Effect of the macromolecular architecture on the thermoresponsive behavior of poly(N-isopropylacrylamide) in copolymers with poly(N,N-dimethylacrylamide) in aqueous solutions: Block vs random copolymers

2021 ◽  
pp. 105150
Author(s):  
Yuan Zhang ◽  
Peng Wang ◽  
Ruwei Chen
Keyword(s):  
Aqueous Solutions ◽  
Random Copolymers ◽  
Macromolecular Architecture

Invertible vesicles and micelles formed by dually-responsive diblock random copolymers in aqueous solutions

Soft Matter ◽  
2014 ◽  
Vol 10 (32) ◽  
pp. 5886-5893 ◽  
Author(s):  
Mohammad T. Savoji ◽  
Satu Strandman ◽  
X. X. Zhu
Keyword(s):  
Aqueous Solutions ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Random Copolymers ◽  
Ethyl Methacrylate ◽  
Reversible Addition

Dually responsive diblock random copolymers poly(nPA0.8-co-DEAEMA0.2)-block-poly(nPA0.8-co-EA0.2) were made from random blocks of N-n-propylacrylamide (nPA), 2-(diethylamino)ethyl methacrylate (DEAEMA) and N-ethylacrylamide (EA) via reversible addition–fragmentation chain transfer (RAFT) polymerization.

scholarly journals Synthesis of P(MEO2MA-co-OEGMA) Random Copolymers and Thermally Induced Phase Transition Behaviors in Aqueous Solutions

2015 ◽  
Vol 31 (10) ◽  
pp. 1914-1923
Author(s):  
Yi. GUO ◽  
◽  
Heng-Jiang. LIU ◽  
Jie-Qiong. CHEN ◽  
Ya-Zhuo. SHANG ◽  
...  
Keyword(s):  
Phase Transition ◽  
Aqueous Solutions ◽  
Random Copolymers ◽  
Thermally Induced

Polypeptoids with tunable cloud point temperatures synthesized from N-substituted glycine N-thiocarboxyanhydrides

2015 ◽  
Vol 6 (16) ◽  
pp. 3164-3174 ◽  
Author(s):  
Xinfeng Tao ◽  
Jianwei Du ◽  
Youxiang Wang ◽  
Jun Ling
Keyword(s):  
Aqueous Solutions ◽  
Cloud Point ◽  
Random Copolymers

Poly(sarcosine-r-N-butylglycine) random copolymers with various MWs and compositions are synthesized from NTA monomers, which exhibit tunable Tcps in aqueous solutions.

scholarly journals Self-Association Behavior of Cell Membrane-Inspired Amphiphilic Random Copolymers in Water

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 327 ◽  
Author(s):  
Maho Ohshio ◽  
Kazuhiko Ishihara ◽  
Shin-ichi Yusa
Keyword(s):  
Aqueous Solutions ◽  
Fluorescence Probe ◽  
Nmr Relaxation ◽  
Radical Copolymerization ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Random Copolymers ◽  
Free Radical Copolymerization ◽  
Association Behavior ◽  
Self Association

Water-soluble and amphiphilic random copolymers (P(MPC/DMAx)) composed of hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) and hydrophobic n-dodecyl methacrylate (DMA) were prepared via reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. The compositions of DMA unit (x) in the copolymer were in the range of 0 to 38 unit mol %. The degree of polymerization of P(MPC/DMAx) was adjusted to about 200. Since the monomer reactivity ratios of MPC and DMA are 1.01 and 1.00, respectively, ideal free radical copolymerization occurred. In aqueous solutions, interpolymer aggregation occurred due to the hydrophobic pendant n-dodecyl groups. The aggregation number (Nagg) increased with an increasing x. The mobilities of the DMA and MPC pendant groups in aqueous solutions were restricted, as confirmed by 1H NMR relaxation time measurements, because a part of the MPC units were trapped in the hydrophobic microdomain formed from the pendant n-dodecyl groups. The polarity of the hydrophobic microdomain formed from P(MPC/DMA38) in water was similar to that of ethyl acetate according to fluorescence probe experiments. No specific interactions were found in water between P(MPC/DMAx) and bovine serum albumin because the surface of the interpolymer aggregates contained only hydrophilic MPC units.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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