Structural Order in Conjugated Organic Films Prepared by Catalytic Deprotection of Self-Assembled Polymers

Abstract

Persistent lamellar ordering, consistent with coplanar stacking of polymer chains, is found for films of poly(3-(2-hydroxylethyl)thiophene) (PHET) obtained by catalytic removal of tetrahydropyran from films of poly(3-(2-(2-tetrahydropyranyloxy)ethyl)thiophene) (PTHPET). Structural ordering appears to be due to H-bonding interactions between terminal hydroxy groups. This morphology is unique for films comprising of short side chain poly(alkylthiophenes), which are usually characterized as being amorphous. The resultant films possess void spaces due to loss of the bulky group and retention of the initial morphology. The formation of additional free volume may explain why this reaction is facile in these materials even though they are semicrystalline. Catalytic removal of tetrahydropyran from copolymer films of PTHPET and 3-hexylthiophene also leads to persistent ordering, but the lamellar framework partially relaxes in some cases so that the interlamellar spacing is reduced. These are metastable structures that become amorphous upon heating to elevated temperatures.

Synthesis, Solid-Phase Reaction, Optical Properties, and Patterning of Luminescent Polyfluorenes

“…The observed weight losses of P1 , P2 , P3 , and P4 are 40, 22, 34, and 39 wt %, consistent with the theoretical weight losses. Only 5 mol % acid is needed to get full deprotection of the THP group, indicating the removal of THP is catalyzed similar to that reported for polythiophenes ).…”

“…THP is a relatively thermally stable protecting group. For example, poly(3-(2-(2-tetrahydropyranyloxy)ethyl)thiophene) (PTHPET) was reported stable up to 220−230 °C. 18a,b For P1 and P4 , a significant loss in mass is observed by TGA above this temperature, as shown in Table . P3 exhibits a lower deprotection temperature, which is ascribed to its lower molecular weight 19a.…”

“…Recently, photochemical cross-linking to produce insoluble polymer networks and laser-induced thermal imaging were successfully used in manufacturing devices. In the context of photolithography and soft lithography, several regioregular polythiophenes containing a 2-tetrahydropyranyl (THP) group were reported recently. , Compared with acid-catalyzed photolithography, the soft lithographic process is a low-cost technique that circumvents the use of expensive lenses and eliminates possible damage to the conjugated polymer structure due to irradiation . In addition, soft lithography can pattern flexible surfaces.…”

Synthesis and Characterization of Poly(methyl acrylate) Grafted from Poly(thiophene) to Form Solid-State Fluorescent Materials

“…Polymer 4 was then deprotected and functionalized into an ATRP macroinitiator. A key aspect in macroinitiator functionalization is that removal of the protecting group and addition of the ATRP initiator must take place in the same step, because the deprotected hydroxy polymer is insoluble in any solvent. , To avoid precipitation of the backbone, 2-bromopropionyl bromide was added in excess before the tetrabutylammonium fluoride cleavage agent, which resulted in the highest degree of functionalization (see Table ).…”

Synthesis and characterization of isocyanate‐functionalized PVA‐based polymers with applications as new additives in lubricant formulations

“…In most cases, the OH groups from the monomers were previously protected and polymerization was accomplished next. For instance, the OHs were protected as tetrahydropyranyl (THP) ethers in the production of a soluble, acid‐labile, blue luminescent fluorene‐based polymer5 and in films of polythiophenes 6. The THP group could also be found in macromolecular initiators as those ones used for the preparation of functionalized polyethylene oxide for click chemistry 7…”