Responsive Linear‐Dendritic Block Copolymers

Abstract

The combination of dendritic and linear polymeric structures in the same macromolecule opens up new possibilities for the design of block copolymers and for applications of functional polymers that have self‐assembly properties. There are three main strategies for the synthesis of linear‐dendritic block copolymers (LDBCs) and, in particular, the emergence of click chemistry has made the coupling of preformed blocks one of the most efficient ways of obtaining libraries of LDBCs. In these materials, the periphery of the dendron can be precisely functionalised to obtain functional LDBCs with self‐assembly properties of interest in different technological areas. The incorporation of stimuli‐responsive moieties gives rise to smart materials that are generally processed as self‐assemblies of amphiphilic LDBCs with a morphology that can be controlled by an external stimulus. Particular emphasis is placed on light‐responsive LDBCs. Furthermore, a brief review of the biomedical or materials science applications of LDBCs is presented.

Self-assembly of thermo and light responsive amphiphilic linear dendritic block copolymers

“…[6] In the last few years stimuli responsive linear-dendritic block copolymers (LDBCs) have been explored where the well-defined periphery of the dendritic block makes them perfect systems to perfectly control the incorporation of functionalization. [7] From the several possibilities, we have focused our attention on the probably most versatile synthetic strategy for LDBCs which is the coupling of the two constitutive blocks using the copper(I) catalyzed alkyne-azide cycloaddition (CuAAC), where each block is synthetized separately having either azide or alkyne functional groups. Linear polymer chains with terminal alkyne groups are easily approachable by atom transfer radical polymerization (ATRP) using an appropriate initiator.…”

Photoresponsive assemblies of linear-dendritic copolymers containing azobenzene in the dendron interior: the effect of the dendron structure on dye encapsulation and release

“…The trans isomer is converted to cis isomer upon exposure to UV light and the process is reversed upon illumination with visible light or thermally by storage in the dark. [19][20][21] Linear-dendritic copolymers [22][23][24] are an interesting class of polymer architecture that combines useful attributes of the perfectly branched dendron and linear polymer chain, for example dened number of functionalities can be installed at desired positions in the dendron. This can be exploited to cause complete disruption or changes in morphology of polymer assemblies leading to release of the guest molecules.…”

Controlled micellar disassembly of photo- and pH-cleavable linear-dendritic block copolymers

“…Linear-dendritic copolymers have many advantages over linear polymers due to the multivalent and perfectly branched structure of dendron, and chain entanglement of linear segment. [12][13][14][15][16][17][18][19] Among the stimuli-responsive groups, cleavable linkages are of particular interest due to the possibility of complete as well as controlled disassembly of the carrier. 10,11 To further enhance the effectiveness of micellar carriers assembled from amphiphilic polymers it is important to incorporate stimuli-responsive moieties into the polymer chain so that the cargo can be released at specific targets.…”