Analyzing the Surface Temperature Depression in Hot Stage Atomic Force Microscopy with Unheated Cantilevers:  Application to the Crystallization of Poly(ethylene oxide)

Langmuir ◽  
2002 ◽  
Vol 18 (2) ◽  
pp. 490-498 ◽  
Author(s):  
Holger Schönherr ◽  
Larry E. Bailey ◽  
Curtis W. Frank
Keyword(s):  
Atomic Force Microscopy ◽  
Ethylene Oxide ◽  
Surface Temperature ◽  
Force Microscopy ◽  
Atomic Force ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Temperature Depression

Atomic Force Microscopy and Light Scattering Study of Onion-Type Micelles Formed by Polystyrene-block-poly(2-vinylpyridine) and Poly(2-vinylpyridine)-block-poly(ethylene oxide) Copolymers in Aqueous Solutions

2006 ◽  
Vol 71 (5) ◽  
pp. 723-738 ◽  
Author(s):  
Pavel Matějíček ◽  
Miroslav Štěpánek ◽  
Mariusz Uchman ◽  
Karel Procházka ◽  
Milena Špírková
Keyword(s):  
Atomic Force Microscopy ◽  
Light Scattering ◽  
Ethylene Oxide ◽  
Self Assembly ◽  
Distribution Functions ◽  
Force Microscopy ◽  
Mass Distributions ◽  
Atomic Force ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

The three-layer onion micelles formed in aqueous solution by hierarchical self-assembly of polystyrene-block-poly(2-vinylpyridine) micelles, PS-PVP, and poly(2-vinylpyridine)-block-poly(ethylene oxide) chains, PVP-PEO, were studied by a combination of light scattering (LS) and atomic force microscopy (AFM). Section analysis of AFM images of micelles deposited on mica in combination with LS data from micellar solutions provide distribution functions of sizes from which the number and mass distributions of molar masses of micelles can be evaluated. Both light scattering and AFM data reveal that the used preparation protocol yields onion micelles accompanied by an admixture of PVP-PEO micelles. It means that only a certain amount of PVP-PEO self-assembles with PS-PVP and forms onion micelles. The remaining PVP-PEO copolymer forms either small PVP-PEO micelles or participates in formation of large aggregates at longer times. The time-dependent measurements show that both onion-type and core-shell PVP-PEO micelles are fairly stable over a long time period and only a low fraction of large aggregate forms on the timescale of weeks and at longer times, the solution does not change any more.

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