scholarly journals Design principles for metamorphic block copolymer assemblies

Soft Matter ◽  
2020 ◽  
Vol 16 (9) ◽  
pp. 2342-2349
Author(s):  
Alessandro Ianiro ◽  
Steven P. Armes ◽  
Remco Tuinier
Keyword(s):  
Block Copolymer ◽  
Design Principles ◽  
Solution Temperature ◽  
Efficient Design ◽  
Selective Solvents ◽  
Dynamic Morphology

Certain block copolymer assemblies in selective solvents undergo dynamic morphology transitions (metamorphism) on varying the solution temperature. We provide theoretical guidelines for an efficient design of these systems.

scholarly journals Scalable Protocols Offer Efficient Design for Field Experiments

2005 ◽  
Vol 13 (3) ◽  
pp. 233-252 ◽  
Author(s):  
David W. Nickerson
Keyword(s):  
External Validity ◽  
Field Experiments ◽  
Design Principles ◽  
Efficient Design ◽  
Controlled Experiments ◽  
Statistical Efficiency ◽  
Voter Mobilization ◽  
Treatment Matching ◽  
The Face ◽  
Scalable Protocols

Experiments conducted in the field allay concerns over external validity but are subject to the pitfalls of fieldwork. This article proves that scalable protocols conserve statistical efficiency in the face of problems implementing the treatment regime. Three designs are considered: randomly ordering the application of the treatment; matching subjects into groups prior to assignment; and placebo-controlled experiments. Three examples taken from voter mobilization field experiments demonstrate the utility of the design principles discussed.

scholarly journals Widely Tunable Morphologies in Block Copolymer Thin Films Through Solvent Vapor Annealing Using Mixtures of Selective Solvents

2015 ◽  
Vol 25 (20) ◽  
pp. 3057-3065 ◽  
Author(s):  
Michelle A. Chavis ◽  
Detlef-M. Smilgies ◽  
Ulrich B. Wiesner ◽  
Christopher K. Ober
Keyword(s):  
Thin Films ◽  
Block Copolymer ◽  
Solvent Vapor ◽  
Selective Solvents ◽  
Vapor Annealing ◽  
Solvent Vapor Annealing

Nanoporous block copolymer films using highly selective solvents and non-solvent extraction

Soft Matter ◽  
2015 ◽  
Vol 11 (43) ◽  
pp. 8499-8507 ◽  
Author(s):  
Changhuai Ye ◽  
Bryan D. Vogt
Keyword(s):  
Optical Properties ◽  
Solvent Extraction ◽  
Block Copolymer ◽  
Porous Film ◽  
Copolymer Films ◽  
Solvent Water ◽  
Rapid Extraction ◽  
Selective Solvents ◽  
Tunable Optical Properties ◽  
Highly Porous

Selective swelling of matrix by alcohol followed by rapid extraction by the non-solvent water leads to a highly porous film with tunable optical properties. These films exhibit anti-reflective properties and are thermally robust.

Anthracene functionalized thermosensitive and UV-crosslinkable polymeric micelles

2015 ◽  
Vol 6 (11) ◽  
pp. 2048-2053 ◽  
Author(s):  
Yang Shi ◽  
Renata M. Cardoso ◽  
Cornelus F. van Nostrum ◽  
Wim E. Hennink
Keyword(s):  
Aqueous Solution ◽  
Block Copolymer ◽  
Lower Critical Solution Temperature ◽  
Polymeric Micelles ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Uv Illumination ◽  
Uv Lamp

An anthracene-functionalized thermosensitive block copolymer was synthesized, which formed micelles by heating its aqueous solution above the lower critical solution temperature (LCST). The micelles were subsequently crosslinked by UV illumination at 365 nm with a normal handheld UV lamp.

scholarly journals Self-Assembly of Molecular Brushes with Polyimide Backbone and Amphiphilic Block Copolymer Side Chains in Selective Solvents

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2922
Author(s):  
Maria Simonova ◽  
Ivan Ivanov ◽  
Tamara Meleshko ◽  
Alexey Kopyshev ◽  
Svetlana Santer ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Methyl Methacrylate ◽  
Self Assembly ◽  
Amphiphilic Block Copolymer ◽  
Side Chains ◽  
Poly Methyl Methacrylate ◽  
Molecular Brushes ◽  
Selective Solvents ◽  
Significant Difference ◽  
Thermodynamic Quality

Three-component molecular brushes with a polyimide backbone and amphiphilic block copolymer side chains with different contents of the “inner” hydrophilic (poly(methacrylic acid)) and “outer” hydrophobic (poly(methyl methacrylate)) blocks were synthesized and characterized by molecular hydrodynamics and optics methods in solutions of chloroform, dimethylformamide, tetrahydrofuran and ethanol. The peculiarity of the studied polymers is the amphiphilic structure of the grafted chains. The molar masses of the molecular brushes were determined by static and dynamic light scattering in chloroform in which polymers form molecularly disperse solutions. Spontaneous self-assembly of macromolecules was detected in dimethylformamide, tetrahydrofuran and ethanol. The aggregates size depended on the thermodynamic quality of the solvent as well as on the macromolecular architectural parameters. In dimethylformamide and tetrahydrofuran, the distribution of hydrodynamic radii of aggregates was bimodal, while in ethanol, it was unimodal. Moreover, in ethanol, an increase in the poly(methyl methacrylate) content caused a decrease in the hydrodynamic radius of aggregates. A significant difference in the nature of the blocks included in the brushes determines the selectivity of the used solvents, since their thermodynamic quality with respect to the blocks is different. The macromolecules of the studied graft copolymers tend to self-organization in selective solvents with formation of a core–shell structure with an insoluble solvophobic core surrounded by the solvophilic shell of side chains.

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