1 research outputs found
Elucidation of Novel Nanostructures by Time-Lapse Monitoring of Polystyrene-<i>block</i>-Polyvinylpyridine under Chemical Treatment
Nanoscale micellar structures of polystyrene-<i>block</i>-polyvinylpyridine (PS-<i>b</i>-PVP) diblock
copolymers
have proven their effectiveness in lithography and biological detection
by serving as a choice material to produce nanoscale guides and delivery
systems in a straightforward and rapid manner through self-assembly.
Such applications can greatly benefit from having high versatility
for the selection of template sizes (pattern repeat spacing) and shapes
(pattern geometry), especially when reaching a size regime that conventional
top-down fabrication techniques may not readily be able to provide
desired feature dimensions. Selective chemical treatments of the diblock
copolymers are one of the useful methods yielding a rich set of nanoscale
features on PS-<i>b</i>-PVP. Exposure to selective vapor
can induce reorganization of the polymeric chains of PS-<i>b</i>-PVP and alter the original micellar nanostructures. In this Article,
we identify for the first time a host of new nanostructures formed
at different stages of chloroform vapor annealing by performing time-lapse
atomic force microscopy measurements. We determine key, time-dependent,
topological parameters defining each nanostructure and present the
likely scenario of polymeric chain reorganization during the morphological
evolution of the diblock polymer nanodomains over time. We also ascertain
intermediate morphological states containing the characteristic nanostructures
from two consecutive phases as well as transition states appearing
for a short time in between two subsequent phases. These research
efforts may not only provide insight into the domain evolution steps
of the micellar to the cylindrical structures of PS-<i>b</i>-PVP but may also be technologically advantageous for subwavelength
mask design in nanolithography and high-density array fabrication
in high throughput biodetection