Related Experiment Video
Updated: May 19, 2026
Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
Micelles of polybutadiene-b-poly(ethylene oxide) in deuterated methanol and deuterated cyclohexane
1Department of Chemistry and Biochemistry, The University of Maryland College Park, College Park, MD 20742, United States. bclover@umd.edu
Abstract:
Micellization of the diblock copolymer poly(ethylene oxide)-b-polybutadiene, PEO(132)-PB(89), where the subscripts denote the number of monomers in each block, has been studied in solution in deuterated methanol and in deuterated cyclohexane, in order to compare the micellar assembly in deuterated solvents to that in protonated solvents. The methods used were dynamic light scattering and small angle neutron scattering. In CD(3)OD, PEO(132)-PB(89) forms only spherical micelles that change little in size or shape over the temperature range 21-68°C. In CH(3)OH, PEO(132)-PB(89) forms coexisting cylindrical and spherical structures over the entire temperature range. Thus cylindrical micelles form in CH(3)OH, but do not form in CD(3)OD. In C(6)D(12), the copolymer forms flexible, cylindrical micelles at lower temperatures; above about 40°C, spherical micelles and free copolymers appear and coexist with the cylindrical micelles. The behavior in C(6)H(12) is the same as in C(6)D(12), except that no free copolymers are observed in C(6)H(12). The stronger hydrogen bonding in deuterated methanol as compared to protonated methanol is assumed to be the source of the difference in assembly.
More Related Videos
10:53Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
09:57A Facile and Efficient Approach for the Production of Reversible Disulfide Cross-linked Micelles
Published on: December 23, 2016
Related Concept Videos
02:30Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
01:24π Molecular Orbitals of 1,3-Butadiene
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
01:30Micelles
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
01:28Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
01:16Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...