Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Influence of the Polymer Microstructure over the Phase Separation of Thermo-Responsive Nanoparticles.

ABSTRACT: Thermo-responsive nanoparticles (NPs), i.e., colloids with a sharp and often reversible phase separation in response to thermal stimuli, are coming to the forefront due to their dynamic behavior, useful in applications ranging from biomedicine to advanced separations and smart optics. What is guiding the macroscopic behavior of these systems above their critical temperature is mainly the microstructure of the polymer chains of which these NPs are comprised. Therefore, a comprehensive understanding of the influence of the polymer properties over the thermal response is highly required to reproducibly target a specific behavior. In this study, we synthesized thermo-responsive NPs with different size, polymeric microstructure and hydrophilic-lipophilic balance (HLB) and investigated the role of these properties over their phase separation. We first synthesized four different thermo-responsive oligomers via Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization of poly(ethylene glycol)methyl ether methacrylate. Then, exploiting the RAFT living character, we chain-extended these oligomers with butyl methacrylate obtaining a library of NPs. Finally, we investigated the NP thermo-responsive behavior, their physical state above the cloud point (Tcp) as well as their reversibility once the stimulus is removed. We concluded that the solid content plays a minor role compared to the relative length of the two blocks forming the polymer chains. In particular, the longer the stabilizer, the more favored the formation of a gel. At the same time, the reversibility is mainly achieved at high HLB, independently from the absolute lengths of the block copolymers.

SUBMITTER: Manfredini N

PROVIDER: S-EPMC8037153 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Thermo- and Light-Responsive Polymer-Coated Magnetic Nanoparticles as Potential Drug Carriers.

Project description:A series of thermo- and light-responsive copolymers of poly (N-isopropylacrylamide) (PNIPAM) and 6-[4-(4-methoxy phenyl azo)-phenoxyl-hexyl methacrylate) (AzoMA) (PNIPAM-b-PAzoMA) were synthesized via reversible addition-fragmentation chain transfer (RAFT) radical polymerization. The resulting copolymers had a narrow molecular weight distribution range of 1.06-1.24, in which M n changed regularly with the monomer concentration. Subsequently, the diblock copolymers were successfully modified on the surface of iron oxide nanoparticles through the interaction between the chemical bonds to prepare Fe3O4@(PNIPAM-b-PAzoMA) nanoparticles. The size of fabricated nanoparticles with excellent thermo-sensitivity and photo-sensitivity was controlled at about 40-50 nm. Cell viability assays suggested that the nanoparticles showed no significant cytotoxicity and potential drug delivery in the tumor microenvironment.

| S-EPMC9315361 | biostudies-literature

A Thermo-Responsive Polymer Micelle with a Liquid Crystalline Core.

Project description:An amphiphilic diblock copolymer (PChM-PNIPAM), composed of poly(cholesteryl 6-methacryloyloxy hexanoate) (PChM) and poly(N-isopropyl acrylamide) (PNIPAM) blocks, was prepared via reversible addition-fragmentation chain transfer radical polymerization. The PChM and PNIPAM blocks exhibited liquid crystalline behavior and a lower critical solution temperature (LCST), respectively. PChM-PNIPAM formed water-soluble polymer micelles in water below the LCST because of hydrophobic interactions of the PChM blocks. The PChM and PNIPAM blocks formed the core and hydrophilic shell of the micelles, respectively. With increasing temperature, the molecular motion of the pendant cholesteryl groups increased, and a liquid crystalline phase transition occurred from an amorphous state in the core. With further increases in temperature, the PNIPAM block in the shell exhibited the LCST and dehydrated. Hydrophobic interactions of the PNIPAM shells resulted in inter-micellar aggregation above the LCST.

| S-EPMC9920352 | biostudies-literature

Hydroxypropyl cellulose as a green polymer for thermo-responsive aqueous foams.

Project description:Hydroxypropyl cellulose (HPC) is a surface active polymer that can change its solubility as a function of temperature. This makes HPC interesting for responsive foams, where macroscopic properties need to be reversibly changed on demand. Analysis of aqueous HPC foams as a function of temperature showed a moderate decrease in foam half-life time from 9000 to 4000 s, when the temperature was increased. However, within a narrow temperature range of ±2 °C a dramatic decrease in half-life time to <120 s was observed at 43 °C in the absence and at 31 °C in the presence of 0.7 M NaCl. These drastic changes are highly reversible and are associated to the lower critical solution temperatures (LCST) of HPC in aqueous solutions. In fact, dynamic light scattering experiments indicate that HPC molecules form aggregates at temperatures >31 °C (0.7 M NaCl) and >43 °C (0 M NaCl), which shrink in size when the temperature is increased further. From these results, we conclude that the LCST of 1 MDa HPC is at 43 °C when no salt is present and is at 31 °C in aqueous solutions with 0.7 M NaCl. In addition, shear rheology of bulk solutions and surface tensiometry indicate that the solution's viscosity and the surface pressure dramatically change at the respective LCSTs. Obviously, the solvent's viscosity triggers substantial changes in foam drainage at the LCST, which is shown to be the main driving force for the temperature responsiveness of HPC foams.

| S-EPMC6438354 | biostudies-literature

Role of the Polymer Microstructure in Controlling Colloidal and Thermo-Responsive Properties of Nano-Objects Prepared Via RAFT Polymerization in a Non-polar Medium.

