Surface Segregation of Fluorinated Moieties on Random Copolymer Films Controlled by Random-Coil Conformation of Polymer Chains in Solution

Langmuir ◽  
2009 ◽  
Vol 25 (4) ◽  
pp. 2248-2257 ◽  
Author(s):  
Dongwu Xue ◽  
Xinping Wang ◽  
Huagang Ni ◽  
Wei Zhang ◽  
Gi Xue
Keyword(s):  
Surface Segregation ◽  
Random Copolymer ◽  
Polymer Chains ◽  
Random Coil ◽  
Copolymer Films

pH-Responsive Random Copolymer Films with Amine Side Chains

2007 ◽  
Vol 111 (1) ◽  
pp. 461-466 ◽  
Author(s):  
Dongshun Bai ◽  
Zulkifli Ibrahim ◽  
G. Kane Jennings
Keyword(s):  
Random Copolymer ◽  
Side Chains ◽  
Ph Responsive ◽  
Copolymer Films

Ordered Diblock Copolymer Films on Random Copolymer Brushes

1997 ◽  
Vol 30 (22) ◽  
pp. 6810-6813 ◽  
Author(s):  
P. Mansky ◽  
T. P. Russell ◽  
C. J. Hawker ◽  
M. Pitsikalis ◽  
J. Mays
Keyword(s):  
Diblock Copolymer ◽  
Random Copolymer ◽  
Copolymer Films ◽  
Copolymer Brushes

scholarly journals Temperature-Controlled Solvent Vapor Annealing of Thin Block Copolymer Films

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1312 ◽  
Author(s):  
Xiao Cheng ◽  
Alexander Böker ◽  
Larisa Tsarkova
Keyword(s):  
Thin Films ◽  
Block Copolymer ◽  
Thermal Annealing ◽  
Saturated Vapor ◽  
Polymer Chains ◽  
Special Focus ◽  
Solvent Vapor ◽  
Copolymer Films ◽  
Vapor Annealing ◽  
Solvent Vapor Annealing

Solvent vapor annealing is as an effective and versatile alternative to thermal annealing to equilibrate and control the assembly of polymer chains in thin films. Here, we present scientific and practical aspects of the solvent vapor annealing method, including the discussion of such factors as non-equilibrium conformational states and chain dynamics in thin films in the presence of solvent. Homopolymer and block copolymer films have been used in model studies to evaluate the robustness and the reproducibility of the solvent vapor processing, as well as to assess polymer-solvent interactions under confinement. Advantages of utilizing a well-controlled solvent vapor environment, including practically interesting regimes of weakly saturated vapor leading to poorly swollen states, are discussed. Special focus is given to dual temperature control over the set-up instrumentation and to the potential of solvo-thermal annealing. The evaluated insights into annealing dynamics derived from the studies on block copolymer films can be applied to improve the processing of thin films of crystalline and conjugated polymers as well as polymer composite in confined geometries.

scholarly journals Interface Characteristics of Neat Melts and Binary Mixtures of Polyethylenes from Atomistic Molecular Dynamics Simulations

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1059
Author(s):  
Sanghun Lee ◽  
Curtis W. Frank ◽  
Do Y. Yoon
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Molecular Dynamics Simulations ◽  
Binary Mixtures ◽  
Surface Segregation ◽  
Surface Region ◽  
Polymer Chains ◽  
Methyl Groups ◽  
Free Standing ◽  
Dynamics Simulations

Molecular dynamics simulations of free-standing thin films of neat melts of polyethylene (PE) chains up to C150H302 and their binary mixtures with n-C13H28 are performed employing a united atom model. We estimate the surface tension values of PE melts from the atomic virial tensor over a range of temperatures, which are in good agreement with experimental results. Compared with short n-alkane systems, there is an enhanced surface segregation of methyl chain ends in longer PE chains. Moreover, the methyl groups become more segregated in the surface region with decreasing temperature, leading to the conclusion that the surface-segregation of methyl chain ends mainly arises from the enthalpic origin attributed to the lower cohesive energy density of terminal methyl groups. In the mixtures of two different chain lengths, the shorter chains are more likely to be found in the surface region, and this molecular segregation in moderately asymmetric mixtures in the chain length (C13H28 + C44H90) is dominated by the enthalpic effect of methyl chain ends. Such molecular segregation is further enhanced and dominated by the entropic effect of conformational constraints in the surface for the highly asymmetric mixtures containing long polymer chains (C13H28 + C150H3020). The estimated surface tension values of the mixtures are consistent with the observed molecular segregation characteristics. Despite this molecular segregation, the normalized density of methyl chain ends of the longer chain is more strongly enhanced, as compared with the all-segment density of the longer chain itself, in the surface region of melt mixtures. In addition, the molecular segregation results in higher order parameter of the shorter-chain segments at the surface and deeper persistence of surface-induced segmental order into the film for the longer chains, as compared with those in neat melt films.

scholarly journals Complex Temperature and Concentration Dependent Self-Assembly of Poly(2-oxazoline) Block Copolymers

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1495 ◽  
Author(s):  
Loan Trinh Che ◽  
Marianne Hiorth ◽  
Richard Hoogenboom ◽  
Anna-Lena Kjøniksen
Keyword(s):  
High Temperatures ◽  
Self Assembly ◽  
Low Temperatures ◽  
Polymer Concentration ◽  
Random Copolymer ◽  
Polymer Chains ◽  
Relaxation Modes ◽  
Self Association ◽  
Copolymer Structure ◽  
Complex Temperature

The effect of polymer concentration on the temperature-induced self-association of a block copolymer comprising a poly(2-ethyl-2-oxazoline) block and a random copolymer block consisting of 2-ethyl-2-oxazoline and 2-n-propyl-2-oxazoline (PEtO80-block-P(EtOxx-stat-PropO40-x) with x = 0, 4, or 8 were investigated by dynamic light scattering (DLS) and transmittance measurements (turbidimetry). The polymers reveal a complex aggregation behavior with up to three relaxation modes in the DLS data and with a transmittance that first goes through a minimum before it declines at high temperatures. At low temperatures, unassociated polymer chains were found to co-exist with larger aggregates. As the temperature is increased, enhanced association and contraction of the aggregates results in a drop of the transmittance values. The aggregates fragment into smaller micellar-like clusters when the temperature is raised further, causing the samples to become optically clear again. At high temperatures, the polymers aggregate into large compact clusters, and the samples become turbid. Interestingly, very large aggregates were observed at low temperatures when the polymer concentrations were low. The formation of these aggregates was also promoted by a more hydrophilic copolymer structure. The formation of large aggregates with an open structure at conditions where the solvent conditions are improved is probably caused by depletion flocculation of the smaller aggregates.

A lattice model for the surface segregation of polymer chains due to molecular weight effects

1990 ◽  
Vol 23 (15) ◽  
pp. 3584-3592 ◽  
Author(s):  
Arvind Hariharan ◽  
Sanat K. Kumar ◽  
Thomas P. Russell
Keyword(s):  
Molecular Weight ◽  
Lattice Model ◽  
Surface Segregation ◽  
Polymer Chains
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