BULK AND SOLUTION PROPERTIES OF PEPTIDE-POLYMER CONJUGATES - Biologically-Responsive Hybrid Biomaterials - page 12

(a) (b) (c)

Fig. 6. (a) SAXS and (b) WAXS Patterns for a PFS- b -PZLys film. (c) schematic representation of
HL morphology for PFS-b-PZLys (not to scale). Helices are presented as rods. Adapted from [32].

Diblock copolypeptides

A step forward in the design of hierarchically ordered structures with bio-
functionality has been the recent reports on the synthesis of block copolymers
based on polypeptides. Despite important synthetic efforts, the solid-state
morphology of purely peptidic block copolymers remains largely unexplored.
Hadjichristidis et al. [31] investigated recently the self-assembly of a series of
narrow polydispersity poly( ȳ -benzyl L -glutamate)- block -poly( L -glycine) (PBLG-
b -PLGly) diblock copolymer within the composition range 0.67 < f PBLG < 0.97
and the temperature range 303 < T < 433 K. SAXS, WAXS, 13 C NMR and DSC
were used for the structure investigation coupled with dielectric spectroscopy for
both the peptide secondary structure and the associated dynamics. Not only did
these techniques provide insight into the nanophase morphology, but they also
gave information about the type and persistence of peptide secondary structures.
Hexagonal-in-lamellar and cylinder-on-hexagonal nanostructures have been
especially evidenced. In addition, nanoscale confinement proves to be important
in controlling the persistence length of secondary peptide motifs.

Miscellaneous

Recently, the enhanced control of bulk and surface ordering of polypeptides has
been employed to drive the processing and self-assembly of conductive rigid
segments. Mainly triblock copolymer structures have been studied (see the
following section). Manners and Winnik [ 32 ] synthesized a new type of
metallopolymer-polypeptide block copolymer poly(ferrocenyldimethylsilane)- b -