A photoresponsive
nanoporous polymer film has been produced from
the templated self-assembly of a columnar liquid crystal containing
azo units. A liquid crystalline complex of polymerizable azobenzoic
acid and a tris-benzimidazolyl benzene template molecule was cross-linked
via thiol-ene radical copolymerization with dodecanedithiol. Subsequent
removal of the template yielded nanoporous polymer films with pores
of approximately 1 nm in diameter. Both trans–cis and cis–trans
photoisomerizations of azobenzoic acid took place in the porous films.
At room temperature, the cis isomer was sufficiently long-lived to
establish a difference in dye absorption kinetics of the two isomers.
The cationic dye rhodamine 6G was bound to both isomers, but the rate
of binding to films enriched in the cis isomer was 8 times faster.
High molar mass polycarbonate is synthesized via a solution transcarbonation of bis(methyl salicyl) carbonate and bisphenol‐A at temperatures between 60 and 160 °C without the removal of the condensate, allowing the incorporation of thermosensitive monomers into polycarbonate. Kinetic and equilibrium studies show that the polymerization is 20–30 times faster at 120 °C compared to 60 °C, whereas the equilibrium Mw increases from 11 × 103 g mol−1 at 120 °C to 16 × 103 g mol−1 at 60 °C. This polycondensation is characterized by very high equilibrium constants ranging from 0.8 × 103 at 160 °C to 4.1 × 103 at 60 °C, corresponding to standard enthalpies and entropies of polymerization: −19 kJ mol−1 < ΔH0 < −11 kJ mol−1 and 13 J mol−1 K−1 < ΔS0 < 28 J mol−1 K−1. Without removal of the condensate, the system is shown to be dynamic and completely reversible when changing the temperature. Good predictability of this polycondensation is reported, where only at very low starting monomer concentrations, the formation of cyclics leads to deviations from the predicted behavior.
The exploration of new materials is timeless. Especially 2D-materials have gotten much interest in the last decades. This work proposes a new route towards a fascinating class of 2D materials: molecular textiles. The suggested bottom-up approach focuses on the 2D self-assembly of a cross-shaped monomer at the water/air interface. A 3D cross-shaped motive was designed, synthesized, and characterized, which exhibits the required structural features, i. e., static and dynamic control. Analysis of the cross-shaped motive by 1 H-NMR spectroscopy, X-ray structure, and chiral stationary phase HPLC proved the rigidity and stability of the system, and thus also its potential for the here suggested new strategy towards molecular textiles. Three variants of a Schiff-base precursor pair functionalized monomer were synthesized and characterized by 1 H-NMR spectroscopy, 13 C-NMR spectroscopy, and mass spectrometry. Finally, the network formation of the monomer is shown to be triggered by deprotonation of its ammonium salt, corroborated with FT-IR analysis.
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