ISSN:
0947-6539
Keywords:
amphiphiles
;
block copolymers
;
dendrimers
;
micelles
;
surfactants
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A new class of amphiphilic macromolecules has successfully been synthesized by creating well-defined diblock copolymers of polystyrene (PS, Mn=3.2 × 103, Mw/Mn=1.04) with poly-(propylene imine) dendrimers. A poly-styrene core molecule with a primary amine end-group was prepared by a quantitative three-step modification procedure of acid-functionalized polystyrene. On this core molecule, five different generations from PS-dendr-NH2 up to PS-dendr-(NH2)32 were constructed in high yields. The molecular structure of the block co-polymers was analyzed in detail with NMR and IR spectroscopy and electrospray mass spectrometry. With conductivity measurements and monolayer pressure-area isotherm determinations, we observed generation-dependent amphiphilic behavior. Dynamic light scattering and transmission electron microscopy showed that amphiphile geometry had a distinct effect on aggregation behavior; this is in qualitative agreement with Israelachvili's theory. Critical association concentrations determined with the pyrene probe luminescence technique were as low as 5 × 10-7 M. The amphiphiles presented here, therefore, show a resemblance to traditional block copolymers with regard to size and stability, and are similar to surfactants with respect to tuning of the shape.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19960021221
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