light scattering (DLS) and passive microrheology to examine the phase behavior of a supramolecular polymer at very high pressures. The monomer, 2,4-bis(2ethylhexylureido)toluene (EHUT), self-assembles into supramolecular polymeric structures in the non-polar solvent cyclohexane, by means of hydrogen bonding. By varying concentration and temperature at atmospheric pressure, the formation of viscoelastic network (at lower temperatures) and predominantly viscous phases, based on self-assembled tube and filament structures respectively, has been established. The associated changes in the rheological properties have been attributed to a structural thickness transition. Here, we investigate the effects of pressure variation, from atmospheric up to 1 kbar. We construct a temperature-pressure diagram that reveals the predominance of the viscoelastic network phase at high pressures. The transition from viscoelastic network organization of the tubes to a weaker viscous-dominated

We revisit the equilibrium phase diagram of the much-studied model supramolecular polymer, 2,4-bis(2ethylhexylureido)toluene (EHUT) in nonpolar solvents and provide unambiguous evidence of a much richer behavior, characterized by four distinct regimes. Typically, two types of self-assembled structures are formed: tubes (filaments) at higher (lower) concentrations and lower (higher) temperatures. The tube structure forms viscoelastic solutions that had been characterized by rheology, however, without detailed analysis of the experimental signals. Here, we combine rheology and microrheology to establish the complete dynamic phase diagram of EHUT in dodecane. It still comprises two structures, tubes and filaments, with the transition temperature being almost constant over the examined wide concentration range, as confirmed with the help of complementary differential scanning calorimetry measurements. The tubes are found to exist in three dynamic states with increasing concentration, unentangled, partially entangled, and well entangled, which are separated by isolength lines. We present criteria for unambiguously identifying these phases and discuss their distinct concentration and temperature dependencies. The new, complete phase diagram may serve as a guide for investigating other supramolecular polymers with tunable rheology and, more importantly, providing insights into a universal description of one-dimensional self-assembled structures by linking this class of materials with the classic wormlike surfactant micelles, for which the partially and well-entangled regimes were recently elucidated.

Low-power visible light can lead to spectacular nonlinear effects in soft-matter systems. The propagation of visible light through transparent solutions of certain polymers can experience either self-focusing or defocusing nonlinearity, depending on the solvent. We show how the self-focusing and defocusing responses can be captured by a nonlinear propagation model using local spatial and time-integrating responses. We realize a remarkable pattern formation in ternary solutions and model it assuming a linear combination of the self-focusing and defocusing nonlinearities in the constituent solvents. This versatile response of solutions to light irradiation may introduce a new approach for self-written waveguides and patterns.