Molecular bottlebrush polymer modified magnetic adsorbents with high physicochemical selectivity and unique shape selectivity

A molecular bottlebrush functionalized magnetic adsorbent (magGO@bottlebrush) was fabricated in this work. Poly(hydroxyethyl methacrylate) (PHEMA) was first grafted from polydopamine coated magnetic graphene oxide via surface-initiated atom transfer radical polymerization (SI-ATRP) to produce the backbone of the molecular bottlebrush. Further modification was followed by grafting poly(styrene) via a second SI-ATRP from the PHEMA chains to yield the magGO@bottlebrush. Multiple interactions including hydrophobic, π-π stacking and π-π electron-donor-acceptor interactions greatly contributed to the solute retention. The adsorbent possessed unique shape selectivity, it provided high affinity to non-planar and non-linear compounds. Profiting from densely grafted phenyl and carbonyl groups on the adsorbent, multivalent interactions were exploited to enhance the selectivity for analytes with multiple recognition motifs. Bisphenol A (BPA) was chosen as a model analyte to test real applications of the adsorbent, considering its structural features. The adsorbent owns high adsorption capacity to BPA, and can be readily used for rapid and efficient enrichment of trace BPA from water samples.