Grafted chains in polymer brushes

GAO AND OU-YANG Kinetics of Grafted Chains in Polymer Brushes... 

The stretching in a grafted chain (or polymer brush) is a fimction of the distance to the interface. While close to the interface the stretching may be very large (depending on the interfacial tension), it vanishes at the surface of the pol5mier brush, where the chain approaches a random coil conformation. A certain interpenetration of similar chains always occurs when brushes with chemically similar chains are in contact with each other, as it is in the case of microphase-separated block copolymers in the bulk state. Since the interpenetration in these cases occurs... 

As mentioned above, the grafting to technique enables in a one-pot reaction the synthesis of Au NPs stabilized by sulfur-containing polymers, which bear functional groups such as dithioester, trithioester, thiol, thioether and disulfide at the end of a polymer chain or in the middle. This method leads to nanoparticles similar to those obtained by the Brust-Schiffrin method in which alkanethiol-protected Au NPs of small size are obtained. This grafting to technique leads to very stable nanomaterials that also present a high surface graft density of polymer brush on the Au NP surface. 

Most of the discussion above has been for brushes in a good solvent. Williams [75] has applied the blob model for polymer brushes to grafted chains in a poor solvent. In this case, the blobs no longer repel but attract, leading to a reduction... 

When a linear polymer is grafted with a large number of much shorter side chains, cylindrical polymer brushes are formed [33, 108-111]. They are also denoted as bottlebrushes or molecular brushes. Although most cylindrical polymer brushes contain linear side chains, dendritic or even hyperbranched space demanding grafts can also render cylindrical shapes, which leads to the so-called dendronized [112-116] andhypergrafted[117, 118] polymers, respectively. In this review, we will focus on cylindrical brushes with linear side chains. Due to their anisotropic nature in topology, they have attracted more and more research interest in their synthesis, bulk, or solution properties, as well as applications. 

In cases when the two surfaces are non-equivalent (e.g., an attractive substrate on one side, an air on the other side), similar to the problem of a semi-infinite system in contact with a wall, wetting can also occur (the term dewetting appHes if the homogeneous film breaks up upon cooHng into droplets). We consider adsorption of chains only in the case where all monomers experience the same interaction energy with the surface. An important alternative case occurs for chains that are end-grafted at the walls polymer brushes which may also undergo collapse transition when the solvent quality deteriorates. Simulation of polymer brushes has been reviewed recently [9,29] and will not be considered here. 

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