Self-Assembly and Dual-Stimuli Sensitivities of Hydroxypropylcellulose-graft-poly(N,N-dimethyl aminoethyl methacrylate) Copolymers in Aqueous Solution

Abstract

The self-assembly and pH- and thermo-sensitivities properties of hydroxypropyl cellulose-graft-poly(N,N-dimethyl aminoethyl methacrylate) (HPC-g-PDMAEMA) copolymers in aqueous solutions were investigated by transmittance, dynamic light scattering (DLS), and (1)H NMR spectroscopy. Micelles with different structure can be formed by varying either pH value or temperature. At low pH, e.g., 3.0, the HPC backbone of the copolymer collapse to form the core of micelles stabilized with protonated PDMAEMA side chains on the surface of the micelles upon heating. At the medium pH, e.g., 8.1, both HPC backbone and PDMAEMA side chains collapse upon heating to form unstable aggregates. At high pH, e.g., 12.3, PDMAEMA side chains collapse first to form the core of micelles stabilized with HPC chains upon heating. Further heating the copolymer solution at this pH leads to the aggregation of the micelles due to the collapse of the shell HPC chains. The thermal sensitivity of the HPC-g-PDMAEMA copolymers is reversible.

Dual-stimuli responsive behaviors of diblock polyampholyte PDMAEMA-b-PAA in aqueous solution

“…Turbidity measurement is a common technique for estimating the LCST of the thermo-responsive polymers in aqueous solutions [6,9,33]. The PDMAEMA-b-PAA is a typical diblock polyampholyte with both thermal-and pH-responsive sensitivities because the PDMAEMA block is thermal-responsive and both AA and DMAEMA monomers are weak electrolytes.…”

“…Patrickios and co-workers [34] found that the cloud point of PDMAEMA stars in pure water does not rely much on the arm number. Ma et al [9] studied the thermo-responsive properties of hydroxypropyl cellulose-graft-poly(N,N-dimethyl aminoethyl methacrylate) (HPC-g-PDMAEMA) at different pHs and found that the LCST of HPC-g-PDMAEMA was dramatically varied on the solution pH. In this work, the aim is to research how the LCST varies with solution concentration and pH in the PDMA-EMA-b-PAA with different thermal-segment lengths.…”

“…Those polymers possess single/multiple stimuli sensitivities in a predictable manner and would be of great interest for various applications such as drug delivery [2][3][4][5][6] and catalysis [7,8]. In recent years, many works have been reported on the investigations of graft copolymer [9], homopolymer [10] and random copolymer [11]. However, the synthesis and characterization of dual-stimuli sensitivities diblock copolymer are still underdeveloped.…”

Cellulosic nanocomposite membranes from hydroxypropyl cellulose reinforced by cellulose nanocrystals

“…Moreover, HPC has a lower critical solution temperature (LCST, *41°C) in water. Heating a dilute HPC water solution to temperatures only a couple of degrees higher than the LCST can lead to metastable nanosphere aggregates instead of precipitation (Gao et al 2001), which means that HPC can demonstrate a corresponding phase change when controlling the water solution temperature (Ma et al 2010b). To the best of our knowledge, the effects of the use of temperature-responsive HPC as a matrix and the corresponding effect of its phase change on the mechanical properties of CNCs/HPC nanocomposites has never been studied.…”

Synthesis and assembly of polyhedral oligomeric silsesquioxane end-capped amphiphilic polymer to enhance the fluorescent intensity of tetraphenylethene

“…Ma et al reported a pH-responsive POSS end-capped polymer, POSS-PDMAEMA, and studied the self-assembly behaviour of POSS-PDMAEMA in aqueous solution [19]. PDMAEMA is a weak cationic polyelectrolyte that is water soluble and sensitive to pH [20][21][22][23][24][25]. Polymethyl methacrylate (PMMA) is hydrophobic and widely used to form copolymer with hydrophilic polymer.…”