Conjugated rod‐coil block copolymers provide an interesting route towards enhancing the properties of the conjugated block due to self‐assembly and the interplay of rod‐rod and rod‐coil interactions. Here, we demonstrate the ability of an attached semi‐fluorinated block to significantly improve upon the charge carrier properties of regioregular poly(3‐hexyl thiophene) (rr‐P3HT) materials on bare SiO2. The thin film hole mobilities on bare SiO2 dielectric surfaces of poly (3‐hexyl thiophene)‐block‐polyfluoromethacrylates (P3HT‐b‐PFMAs) can approach up to 0.12 cm2 V−1 s−1 with only 33 wt% of the P3HT block incorporated in the copolymer, as compared to rr‐P3HT alone which typically has mobilities averaging 0.03 cm2 V−1 s−1. To our knowledge, this is the highest mobility reported in literature for block copolymers containing a P3HT. More importantly, these high hole mobilities are achieved without multistep OTS treatments, argon protection, or post‐annealing conditions. Grazing incidence wide‐angle x‐ray scattering (GIWAX) data revealed that in the P3HT‐b‐PFMA copolymers, the P3HT rod block self‐assembles into highly ordered lamellar structures, similar to that of the rr‐P3HT homopolymer. Grazing incidence small‐angle x‐ray scattering (GISAXS) data revealed that lamellar structures are only observed in perpendicular direction with short PFMA blocks, while lamellae in both perpendicular and parallel directions are observed in polymers with longer PFMA blocks. AFM, GIWAXS, and contact angle measurements also indicate that PFMA block assembles at the polymer thin film surface and forms an encapsulation layer. The high charge carrier mobilities and the hydrophobic surface of the block copolymer films clearly demonstrates the influence of the coil block segment on device performance by balancing the crystallization and microphase separation in the bulk morphological structure.

A novel approach to property enhancement of poly(l-lactic acid) (PLLA) through the use of perfluoropolyether (PFPE) enchainment is described. Segmented copolymers (FluoroPLA) exhibit tailored surface properties with reasonably high molecular weights and low polydispersities compared to PLLA alone using standard ring-opening polymerization procedures in the presence of tin catalysts. Low loadings of PFPE content (ca. 1−5 wt %) decreases surface energies compared to PLLA from 35 to 38 to 15−18 mN/m2, similar to values reported for poly(tetrafluoroethylene). Ultimate strain studies of FluoroPLA fibers and films have shown a dramatic increase (>300% elongation) over PLLA. This new class of polymer may further expand the use of renewable resources in a variety of applications such as flame retardants, chemical resistant fibers and/or fabrics with tailorable surface energies and wetting properties.

In situ copolyesters containing polylactide (PLA) and polyhydroxyalkanoate (PHA) segments were obtained via ring-opening polymerization of L-lactide using PHA as a macroinitiator with stannous octoate as catalyst. Incorporation of PHA (20 wt %) into PLA affords a novel copolymer with Mn values ranging from 25 to 50 KDa and low polydispersities of 1.8-2.3. DSC analysis of the copolymer indicates well-defined crystallization and melting transitions different from the homopolymers and corresponding blend. The polymers were characterized by FT-IR, GPC, DSC, optical microscopy, NMR, and TGA. The results show successful reactivity of PHA as a macroinitiator for the ring-opening polymerization of lactide.

Laboratory-scale synthesis and morphological and surface energy characterization of triblock A-B-A copolymers based on poly(lactic acid) (PLA; A segment) containing various block lengths of perfluoropolyether (PFPE; B segment) at 5 wt% PFPE content are reported. Incorporation of PFPE segments in PLA lowers significantly both the polar and dispersive components of total surface energy. Total surface energy is lowered from ca 35 to ca 17 mN m −1 on copolymerization of PLA with 5 wt% PFPE. Thermal analysis data reveal that lower molecular weight PFPE segments lower significantly the glass transition, crystallization and melting temperatures of the PLA matrix. Although block length variation of the PFPE segment does not affect surface energies of copolymer films, smaller PFPE segments increase significantly the low-temperature modulus as observed from dynamic mechanical analysis.

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