Synchrotron X-Ray Analysis and Morphology Evidence for Stereo-Assemblies of Periodic Aggregates in Poly(3-Hydroxybutyrate) with Unusual Photonic Iridescence

Abstract

Y.-H. Liao, S. Nagarajan, E. M. Woo, W.-T. Chuang, and Y.-W. Tsai, “Synchrotron X-Ray Analysis and Morphology Evidence for Stereo-Assemblies of Periodic Aggregates in Poly(3-Hydroxybutyrate) With Unusual Photonic Iridescence,” Macromolecular Rapid Communications 42, no. 14 (2021): 2100281, https://doi.org/10.1002/marc.202100281.

The authors would like to note that, in Figure 3b, the y-axis was mislabeled as “Band spacing” instead of the correct label, “Growth Rates (µm/min).”

We would like to clarify that Figure S3 (Supporting Information), which was published alongside the main paper as part of the Supporting Information, includes the same two panels: Figure S3a (Supporting Information) shows band spacing versus crystallization temperature (T_c), and Figure S3b (Supporting Information) presents growth rate versus T_c with the y-axis correctly labeled as “Growth rate (µm/s).” This figure covers data from PHB/PEO (75/25) blend spherulites crystallized at T_c = 30, 45, 50, 70, and 80 °C.

The updated Figure 3 is included as follows to ensure consistency with SI units and to replace the previously mislabeled version.

The authors would also like to introduce the following additional clarifications and corrections to the text:

Figures 1e and 4–Spiral spin direction: The direction of spiral band rotation (i.e., clockwise or counterclockwise) is not uniform across the sample but depends on the local nucleation site orientation and location of nucleation in the film layer. As a result, different spherulites—or even regions within the same spherulite—can exhibit varied spiral senses. This sample-dependent variability explains why Figures 1e and 4 show opposite spin directions; each image captures a different nucleus with its own local orientation.

Figure 3a–Band spacing maximum: The original text referred to 43 °C as the point of maximum band spacing. However, Figure 3a shows that the band spacing of the PHB/PTA (75/25) blend increases with increasing T_c, reaching a maximum of ≈45 µm at T_c ≈ 43–45 °C, but this point is hard to define precisely. Beyond this temperature—around T_c ≈ 45 °C—the bands broaden significantly and lose definition, appearing to ‘disappear’.

Figures 12b and 13–Labelling inconsistency: Figure 12b shows a scan across five points—Ridge (a), Valley (b), Ridge (c), Valley (d), Ridge (e). By contrast, Figure 13 presents a separate, shorter scan consisting of four points: Valley (a), Ridge (b), Valley (c), Ridge (d). The authors wish to note that this apparent inconsistency is due to the different scan ranges and point counts, not due to a conflict in the data.

We apologize for these errors.