Continuous Process for the Synthesis of Dendrimer-Like Star Polymers by Anionic Polymerization

Drug-dendrimer complexes and conjugates: Detailed furtherance through theory and experiments

Dendritic nanovectors-based drug delivery has gained significant attention in the past couple of decades. Dendrimers play a crucial role in deciding the solubility of sparingly soluble drug molecules and help in improving pharmacokinetics. A few important steps in drug delivery through dendrimers, such as drug encapsulation, formulation, and target-specific delivery, play an important role in deciding the fate of a drug molecule. It is also of prime importance to understand the interactions between a drug molecule and dendrimers at atomistic levels to decode the mechanism of action of drug-dendrimer complexes and their reliability in terms of drug delivery. Colossal progress in current experimental and computational approaches in the field has resulted in a vast amount of data that needs to be curated to be further implemented efficiently. Improved computational power has led to greater accuracy and prompt predictions of properties of drug-dendrimer complexes and their mechanism of action. The current review encapsulates the pioneering work in the field, experimental achievements in terms of drug delivery, and newer computational techniques employed in the advancement of the field.

Star amphiphilic block copolymers: synthesis via polymerization-induced self-assembly and crosslinking within nanoparticles, and solution and interfacial properties

The star amphiphilic block copolymer of star s-PNIPAM-b-PS is synthesized and it shows characteristics significantly different from those of the linear block copolymer counterpart.

Relationships between Architectures and Properties of Highly Branched Polymers: The Cases of Amorphous Poly(trimethylene carbonate) and Crystalline Poly(ε-caprolactone)

Highly branched polymers (HBPs) are a special class of functional polymeric materials and possess unique properties due to their unique topological structure. A new series of highly branched linear-comb and star-comb amorphous poly(trimethylene carbonate)s (PTMC) and crystalline poly(ε-caprolactone)s (PCL) with well-defined structure and high molecular weight were first synthesized using hydroxylated polybutadiene (HPB) as macroinitiators by simple "one-step" and "graft from" strategies. It is expected that the impact of long-chain, highly branched architecture on the properties of amorphous and crystalline polymers, respectively, is different. We explored systematically for the first time the effect and comparison of branched architectures on the physical and chemical properties of highly branched PTMCs and PCLs, including the intrinsic viscosity, glass transition, thermal degradation, creep property, rheological property, and crystallization and melting behaviors. It is found that the intrinsic viscosities in solution for both comb-branched PTMCs and PCLs were much lower compared with their linear and star counterparts arise from more compact structure and smaller hydrodynamic volumes. For amorphous PTMC, the creep strain and rate increased remarkably with degree of branching increasing due to the shorter side chains making it difficult for the highly branched molecules to entangle. For crystalline PCL, both WAXD and DSC analysis of PCLs with different topological structures indicated that the comb branched architectures have no significant influence on the crystal structure of PCL, but greatly promote the crystallization behavior, e.g., higher crystallinities. The deep understanding of structure-property relationship expects to guide the synthesis of designed functional polymer materials and the processing of polymer products.

Recent development of unimolecular micelles as functional materials and applications

Unimolecular micelles have high functionalities, encapsulation capabilities and site specific confinement abilities in various applications.

From vesicles to micelles: microphase separation of amphiphilic dendrimer copolymers in a selective solvent

The microphase separation of amphiphilic dendrimer copolymers in a selective solvent with different excluded volume effects (αS) is investigated using three-dimensional real space self-consistent field theory. The morphological transition of disorder-to-order and order-to-order is observed by systematically regulating the excluded volume effect parameter, interaction parameter of block species, and the spacer length of the second generation of the dendrimer. The ordered segregates of the dendrimer solution are observed with a stronger excluded volume effect due to the strong depletion effect of solvent on the dendrimer. The relative magnitude between hydrophobic block B and hydrophilic block C is very important for microphase separation: when they are equal (NB = NC), a structural shift from vesicles to micelles has been found upon increasing the interaction parameter, and the region of disordered morphology is controlled by the interfacial free energy (Uint); when NB > NC, the vesicular morphologies overwhelmingly appear in the ordered region and then NC increases to close to NB, and the ordered aggregates take a shift from vesicles to micelles. Furthermore, the amphiphilic block C of the dendrimer is intended to enlarge to NC > NB, the micellar morphology is dominant in the ordered regime with a stronger excluded volume effect, which contributes to the decrease in the hydrophobic block repulsion that is affected by the decrease in the entropic free energy (-TS). The knowledge obtained from the microphase separation of dendrimer solution induced by the excluded volume effect of selective solvent is full of referential significance in understanding the morphological transition from vesicles to micelles for the amphiphile in the field of soft matter.

Synthesis and unimolecular micelles of amphiphilic copolymer with dendritic poly(l-lactide) core and poly(ethylene oxide) shell for drug delivery

A novel type of amphiphilic copolymer POSS-(G₃-PLLA-b-PEO-COOH)₈ with a hydrophobic third-generation dendritic PLLA core and a functionalized hydrophilic PEO shell with surface carboxylic groups was synthesized as a carrier for drug delivery.

Efficient and economical synthesis of dendrimer-like polystyrene with long subchains through arm-first divergent strategy

Arm-first divergent approach combined with selective precipitation has been developed to synthesize dendrimer-like polystyrenes efficiently and economically.