This review highlights the developments in dendrimer-based micelles for drug delivery. Dendrimers, the perfectly branched monodisperse macromolecules, have certain structural advantages that make them attractive candidates as drug carriers for controlled release or targeted delivery. As polymeric micelle-based approaches precede the work in dendrimers, these are also discussed briefly. The review concludes with a perspective on possible applications of biaryl-based dendrimeric micelles that exhibit environment-dependent conformations, in drug delivery.

A dibenzyl substituted poly (3,4-propylenedioxythiophene) was designed and synthesized, and exhibited a contrast of 89% at 632 nm with switching speeds of 400 ms and coloration efficiency of 575 cm 2 C 21 .Conjugated polymers 1 belong to an important class of polymers due to their widespread use in industrial applications like sensors, electrochromic materials, light emitting diodes (LEDs), actuators, and batteries etc. Electrochromics (ECs) are materials where the color exhibited is a function of applied potential. 2-4 Both inorganic and organic materials have been used as EC materials but there is still a lot of scope for further improvement in terms of switching speeds, stability, contrast and ease of synthesis and processing. Conducting or conjugated polymers have been found to be more promising as EC materials because of their better stability, faster switching speeds and easy processing compared to the inorganic EC materials. 2 EC materials where the color changes from a highly opaque colored state to highly transmissive bleached state are highly desirable as they are potential candidates for applications in display devices. In these systems, the change in percentage transmittance (D%T) between the two states is called the contrast and the higher the contrast, the better the material is for display applications. Conjugated polymers based on 3,4-alkylenedioxythiophene have attracted a lot of attention, both in academic as well as in industrial labs, as potential candidates for display applications because of their high contrast, low oxidation potential, better stability to air exposure at ambient and at elevated temperature conditions, and faster switching speeds. 5 Recently, Reynolds and coworkers have extensively studied the effect of ring size and also of ring substitution on the electrochromic properties of polymers based on 3,4-alkylenedioxythiophene. 5 They observed that the electrochromic contrast improves on increasing the ring size and also on increasing the interchain separation by the incorporation of a rigid/bulky side chain. 6 A tetradecyl substituted polyethylenedioxythiophene derivative was found to exhibit a D%T of 64%. However, the highest contrast (D%T of 78%) reported to date was observed in the case of a dimethyl substituted polypropylenedioxythiophene (PProDOT-Me 2 ). 7 Therefore, if one has to design a polymer with even better contrast than PProDOT-Me 2 one has to use more rigid/bulky substituents instead of methyl groups. Based on these facts, we designed and synthesized a dibenzyl propylenedioxythiophene (ProDOT-Bz 2 ) monomer (1). Incorporation of benzyl groups as the substituents, we think, will increase the interchain separation due to its rigid and bulky nature and hence the contrast. PProDot-Bz 2 exhibits an extremely high contrast of 89% at l max (632 nm) with coloration efficiencies of the order of 575 cm 2 C 21 ; in fact, these are the best reported values to date. In this communication, we report its synthesis, electrochemical and optical properties.The monomer 1 was synthe...

Block copolymers are key building blocks for a variety of applications ranging from electronic devices to drug delivery. The material properties of block copolymers can be tuned and potentially improved by introducing noncovalent interactions in place of covalent linkages between polymeric blocks resulting in the formation of supramolecular block copolymers. Such materials combine the microphase separation behavior inherent to block copolymers with the responsiveness of supramolecular materials thereby affording dynamic and reversible materials. This tutorial review covers recent advances in main-chain supramolecular block copolymers and describes the design principles, synthetic approaches, advantages, and potential applications.

A heterotelechelic poly(norbornene imide) containing two terminal and orthogonal hydrogen-bonding receptors, N,N'-bis[6-(alkanoylamino)pyridin-2-yl] isophthalamide (often referred to as the Hamilton receptor or Wedge) and 2,7-diamido-1,8-naphthyridine (DAN), at the opposite ends of the polymer was synthesized via ring-opening metathesis polymerization (ROMP) through the employment of a Hamilton receptor-functionalized ruthenium initiator and a DAN-based chain-terminator. In parallel, two monotelechelic polymers containing either cyanuric acid (CA)- or ureidoguanosine (UG)-end groups that are complementary to the hydrogen-bonding receptors along the poly(norbornene imide) were synthesized either also via ROMP by terminating the polymerization of norbornene octyl ester with a CA-based chain-terminator or by the reaction of poly(ethylene oxide) with UG. Complete incorporations of the hydrogen-bonding receptors at the chain-ends of all polymers were confirmed by (1)H NMR spectroscopy. The telechelic polymers can be self-assembled into ABC triblock copolymers following either a stepwise or a one-pot, orthogonal self-assembly protocol. The self-assembly process was monitored by (1)H NMR spectroscopy, revealing full orthogonality of the two recognition pairs, Hamilton receptor-CA and DAN-UG. The resulting supramolecular ABC triblock copolymers were further characterized by a series of methods including 2-D NOESY, isothermal titration calorimetry, and viscometry, proving that the two orthogonal hydrogen-bonding interactions are strong enough to hold the three polymer chains together. We suggest that a self-assembly methodology solely based on the fully orthogonal hydrogen-bonding recognition motifs will allow for an easy and rapid synthesis of architecturally controlled supramolecular polymeric assemblies with a high degree of complexity.