Project description:After having demonstrated their potential in biomedical applications, thermo-responsive block copolymers that are able to self-assemble into nano-objects in response to temperature modifications are becoming more and more appealing in other sectors, such as the oil and gas and lubricant fields. Reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly has been demonstrated as a valuable strategy for producing nano-objects from modular block copolymers in non-polar media, required for the mentioned applications. Although the influence of the nature and size of the thermo-responsive block of these copolymers on the properties of the nano-objects is extensively studied in the literature, the role of the solvophilic block is often neglected. In this work, we elucidate the role of the main microstructural parameters, including those of the solvophilic portion, of block copolymers produced by RAFT polymerization in the hydrocarbon blend decane/toluene 50:50 v/v on the thermo-responsive behavior and colloidal properties of the resulting nano-objects. Two long-aliphatic chain monomers were employed for the synthesis of four macromolecular chain transfer agents (macroCTAs), with increasing solvophilicity according to the number of units (n) or length of the alkyl side chain (q). Subsequently, the macroCTAs were chain-extended with different repeating units of di(ethylene glycol) methyl ether methacrylate (p), leading to copolymers that are able to self-assemble below a critical temperature. We show that this cloud point can be tuned by acting on n, p, and q. On the other hand, the colloidal stability, expressed in terms of area of the particle covered by each solvophilic segment, is only a function of n and q, which provides a way for controlling the size distribution of the nano-objects and to decouple it from the cloud point.

| S-EPMC10373479 | biostudies-literature

Rapid Actuation of Thermo-Responsive Polymer Networks: Investigation of the Transition Kinetics.

Project description:The swelling and collapsing of thermo-responsive poly(N-isopropylacrylamide)-based polymer (pNIPAAm) networks are investigated in order to reveal the dependency on their kinetics and maximum possible actuation speed. The pNIPAAm-based network was attached as thin hydrogel film to lithographically prepared gold nanoparticle arrays to exploit their localized surface plasmon resonance (LSPR) for rapid local heating. The same substrate also served for LSPR-based monitoring of the reversible collapsing and swelling of the pNIPAAm network through its pronounced refractive index changes. The obtained data reveal signatures of multiple phases during the volume transition, which are driven by the diffusion of water molecules into and out of the network structure and by polymer chain re-arrangement. For the micrometer-thick hydrogel film in the swollen state, the layer can respond as fast as several milliseconds depending on the strength of the heating optical pulse and on the tuning of the ambient temperature with respect to the lower critical solution temperature of the polymer. Distinct differences in the time constants of swelling and collapse are observed and attributed to the dependence of the cooperative diffusion coefficient of polymer chains on polymer volume fraction. The reported results may provide guidelines for novel miniature actuator designs and micromachines that take advantages of the non-reciprocal temperature-induced volume transitions in thermo-responsive hydrogel materials.

| S-EPMC9059119 | biostudies-literature

Thermo-Responsive Cellulose-Based Material with Switchable Wettability for Controllable Oil/Water Separation.

Project description:A thermo-responsive cellulose-based material (cellulose-g-PNIPAAm) was prepared by grafting N-isopropylacrylamide (NIPAAm) onto bagasse pulp cellulose via Ce (IV)-initiated free radical polymerization. The surfaces of the obtained cellulose-g-PNIPAAm paper showed a rapid wettability conversion from being hydrophilic (water contact angles (WCA) of 0°) at 25 °C to becoming hydrophobic (WCA of 134.2°) at 45 °C. Furthermore, the thermo-responsive mechanism of cellulose-g-PNIPAAm was examined by the in situ variable-temperature 13C NMR, ¹H NMR and AFM analysis. At the same time, the resulting cellulose paper was applied for a switchable separation of oil/water mixtures. Water can pass through the paper under 45 °C, while oil is kept on the paper. When the temperature is above 45 °C, oil can permeate through the paper, while water cannot pass through the water. Moreover, the paper exhibited excellent regeneration performance after five cycles and maintained its switchable wettability.

| S-EPMC6403979 | biostudies-literature

Thermo-responsive aqueous two-phase system for two-level compartmentalization.

