2 research outputs found
Pathway toward Large Two-Dimensional Hexagonally Patterned Colloidal Nanosheets in Solution
We report the solution
self-assembly of an ABC block terpolymer
consisting of a polystyrene-<i>block</i>-polyÂ(ethylene oxide)
(PS-<i>b</i>-PEO) diblock copolymer tail tethered to a fluorinated
polyhedral oligomeric silsesquioxane (FPOSS) cage in 1,4-dioxane/water.
With increasing water content, abundant unconventional morphologies,
including circular cylinders, two-dimensional hexagonally patterned
colloidal nanosheets, and laterally patterned vesicles, are sequentially
observed. The formation of toroids is dominated by two competing free
energies: the end-cap energy of cylinders and the bending energy to
form the circular structures. Incorporating the superhydrophobic FPOSS
cages enhances the end-cap energy and promotes toroid formation. Lateral
aggregation and fusion of the cylinders results in primitive nanosheets
that are stabilized by the thicker rims to partially release the rim-cap
energy. Rearrangement of the parallel-aligned FPOSS cylindrical cores
generates hexagonally patterned nanosheets. Further increasing the
water content induces the formation of vesicles with nanopatterned
walls
Structurally Defined Nanoscale Sheets from Self-Assembly of Collagen-Mimetic Peptides
We report the design of two collagen-mimetic
peptide sequences, <b>NSI</b> and <b>NSII</b>, that self-assemble
into structurally
defined nanoscale sheets. The underlying structure of these nanosheets
can be understood in terms of the layered packing of collagen triple
helices in two dimensions. These nanosheet assemblies represent a
novel morphology for collagen-based materials, which, on the basis
of their defined structure, may be envisioned as potentially biocompatible
platforms for controlled presentation of chemical functionality at
the nanoscale. The molecularly programmed self-assembly of peptides <b>NSI</b> and <b>NSII</b> into nanosheets suggests that sequence-specific
macromolecules offer significant promise as design elements for two-dimensional
(2D) assemblies. This investigation provides a design rubric for fabrication
of structurally defined, peptide-based nanosheets using the principles
of solution-based self-assembly facilitated through complementary
electrostatic interactions