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The conductivity and charge transport mobility of conjugated polymers (CPs) are largely correlated with their degree of crystallinity, rendering the crystallization of CPs an important endeavour. However, such tasks can be challenging, especially in the absence of sidechain functionalization. In this study, we demonstrate that the incorporation of a small amount of oligomers, specifically tetraaniline, can induce crystallization of the parent polymer, polyaniline, through a single-step self-assembly process. The resulting crystals are compositionally homogeneous because the oligomers and their parent polymer share the same repeating unit and are both electroactive. Mechanistic studies reveal that the tetraaniline forms a crystalline seed that subsequently guides the assembly of polyaniline due to their structural similarities. Applying this oligomer-assisted crystallization approach to polyaniline with defined molecular weights resulted in single crystalline nanowires for 5000 Da polyaniline, and nanowires with strong preferential chain orientation for those with molecular weights between 10 000 and 100 000 Da. Absorption studies reveal that the polymer chains are in an expanded conformation, which likely contributed to the high degree of packing order. Two-probe, single nanowire measurements show that the crystals have conductivity as high as 19.5 S cm −1 . This method is simple, general, and can potentially be applied tomore »other CPs.« less

Plants will experience considerable changes in climate within their geographic ranges over the next several decades. They may respond by exhibiting niche flexibility and adapting to changing climates. Alternatively, plant taxa may exhibit climate fidelity, shifting their geographic distributions to track their preferred climates. Here, we examine the responses of plant taxa to changing climates over the past 18,000 y to evaluate the extent to which the 16 dominant plant taxa of North America have exhibited climate fidelity. We find that 75% of plant taxa consistently exhibit climate fidelity over the past 18,000 y, even during the times of most extreme climate change. Of the four taxa that do not consistently exhibit climate fidelity, three—elm ( Ulmus ), beech ( Fagus ), and ash ( Fraxinus )—experience a long-term shift in their realized climatic niche between the early Holocene and present day. Plant taxa that migrate longer distances better maintain consistent climatic niches across transition periods during times of the most extreme climate change. Today, plant communities with the highest climate fidelity are found in regions with high topographic and microclimate heterogeneity that are expected to exhibit high climate resilience, allowing plants to shift distributions locally and adjust to somemore »amount of climate change. However, once the climate change buffering of the region is exceeded, these plant communities will need to track climates across broader landscapes but be challenged to do so because of the low habitat connectivity of the regions.« less