Tuning Surface Properties of Poly(methyl methacrylate) Film Using Poly(perfluoromethyl methacrylate)s with Short Perfluorinated Side Chains

To control the surface properties of a commonly used polymer, poly­(methyl methacrylate) (PMMA), poly­(perfluoromethyl methacrylate)­s (PFMMAs) with short perfluorinated side groups (i.e., −CF₃, −CF₂CF₃, −(CF₃)₂, −CF₂CF₂CF₃) were used as blend components because of their good solubility in organic solvents, low surface energies, and high optical transmittance. The surface energies of the blend films of PFMMA with the −CF₃ group and PMMA increased continuously with increasing PMMA contents from 17.6 to 26.0 mN/m, whereas those of the other polymer blend films remained at very low levels (10.2–12.6 mN/m), similar to those of pure PFMMAs, even when the blends contained 90 wt %PMMA. Surface morphology and composition measurements revealed that this result originated from the different blend structures, such as lateral and vertical phase separations. We expect that these PFMMAs will be useful in widening the applicable window of PMMA

Improved Field-Effect Transistor Performance of a Benzotrithiophene Polymer through Ketal Cleavage in the Solid State

A benzotrithiophene polymer with a new thermally cleavable ketal substituent is reported. It is shown how this functional group can be used to facilitate solvent processing and, subsequently, how it can be removed by a thermal annealing process to generate a structurally ordered and crystalline thin film with significantly improved field-effect transistor properties

Isostructural, Deeper Highest Occupied Molecular Orbital Analogues of Poly(3-hexylthiophene) for High-Open Circuit Voltage Organic Solar Cells

We present the synthesis and characterization of two novel thiazole-containing conjugated polymers (<b>PTTTz</b> and <b>PTTz</b>) that are isostructural to poly­(3-hexylthiophene) (P3HT). The novel materials demonstrate optical and morphological properties almost identical to those of P3HT but with HOMO and LUMO levels that are up to 0.45 eV deeper. An intramolecular planarizing nitrogen–sulfur nonbonding interaction is observed, and its magnitude and origin are discussed. Both materials demonstrate significantly greater open circuit voltages than P3HT in bulk heterojunction solar cells. <b>PTTTz</b> is shown to be an extremely versatile donor polymer that can be used with a wide variety of fullerene acceptors with device efficiencies of up to 4.5%. It is anticipated that this material could be used as a high-open circuit voltage alternative to P3HT in organic solar cells