Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

Introduction to Spectroscopy

https://pure.rug.nl/ws/files/127479671/1_s2.0_S0144861720305245_main.pdf

Modification of starch: A review on the application of “green” solvents and controlled functionalization

The broad diversity of structures and the presence of numerous functional groups available for chemical modifications represent an enormous advantage for the development of safe, non-toxic, and cost-effective micellar drug delivery systems (DDS) based on natural biopolymers, such as polysaccharides, proteins, and peptides. Different drug-loading methods are used for the preparation of these micellar systems, but it appeared that dialysis is generally recommended, as it avoids the formation of large micellar aggregates. Moreover, the preparation method has an important influence on micellar size, morphology, and drug loading efficiency. The small size allows the passive accumulation of these micellar systems via the permeability and retention effect. Natural biopolymer-based micellar DDS are high-value biomaterials characterized by good compatibility, biodegradability, long blood circulation time, non-toxicity, non-immunogenicity, and high drug loading, and they are biodegraded to non-toxic products that are easily assimilated by the human body. Even if some recent studies reported better antitumoral effects for the micellar DDS based on polysaccharides than for commercial formulations, their clinical use is not yet generalized. This review is focused on the studies from the last decade concerning the preparation as well as the colloidal and biological characterization of micellar DDS based on natural biopolymers.

Micellar Drug Delivery Systems Based on Natural Biopolymers.

Preparation and performance of a novel starch-based inorganic/organic composite coagulant for textile wastewater treatment

Transparent, flexible, and multifunctional starch-based double-network hydrogels as high-performance wearable electronics.

A series of highly branched random copolymers of acrylamide (AM) and N-isopropylacrylamide (NIPAM) have been prepared from a waxy potato starch-based macroinitiator by aqueous Cu0-mediated living radical polymerization (Cu0-mediated LRP) The NIPAM intake in the copolymer was varied between 0% and 50 mol % to evaluate the influence of chain composition on the aqueous rheological properties as well as their low critical solution temperature (LCST) The viscosity of the copolymer was found to increase with the NIPAM intake and an LCST can be observed when the NIPAM content is high enough (eg, 50 mol %) In addition, thermo-thickening behavior was observed at a low shear rate (γ ≤ 10 s−1) and higher NIPAM content was found to shift the onset of thermo-thickening behavior to a lower temperature However, the absolute increase in viscosity values is reduced with the NIPAM intake Besides this, an interesting significant thermo-thickening behavior was also observed on highly branched starch-g-polyacrylamide at high temperatures (>80 °C), which has not been previously reported Rheology tests also revealed a good salt-resistant property in copolymers with low NIPAM content (eg, <25 mol %) Considering the viscosity profile in saline as compared to that in pure water, this NIPAM intake seems to represent an optimum balance of viscosity and salt-resistance performance

/pdf/thermo-responsive-starch-g-pam-co-pnipam-controlled-3az3uqup8u.pdf

Thermo-Responsive Starch-g-(PAM-co-PNIPAM): Controlled Synthesis and Effect of Molecular Components on Solution Rheology

[2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) is a well-studied sulfobetaine-methacrylate as its zwitterionic structure allows the synthesis of polymers with attractive properties like antifouling and anti-polyelectrolyte behavior. In the present work, we report the Cu0-mediated living radical polymerization (Cu0-mediated LRP) of SBMA in sodium nitrate aqueous solution instead of previously reported solvents like trifluoroethanol and sodium chloride aqueous/alcoholic solution. Based on this, starch-g-polySBMA (St-g-PSBMA) was also synthesized homogeneously by using a water-soluble waxy potato starch-based macroinitiator and CuBr/hexamethylated tris(2-aminoethyl)amine (Me6TREN) as the catalyst. The structure of the macroinitiator was characterized by 1H-NMR, 13C-NMR, gHSQC, and FT-IR, while samples of PSBMA and St-g-PSBMA were characterized by 1H-NMR and FT-IR. Monomer conversion was monitored by 1H-NMR, on the basis of which the reaction kinetics were determined. Both kinetic study and GPC results indicate reasonable controlled polymerization. Furthermore, a preliminary study of the thermal response behavior was also carried through rheological tests performed on aqueous solutions of the prepared materials. Results show that branched zwitterionic polymers are more thermal-sensitive than linear ones.

/pdf/synthesis-of-zwitterionic-copolymers-via-copper-mediated-5584ggwh9e.pdf

Synthesis of Zwitterionic Copolymers via Copper-Mediated Aqueous Living Radical Grafting Polymerization on Starch

https://pure.rug.nl/ws/files/58453204/1_s2.0_S0144861718302972_main.pdf

Copper-mediated homogeneous living radical polymerization of acrylamide with waxy potato starch-based macroinitiator.

In this research, waxy potato starch, a high-molecular-weight natural polysaccharide with a highly branched structure, was used to homogeneously synthesize macroinitiator for controlled radical polymerization. With the starch-based macroinitiator, controlled grafting of acrylamide/N-isopropylacrylamide/sodium 2-acrylamido-2-methyl-1-propanesulfonate (AM/NIPAM/SAMPS) was studied via aqueous copper-mediated living radical polymerization (Cu0-mediated LRP) with tris[2-(dimethylamino)ethyl]amine (Me6Tren) as catalysis at room temperature. Compared with copper that generated from the disproportionation of CuBr in water, direct addition of copper powder to the system was proved to be more efficient for the synthesis of long-chain (co)polymers. The degree of polymerization was then set to 5000 and ratio of AM/NIPAM/SAMPS was varied to investigate the influence of chain composition on the rheological properties of copolymer water solution. Results suggest that 25 mol% is the optimum NIPAM intake for starch-g-poly(AM-co-NIPAM) to display both thermo-thickening property and stable viscosity in saline solution. This is preferable for potential applications like enhance oil recovery (EOR). However, this two-component copolymer dissolves slowly in water due to the strong intramolecular hydrogen bond between AM units. To overcome this problem, SAMPS was introduced to the copolymer. 25 mol% of SAMPS was proved to be the optimum intake for balanced performance in viscosity and saline-resistance. The intake of 25 mol% NIPAM, just contrary to what expected, although endow the starch-g-poly(AM-co-NIPAM-co-SAMPS) copolymer with thermo-thickening property at low shear rate (≤ 3 s-1) in saline solution, the viscosity is lower than starch-g-poly(AM-co-SAMPS) possibly due to the intramolecular association between NIPAM units.

/pdf/controlled-synthesis-of-starch-based-branched-polymers-4bqidw3w8p.pdf

Yifei Fan

Papers

Modification of starch: A review on the application of “green” solvents and controlled functionalization

Thermo-Responsive Starch-g-(PAM-co-PNIPAM): Controlled Synthesis and Effect of Molecular Components on Solution Rheology

Synthesis of Zwitterionic Copolymers via Copper-Mediated Aqueous Living Radical Grafting Polymerization on Starch

Copper-mediated homogeneous living radical polymerization of acrylamide with waxy potato starch-based macroinitiator.

Controlled synthesis of starch-based branched polymers