Suppression of Mesoscopic Order by Complementary Interactions in Supramolecular Polymers

Abstract

We show here that complementary interactions can suppress mesoscopic order and thus lead to a counterintuitive change in material properties. We present results for telechelic supramolecular polymers based on poly(propylene oxide) (PPO), thymine (Thy), and diaminotriazine (DAT). The self-complementary systems based on Thy exhibit lamellar order and 2D crystallization of Thy in the bulk. We show that the microphase segregation is inhibited by addition of DAT: the strong complementary Thy-DAT interaction inhibits crystallization of thymine in microdomains and lamellar structuration. As a result, the supramolecular polymer with only weakly self-complementary stickers is a solid, whereas the supramolecular polymer with strongly complementary stickers is a liquid.

Molecular Approach to Supramolecular Polymer Assembly by Small Angle Neutron Scattering

“…The disordered nature of the mixture was found also in a recent investigation of the bulk system by SAXS. 22,54 From this we can safely conclude that the presented polymer RPA model delivers a good description of both the characteristic length scale (peak position) and number of supramolecularly assembling units (peak height). We emphasize that the scattering length densities were fixed to the theoretical values and only the interaction parameters between the blocks, N agg and l st needed to be optimized.…”

“…22,54 The incompatibility between the blocks itself is somewhat larger than the empirical estimation. Although very high, they do not lead to the formation of ordered microscaled aggregation and evidence a disordered state.…”

“…52 However it is significantly lower than in a recently temperature-dependent NMR−viscosity study on the identical system (K assn,Tol ≈ 2.2 × 10 4 M −1 ). 54 The classical determination of association constants K assn,Tol by NMR titration is based on a change in the chemical environment of the binding hydrogen upon complexation. 81−85 Therefore, the observed value strongly reflects the local environment of the hydrogen bond but does not give any direct information about the aggregation type between different macromonomers in a supramolecular system.…”

“…Also, in the recent study by Cortese et al, 54 the role of the solvent was discussed in terms of viscosities measurements. The enhancement of the latter in toluene was ascribed to small aggregates of constant size consisting of six macromonomers, held together by π−π interactions.…”

Supramolecular network-based self-healing polymer materials

“…Much attention is attributed to raising the strength of a hydrogen bond. Some polymeric materials with well-defined hydrogen bond groups on chains are reported, such as the 2-ureido-1[ 1 H]-pyrimidinone dimers (Upy) of Meijer [2], the butylurea of guanosine and 2,7-diamido-1,8-naphtyridine of Zimmerman [13,14], Bouteiller's 2,4-bis(2-ethylhexyl-ureido) toluene [15], Blight's AAAA-DDDD quadruple hydrogen bonding motif [16] also some DNA base analogs [17,18], and the Hamilton wedge/barbituric acid system [19,20]. However, bonding strength is not the only important factor for self-healing ability.…”