Spontaneous Formation of Giant Polymer Vesicles through a Nucleation and Growth Pathway

Interpolymer Complexes Based on Cellulose Ethers: Application

Interpolymer complexes based on cellulose ethers have gained significant interest in recent years due to their versatile applications. These complexes are formed by combining different polymers through non-covalent interactions, resulting in stable structures. This article provides an overview of the various fields where IPCs based on cellulose ethers find application. IPCs based on cellulose ethers show great potential in drug delivery systems. These complexes can encapsulate drugs and enable controlled release, making them suitable for sustained drug delivery. They offer advantages in terms of precise dosage and enhanced therapeutic efficacy. Coatings and adhesives also benefit from IPCs based on cellulose ethers. These complexes can form films with excellent mechanical strength and enhanced water resistance, providing durability and protection. They have applications in various industries where coatings and adhesives play a crucial role. In food packaging, IPCs based on cellulose ethers are highly relevant. These complexes can form films with effective barrier properties against oxygen and water vapor, making them ideal for packaging perishable foods. They help extend to shelf life of food products by minimizing moisture and oxygen transfer. Various methods, such as solvent casting, coacervation, and electrostatic complexation, are employed to synthesize IPCs based on cellulose ethers.

Nanoscale vesicles assembled from non-planar cyclic molecules for efficient cell penetration

A new approach to the development of functional biomaterials is to obtain a controllable nanostructure through supramolecular self-assembly.

Self-Collapsing of Single Molecular Poly-Propylene Oxide (PPO) in a 3D DNA Network

On the basis of DNA self-assembly, a thermal responsive polymer polypropylene oxide (PPO) is evenly inserted into a rigid 3D DNA network for the study of single molecular self-collapsing process. At low temperature, PPO is hydrophilic and dispersed uniformly in the network; when elevating temperature, PPO becomes hydrophobic but can only collapse on itself because of the fixation and separation of DNA rigid network. The process has been characterized by rheological test and Small Angle X-Ray Scattering test. It is also demonstrated that this self-collapsing process is reversible and it is believed that this strategy could provide a new tool to study the nucleation-growing process of block copolymers.

Light-induced evolution of microaggregates: transformation to vesicles, cyclic growth and collapse and vesicle fusion

The self-assembled dynamic microaggregates were obtained in one pot via PISA and underwent visible light-induced evolutionary behaviors in the presence of nile red or rhodamine.

Structural and mechanical characteristics of polymersomes

Polymersomes self-assembled from amphiphilic macromolecules have attracted growing attention because of their multifunctionality and stability. By controlling the structural characteristics of polymersomes, including vesicle shape, size, and membrane thickness, their mechanical and transport properties as well as their fusion behavior can be manipulated. Numerous experimental techniques have been developed to explore polymersome characteristics; however, experimental microscopic observations and knowledge of vesicles are limited. Mesoscale simulations can complement experimental studies of the vesicular features at the microscopic level and thus provide a feasible method to better understand the relationship between the fundamental structures and physicochemical properties of polymersomes. Moreover, the predictive ability of the simulation approaches may greatly assist developments and future applications of polymersomes.

Bridging the gap in the micellar transformation from cylinders to vesicles

The micelles of polystyrene-block-poly(acrylic acid) (PS154-b-PAA49) are made to transform slowly in mixed solvent, allowing continual trapping of the various intermediates. During the transformation from cylindrical to vesicular micelles, it appears that a section of the cylinder first flattens to give a lamellar section, which then depresses to give a bowl-like moiety, before finally converting to a fully enclosed vesicle. Most part of this transformation involves the "flow" of polymer domains without mingling of the hydrophobic and hydrophilic domains. On the bases of the literature and the observation in this work, it is proposed that the reduction of surface-to-volume ratio provides the thermodynamic driving force for the cylinder-to-vesicle transformation, whereas molecular reorganization within the polymer domains creates the kinetic barrier. From the point of view of molecular interactions, the "flow" of polymer domain involves a low barrier, whereas the merging of two micelles, the severing of cylindrical micelles, and the closing of partial vesicles encounter high barriers. Moreover, the kinetic barrier is reduced when PSPAA containing shorter PAA blocks is used, or when the PAA block are protonated. This mechanistic proposal explains the kinetically controlled transformation pathway and structural features of the observed intermediates.

Formation and structural characteristics of thermosensitive multiblock copolymer vesicles

The spontaneous vesicle formation of ABABA-type amphiphilic multiblock copolymers bearing thermosensitive hydrophilic A-block in a selective solvent is studied using dissipative particle dynamics (DPD) approach. The formation process of vesicle through nucleation and growth pathway is observed by varying the temperature. The simulation results show that spherical micelle takes shape at high temperature. As temperature decreases, vesicles with small aqueous cavity appear and the cavity expands as well as the membrane thickness decreases with the temperature further decreasing. This finding is in agreement with the experimental observation. Furthermore, by continuously varying the temperature and the length of the hydrophobic block, a phase diagram is constructed, which can indicate the thermodynamically stable region for vesicles. The morphological phase diagram shows that vesicles can form in a larger parameter scope. The relationship between the hydrophilic and hydrophobic block length versus the aqueous cavity size and vesicle size are revealed. Simulation results demonstrate that the copolymers with shorter hydrophobic blocks length or the higher hydrophilicity are more likely to form vesicles with larger aqueous cavity size and vesicle size as well as thinner wall thickness. However, the increase in A-block length results to form vesicles with smaller aqueous cavity size and larger vesicle size.