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Tuning the Chirality of Block Copolymers: From Twisted Morphologies to Nanospheres by Self‐Assembly
Author(s) -
SuárezSuárez Silvia,
Carriedo Gabino A.,
Soto Alejandro Presa
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501705
Subject(s) - chirality (physics) , helicity , copolymer , self assembly , block (permutation group theory) , circular dichroism , materials science , nanostructure , stereochemistry , crystallography , chemistry , nanotechnology , physics , organic chemistry , polymer , combinatorics , chiral symmetry , mathematics , particle physics , quantum mechanics , nambu–jona lasinio model , quark
New advances into the chirality effect in the self‐assembly of block copolymers (BCPs) have been achieved by tuning the helicity of the chiral‐core‐forming blocks. The chiral BCPs {[NP( R )‐O 2 C 20 H 12 ] 200− x [NP(OC 5 H 4 N) 2 ] x }‐ b ‐ [NPMePh] 50 (( R )‐O 2 C 20 H 12 =( R )‐1,1′‐binaphthyl‐2,2′‐dioxy, OC 5 H 4 N=4‐pyridinoxy (OPy); x =10, 30, 60, 100 for 3 a – d , respectively), in which the [NP(OPy) 2 ] units are randomly distributed within the chiral block, have been synthesised. The chiroptical properties of the BCPs ([ α ] D vs. T and CD) demonstrated that the helicity of the BCP chains may be simply controlled by the relative proportion of the chiral and achiral (i.e., [NP( R )‐O 2 C 20 H 12 ] and [NP(OPy) 2 ], respectively) units. Thus, although 3 a only contained only 5 % [NP(OPy) 2 ] units and exhibited a preferential helical sense, 3 d with 50 % of this unit adopted non‐preferred helical conformations. This gradual variation of the helicity allowed us to examine the chirality effect on the self‐assembly of chiral and helical BCPs (i.e., 3 a – c ) and chiral but non‐helical BCPs (i.e., 3 d ). The very significant influence of the helicity on the self‐assembly of these materials resulted in a variety of morphologies that extend from helical nanostructures to pearl‐necklace aggregates and nanospheres (i.e., 3 b and 3 d , respectively). We also demonstrate that the presence of pyridine moieties in BCPs 3 a – d allows specific decoration with gold nanoparticles.