Project description:Hierarchical compartmentalization responding to changes in intracellular and extracellular environments is ubiquitous in living eukaryotic cells but remains a formidable task in synthetic systems. Here we report a two-level compartmentalization approach based on a thermo-responsive aqueous two-phase system (TR-ATPS) comprising poly(N-isopropylacrylamide) (PNIPAM) and dextran (DEX). Liquid membraneless compartments enriched in PNIPAM are phase-separated from the continuous DEX solution via liquid-liquid phase separation at 25 °C and shrink dramatically with small second-level compartments generated at the interface, resembling the structure of colloidosome, by increasing the temperature to 35 °C. The TR-ATPS can store biomolecules, program the spatial distribution of enzymes, and accelerate the overall biochemical reaction efficiency by nearly 7-fold. The TR-ATPS inspires on-demand, stimulus-triggered spatiotemporal enrichment of biomolecules via two-level compartmentalization, creating opportunities in synthetic biology and biochemical engineering.

| S-EPMC11310206 | biostudies-literature

Properties enhancement of carboxymethyl cellulose with thermo-responsive polymer as solid polymer electrolyte for zinc ion battery.

Project description:A novel polymer host from carboxymethyl cellulose (CMC)/poly(N-isopropylacrylamide) (PNiPAM) was developed for a high safety solid polymer electrolyte (SPE) in a zinc ion battery. Effects of the PNiPAM loading level in the range of 0-40% by weight ( wt%) on the chemical, mechanical, thermal, and morphological properties of the CMC/PNiPAMx films (where x is the wt% of PNiPAM) were symmetrically investigated. The obtained CMC/PNiPAMx films showed a high compatibility between the polymers. The CMC/PNiPAM20 blend showed the greatest tensile strength and modulus at 37.9 MPa and 2.1 GPa, respectively. Moreover, the thermal degradation of CMC was retarded by the addition of PNiPAM. Scanning electron microscopy images of CMC/PNiPAM20 revealed a porous structure that likely supported Zn2+ movement in the SPEs containing zinc triflate, resulting in the high Zn2+ ion transference number (0.56) and ionic conductivity (1.68 × 10-4 S cm-1). Interestingly, the presence of PNiPAM in the CMC/PNiPAMx blends showed a greater stability during charge-discharge cyclic tests, indicating the ability of PNiPAM to suppress dendrite formation from causing a short circuit. The developed CMC/PNiPAM20 based SPE is a promising material for high ionic conductivity and stability in a Zn ion battery.

| S-EPMC7387535 | biostudies-literature

Internal Microstructure Dictates Interactions of Polymer-grafted Nanoparticles in Solution.

Project description:Understanding the effects of polymer brush architecture on particle interactions in solution is requisite to enable the development of functional materials based on self-assembled polymer-grafted nanoparticles (GNPs). Static and dynamic light scattering of polystyrene-grafted silica particle solutions in toluene reveals that the pair interaction potential, inferred from the second virial coefficient, A 2, is strongly affected by the grafting density, σ, and degree of polymerization, N, of tethered chains. In the limit of intermediate σ (∼0.3 to 0.6 nm-2) and high N, A 2 is positive and increases with N. This confirms the good solvent conditions and can be qualitatively rationalized on the basis of a pair interaction potential derived for grafted (brush) particles. In contrast, for high σ > 0.6 nm-2 and low N, A 2 displays an unexpected reversal to negative values, thus indicating poor solvent conditions. These findings are rationalized by means of a simple analysis based on a coarse-grained brush potential, which balances the attractive core-core interactions and the excluded volume interactions imparted by the polymer grafts. The results suggest that the steric crowding of polymer ligands in dense GNP systems may fundamentally alter the interactions between brush particles in solution and highlight the crucial role of architecture (internal microstructure) on the behavior of hybrid materials. The effect of grafting density also illustrates the opportunity to tailor the physical properties of hybrid materials by altering geometry (or architecture) rather than a variation of the chemical composition.

| S-EPMC8361431 | biostudies-literature

Cell-compatible isotonic freezing media enabled by thermo-responsive osmolyte-adsorption/exclusion polymer matrices.

Project description:During the long-term storage of cells, it is necessary to inhibit ice crystal formation by adding cryoprotectants. Non-cell-permeable cryoprotectants have high osmotic pressure which dehydrates cells, indirectly suppressing intracellular ice crystal formation. However, the high osmotic pressure and dehydration often damage cells. Emerging polymer-type non-cell-permeable cryoprotectants form matrices surrounding cells. These matrices inhibit the influx of extracellular ice nuclei that trigger intracellular ice crystal formation. However, these polymer-type cryoprotectants also require high osmotic pressure to exert an effective cryoprotecting effect. In this study, we designed a poly(zwitterion) (polyZI) that forms firm matrices around cells based on their high affinity to cell membranes. The polyZI successfully cryopreserved freeze-vulnerable cells under isotonic conditions. These matrices also controlled osmotic pressure by adsorbing and desorbing NaCl depending on the temperature, which is a suitable feature for isotonic cryopreservation. Although cell proliferation was delayed by the cellular matrices, washing with a sucrose solution improved proliferation.

| S-EPMC10687075 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data