Description:
<jats:title>Abstract</jats:title><jats:p><jats:sup>13</jats:sup>C‐CP/MAS‐NMR (<jats:italic>c</jats:italic>ross‐<jats:italic>p</jats:italic>olarization <jats:italic>m</jats:italic>agic <jats:italic>a</jats:italic>ngle <jats:italic>s</jats:italic>pinning), 2D‐WISE (<jats:italic>wi</jats:italic>deline <jats:italic>se</jats:italic>paration experiment) and <jats:sup>1</jats:sup>H‐spin diffusion experiments allow to gain new insight into the structure and dynamics of solid polyelectrolyte‐surfactant complexes, a material with pronounced mesophase formation. Experiments were performed on two different complexes of polystyrene sulfonate and octadecyltrimethylammonium or tetradecyltrimethylammonium counterions, PSS‐C<jats:sub>18</jats:sub> and PSS‐C<jats:sub>14</jats:sub>. The strong mobility differences between the ionic and alkyl phase in the lamellar complex PSS‐C<jats:sub>18</jats:sub> are reflected in the NMR behavior: in the surfactant tails, a mobility gradient towards the terminal methyl group is observed. This fact as well as a high content of <jats:italic>gauche</jats:italic> conformations suggest a non‐interdigitating morphology of the tails at room temperature. The behavior changes during cooling below an endothermic transition centered at 255 K where a high <jats:italic>trans</jats:italic> content and a homogenization of the side chain dynamics is observed. We attribute this transition which is invisible in the X‐ray experiments to the formation of a highly transoid, interdigitated phase of the surfactant tails which is however not crystallized in a classical sense. <jats:sup>1</jats:sup>H‐spin diffusion experiments allow to estimate the distance between mobile and immobile regions of the sample. For the complex PSS‐C<jats:sub>14</jats:sub>, the length scale determined by NMR is essentially that of the primary lamellar structure. For PSS‐C<jats:sub>18</jats:sub>, a characteristic length of the density fluctuations within the proposed undulated lamellar structure is estimated.</jats:p>