Micellization of Photo-Responsive Block Copolymers

Abstract

This review focuses on block copolymers featuring different photo-responsive building blocks and self-assembly of such materials in different selective solvents. We have subdivided the specific examples we selected: (1) according to the wavelength at which the irradiation has to be carried out to achieve photo-response; and (2) according to whether irradiation with light of a suitable wavelength leads to reversible or irreversible changes in material properties (e.g., solubility, charge, or polarity). Exemplarily, an irreversible change could be the photo-cleavage of a nitrobenzyl, pyrenyl or coumarinyl ester, whereas the photo-mediated transition between spiropyran and merocyanin form as well as the isomerization of azobenzenes would represent reversible response to light. The examples presented cover applications including drug delivery (controllable release rates), controlled aggregation/disaggregation, sensing, and the preparation of photochromic hybrid materials.

Polymeric Photoacids Based on Naphthols—Design Criteria, Photostability, and Light‐Mediated Release

“…[10] Often, these materials are classified according to whether the underlying photochemical process is reversible or irreversible,i na ddition to synthetic access to different materials. [8,11] Especially the latter experienced a boost with the advent of controlled/"living" radical polymerization techniques such as atom transfer radicalp olymerization (ATRP), [12] nitroxide-mediatedp olymerization (NMP), [13] andr eversible addition-fragmentation chain transfer (RAFT) polymerization [14] -together with post-polymerizationm odification of, for example, activatede ster moieties if direct access to ac ertain photoswitch is hampered. [15] Prominent examples of an irreversible photo-response include photo-cleavage of nitrobenzyl or pyrenyl esters and the formation of hydrophilic carboxylic acid groups along the polymer backbone, [16] whereas ar eversible photo-response is often realized using diarylethenes, azobenzenes, or spiropyran moieties.…”

Exploring Poly(ethylene glycol)-Polyzwitterion Diblock Copolymers as Biocompatible Smart Macrosurfactants Featuring UCST-Phase Behavior in Normal Saline Solution

“…Though pH-responsive polymers have been most commonly employed in practice until now, thermoresponsive systems have been increasingly explored as they allow for use in closed systems as well as under rather mild conditions. This seems to qualify them in particular for applications in fields such as cosmetics, personal care, biotechnology and biomedicine [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Obviously in such a context, the use of highly biocompatible polymers is preferable [ 22 , 28 ].…”

Shape-Memory Polymers in Dentistry: Systematic Review and Patent Landscape Report

“…Some of these materials, known as “smart” materials (SMs) or “(stimuli-)responsive” materials (SRMs), have a high capacity to sense and react according to environmental changes or external stimuli [3] (Figure 1): under a specific input, they produce a predictable and repeatable response or output. Such stimuli include: physically-dependent stimuli (e.g., temperature [4], electric fields [5], specific wavelength [6], ultrasound [7], magnetic fields [8], mechanical deformation [9]), chemically-dependent stimuli (e.g., pH [10], ionic strength [11], redox [12], solvent [13]), biologically-dependent stimuli (e.g., glucose [14], glutathione [15], enzymes [16], inflammatory metabolites [17]). A key feature of smart behaviour includes the ability to return to the original state after a stimulus has been removed [18].…”