Fabrication of Surface Polymer Brushes Via Thin Film Crystallization and Solvent Annealing

Abstract

Polymer single crystals are used as templates to synthesize polymer brushes, known as the "polymer-single-crystal-assisted-grafting-to" (PSCAGT) approach. Polymer brushes with controlled grafting densities and spatial tethering locations are demonstrated. Previous works focused on solution crystallization, which involves large amounts of organic solvent, and the grafting density can only be tuned by varying crystallization temperatures. In this work, thin film crystallization is utilized to fabricate 2D polymer crystals on flat surfaces. Subsequent chemical tethering leads to polymer brushes that retain the original morphology of the crystals with high fidelity. Furthermore, it is shown that the grafting density of the polymer brushes fabricated using this method depends on the chain end distribution on the top/bottom surfaces of the crystal, which can be facilely controlled by annealing the crystals at various nonsolvent media. This work broadens the scope of the PSCAGT method and provides a new route to achieve polymer brushes with controlled structures.

Strength Enhancement of Polyurethane Film by Solution Annealing

“…The mismatch supramolecular interaction formed between rigid and flexible supramolecular fragments is used to realize the toughness of thermoplastic elastomers and thus improve their mechanical properties, but the synthesized elastomers become yellow due to the introduction of aromatic structure . So it can be concluded that the properties of polyurethane membranes can be improved by controlling several factors, such as intermolecular hydrogen bonds, molecular cross-linking structure, molecular weight, molecular structure symmetry, and so on. − …”