Tetraphenylethene-Functionalized Polyethylene-Based Polymers with Aggregation-Induced Emission

Abstract

A novel synthetic strategy toward a series of tetraphenylethene (TPE)functionalized polyethylene-based homo/copolymers is presented. Tris(3-(4-(1,2,2triphenylvinyl)phenoxy)propyl)borane, synthesized by hydroboration of (2-(4-(allyloxy)phenyl)ethene-1,1,2-triyl)tribenzene with BH3, was used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined TPE-terminated linear polyethylene (PE). Combining this efficient strategy with ring-opening polymerization (ROP) or atom transfer radical copolymerization (ATRP) TPE-functionalized PE-based block copolymers have been synthesized. All synthesized polymers showed aggregation-induced emission (AIE)-behavior either in solution or in bulk. Self-assembly of the PE-based block copolymer in DMF resulted in strong emission due to the AIE effect of the aggregated TPE-PM core, the fluorescence intensity of the solution is directly related to the composition of block copolymers and the size of the micelle. The response of the AIE-operative fluorescence behavior toward the concentration of the block copolymer solutions has also been used to locate the CMC value of the block copolymers. The non-emissive dilute solutions of block copolymers became fluorescent when increasing concentrations above CMC. ASSOCIATED CONTENT Supporting Information. Additional figures are presented in the supporting inforamtion. This material is available free of charge via the Internet at http://pubs.acs.org.

3,4-Ethylenedioxythiophene (EDOT) End-Group Functionalized Poly-ε-caprolactone (PCL): Self-Assembly in Organic Solvents and Its Coincidentally Observed Peculiar Behavior in Thin Film and Protonated Media

“…The possible explanations for all phenomena described above are as follows: (i) the blue-shifting of λ max em registered in the polar ACN solvent could be due to the stabilization of the ground state of EDOT-PCL, which has an increased polar character than the excited state; (ii) the bimodal shape and presence of the red-shifted peaks in both the investigated solvents, (the last one being a mark for the formation of the nanoparticles/micelle-like particles [ 55 , 72 , 77 ]), could be proof of the self-assembling nature of EDOT-PCL in the solution; (iii) the increased values of apparent hydrodynamic diameter (D h ) of the self-assembled structures in ACN in comparison with those formed in Chl, experimentally determined (vide infra) could be the reason for the observed fluorescence intensity decrease in this solvent. This behavior followed the well-established phenomenon of the dependence of fluorescence intensity on particle size [ 7 , 55 ]. In general, the results obtained from the fluorescence measurements lead to the conclusion that particular interactions with each of the solvents used in OCL chains (as a major component of EDOT-PCL ) as well as OCL-adopted conformation (extended in Chl or collapsed in ACN) are two of the most influential factors on this property.…”

“…As different properties have been demonstrated through a comparison with the classical, linear arrangement of the chain [ 2 ], the goal of producing polymers with complex architectures can be achieved by applying the concept “from functionality to function”. In this regard, polymeric materials with specific chain-end functionality have become accessible, especially through “living” controlled polymerizations [ 3 , 4 ], which have led to the production of valuable materials with new and improved properties [ 5 , 6 , 7 ] and to reactive intermediates of great interest for the construction of polymers with defined molecular architectures [ 4 , 8 , 9 ]. In bulk, in solution, or in film, placed at the chain-end of the homopolymers or copolymers, and even in blends of them, the end-groups impact their properties at both the molecular and supramolecular level.…”

“…One consequence of the confinement effect caused by the end-group is that the block copolymers morphology is radically modified, resulting in unparalleled property changes [ 8 ]. Additionally, the existing polymer properties, such as enzymatic degradation [ 6 ], of the solution–protein interaction [ 10 ] or the drug loading capacity [ 5 ] can be manipulated through the functional end-groups, or other new properties can be added such as fluorescence properties [ 7 , 11 ].…”

“…Thus, innovative uses of ε-caprolactone-based segments in sophisticated polymer architectures or micellar systems have also been noted [ 21 ]. Thus, the end-group functionalization of PCL means that it can be applied in, for example, more efficient drug delivery systems [ 5 , 11 ] and in aggregation-induced emission (AIE) materials [ 7 ], as catalytically active recyclable materials, or as magnetically responsive, luminescent materials [ 29 ]. Moreover, functional groups have often been added to PCL to transform it into a reactive intermediate in order to subsequently use them in coupling reactions.…”

In Situ Methylation Transforms Aggregation‐Caused Quenching into Aggregation‐Induced Emission: Functional Porous Silsesquioxane‐Based Composites with Enhanced Near‐Infrared Emission

“…[11] Aggregation-induced emission (AIE) is the complete opposite of ACQ, and has recently emerged as an unique synthetic target to functionally useful new molecules and materials. [12] As might be anticipated, AIE fluorophores generally exhibit reduced emission in dilute solutions and enhanced emission in aggregated or solid states. [13] This feature is attributed to inhibition of intramolecular rotation, intermolecular dipole contacts and π-π interactions.…”