posted on 2021-08-18, 19:45authored byHathaithep Senkum, Peter V. Kelly, William M. Gramlich
Well-defined
and densely grafted amphiphilic cationic bottlebrush
block copolymers (BBCPs) containing polystyrene (PS) and quaternary
ammonium polymer (PDMH) side chains, PS-b-PDMH, were
successfully generated from grafting-through ring-opening metathesis
polymerization. The amphiphilic BBCP thin films, analyzed by atomic
force microscopy (AFM), could self-assemble into distinct nanometer-scale
domains of which the morphologies were manipulated by the volume fraction
of the cationic block (fPDMH), degree
of polymerization, and asymmetric block side-chain lengths. The morphological
stability of the BBCP thin films upon water exposure was investigated.
The AFM images of casted BBCP films demonstrated surface roughening
and morphology changes upon submersion as compared to precursor dry
films, which was attributed to the swelling of the cationic domains
and the rearrangement of the alkyl chain pendant groups under water.
Thermally annealed films of PS-b-PDMH with an fPDMH of 0.5 exhibited water-stable surfaces
after water submersion, indicating that the BBCP structure can prevent
some surface rearrangement. Such coatings could be used as potential
antimicrobial and antifouling surfaces in future studies.