A novel, highly selective photocyclic aromatization (SCAT) of π-conjugated polymers from phenylacetylene having two hydroxyl groups to exclusively yield a 1,3,5-trisubstituted benzene derivative was developed, and its success was confirmed by (1)H NMR, GPC, and TOF-MS. The SCAT reaction has many unique characteristics. (1) It is a quantitative reaction: it gave only the corresponding cyclic trimer, i.e., a 1,3,5-trisubstituted benzene derivative, quantitatively (100%). No byproducts were produced under the best conditions. (2) It is an intramolecular reaction: it occurred between three adjacent monomer units in one macromolecule. (3) It is a stereospecific and topochemical or template reaction: the reactivity strongly depended on the configuration and conformation of the starting polymer substrates. (4) It is a photoreaction: high selectivity (100%) was observed only by the use of visible light irradiation, not by heating. (5) It is a solid-state reaction: high selectivity (100%) was observed only in the solid state, not in solution. In addition, (6) the resulting cyclic trimers could form a self-supporting membrane, despite their low molecular weights. This new approach resulted in a new class of supramolecular polymers consisting of a 1,3,5-trisubstituted benzene derivative, numbers of which were linearly linked by hydrogen bonds and stacked benzene derivatives. Since SCAT has such high selectivities and is useful for the preparation of a self-supporting supramolecular polymer membrane, many applications can be expected.

Two new chiral helical poly(hydroxyl-containing phenylacetylene) membranes without the coexistence of any other chiral moieties were prepared in the following manner:  (1) synthesis and homo- or copolymerization of two new chiral pinanylsiloxy-containing phenylacetylenes, (2) preparation of self-supporting membranes from the (co)poly(chiral pinanylsiloxy-containing phenylacetylene)s by a solvent-casting technique, and (3) depinanylsilylation of the preformed polymer membranes in situ. Complete depinanylsilylation was successfully achieved by treating with trifluoroacetic acid. The resulting membranes exhibited circular dichroism despite the absence of the chiral substituents, a fact indicating that the main chains of the polymers retained their chiral helicity. This is the first method to synthesizing such chiral poly(phenylacetylene) membranes. Since the membranes maintained their self-supporting properties, we were able to use them as enantioselective separation membranes in the permeation of an aqueous solution of a racemate. As a result, the importance of the contribution of the chiral main chain on enantioselective permeation was directly confirmed for the first time. In addition, since some of the depinanylsilylated membranes were insoluble in organic solvents, we could use them as an separation membrane for a toluene solution of a racemate.

A series of amphiphilic liquid crystalline diblock copolymers, PEO m -b-PMA(Az) n , consisting of hydrophilic poly(ethylene oxide) and hydrophobic poly(methacrylate) moieties with side chains containing liquid crystalline (LC) azobenzene moieties, produced highly ordered microphaseseparated films with PEO cylinders aligned perpendicular to the smectic LC layer of azobenzene in the PMA(Az) matrix. In this paper, morphological phase diagrams of PEO m -b-PMA(Az) n diblock copolymers above and below the isotropic transition temperature of LC azobenzene (T iso ) are presented. The diagrams are based on small-angle X-ray scattering (SAXS) measurements of approximately 70 kinds of polymers with varying degrees of polymerization in each block. An asymmetric phase diagram described against the volume fraction of PEO ( f PEO ) was obtained at temperatures above and below T iso . The lamellar phase appears in the f PEO window 0.52 ≤ f PEO ≤ 0.78 above and below T iso . Besides, the wide window, 0.087 ≤ f PEO < 0.52, allows the PEO cylinder phase to form below T iso . In particular, the PEO sphere phase, observed above T iso , was completely eliminated through an order− order transition (OOT) to the PEO cylinder phase in the window 0.087 ≤ f PEO ≤ 0.23. Such a large expansion in the PEOcylinder-phase window could be attributed to the main chain of LC PMA(Az) being shorter than that of the flexible PEO chain, and LC azobenzene forming a smectic layer in the microphase separated system.

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