The crystallinity of polymers strongly affects their properties. For block copolymers, whereby two crystallisable blocks are covalently tethered to one another, the molecular weight of the individual blocks and their relative weight fraction are important structural parameters that control their crystallisation. In the case of block copolymer micelles, these parameters can influence the crystallinity of the core, which has implications for drug encapsulation and release. Therefore, in this study, we aimed to determine how the microstructure of poly(ethylene glycol-b-caprolactone) (PEG-b-PCL) copolymers contributes to the crystallinity of their hydrophobic PCL micelle cores. Using a library of PEG-b-PCL copolymers with PEG number-average molecular weight (M_n) values of 2, 5, and 10 kDa and weight fractions of PCL (f_PCL) ranging from 0.11 to 0.67, the thermal behaviour and morphology were studied in blends, bulk, and micelles using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD), and Synchrotron wide-angle X-ray scattering (WAXS). Compared to PEG and PCL homopolymers, the block copolymers displayed reduced crystallinity in the bulk phase and the individual blocks had a large influence on the crystallisation of one another. The f_PCL was determined to be the dominant contributor to the extent and order of crystallisation of the two blocks. When f_PCL < 0.35, the initial crystallisation of PEG led to an amorphous PCL phase. At f_PCL values between 0.35 and 0.65, PEG crystallisation was followed by PCL crystallisation, whereas this behaviour was reversed when f_PCL > 0.65. For lyophilised PEG-b-PCL micelles, the crystallinity of the core increased with increasing f_PCL, although the core was predominately amorphous for micelles with f_PCL < 0.35. These findings contribute to understanding the relationships between copolymer microstructure and micelle core crystallinity that are important for the design and performance of micellar drug delivery systems, and the broader application of polymer micelles.

The inclusion complexation capabilities of cyclodextrins permit them to mediate the adsorption of hydrophobic molecules. Though often associated with pharmaceutical formulations these properties afford a capacity for the extraction of appropriate hydrophobic guest molecules within industrial processes, such as water reclamation from frother contamination within mineral flotation circuits. Industrially applied flotation frothers largely comprise of a mixture of aliphatic alcohols, many of which are known to form stable inclusion complexes with beta-cyclodextrin (β-CD). Cross-linking of β-CD with epichlorohydrin through an emulsion polymerization process, afforded water-insoluble β–CD polymer particles as an effective adsorbent material for frother sequestration. Herein the capacity of these particles to adsorb frother molecules from aqueous solutions is presented. The composition of the industrially relevant frother Interfloat™ F326N, used predominantly for copper-sulfide ore flotation, was firstly elucidated using gas chromatography mass spectrometry. These identified components were then shown to be adsorbed by the β-CD polymer particles, demonstrating the successful sequestration of specific frother molecules from aqueous solution. The results of this study indicate that filtration media based on water-insoluble β-CD polymer particles may provide a viable means of removing frother contamination from recycled process waters. Further, this filtration media may find use in other water purification applications where contamination with organic molecules is of concern.