Literatura académica sobre el tema "Zwitterionization"

Surface zwitterionization of graphene oxide (GO) was firstly conducted by grafting poly(sulfobetaine methacrylate) (PSBMA) onto the GO surface via reverse atom transfer radical polymerization (RATRP).

Zwitterionization of multiwalled carbon nanotubes is conducted via atom transfer radical polymerization and ZCNTs obtained are used as an aqueous additive to fabricate thin-film nanocomposite nanofiltration membranes.

We report the synthesis of a new bistriarylamine series having a urea bridge and investigate its mixed-valence (MV) states by electrochemical and spectroelectrochemical methods. We found that the supporting electrolytes had unusual effects on potential splitting during electrochemical behavior, in which a smaller counteranion thermodynamically stabilized a MV cation more substantially than did a bulky one. The effects contrary to those reported in conventional MV systems were explained by zwitterionization through hydrogen bonding between the urea bridge and the counteranions, increasing the electronic interactions between two triarylamino units. Furthermore, we clarified the intervalence charge transfer characteristics of the zwitterionic MV state.

碩士
中原大學
化學工程研究所
103
Metal materials are widely used in medical device or parts, and the most common were medical grade titanium and stainless steel. Although metals have good mechanical properties and processing properties but lack biocompatibility when applied to human body, such as the reinforcement or repair, usually occurring of the foreign body granuloma, caused injured again. This study focuses on the self-assembling zwitterionization via thermal-induced immobilization method for metal substrates to achieve the general biofouling control. We use the zwitterionic sulfobetaine monomer (SBMA) and glycidyl methacrylate monomer (GMA) to synthesize a set of triblock copolymers (pSBMAn-b-pGMAn-b-pSBMAn; n = 25, 50, 75, 100) with controlled block ratios of SBMA/GMA. The study also discussed the effect of copolymer grafting density on its antifouling capability. The outstanding antifouling performance of zwitterionic pSBMA brushes within stable chemisorption via covalent bounding can be achieved by epoxy groups of polyGMA reacted with hydroxyl groups on surface, which was determined by 1H NMR. The results showed that stainless steel surfaces anchored with pSBMA brushes provide good fouling resistance in plasma proteins, blood cells, tissue cells and general bacterial. The results also showed the modification method successfully applied to the antifouing coating on surgical stainless steel blade and titanium metal root for the control of bacterial resistance.

碩士
中原大學
化學工程研究所
103
This work lays the focus on the use of a novel random zwitterionic copolymer, namely zP4VP-r-PODA, obtained by polymerization reaction between 4-vinylpyrrolidone and octadecyl acrylate, and by the subsequent action of iodoacetic acid, in order to modify polypropylene (PP) membranes and provide them with antifouling and hemocompatible properties. Once the result of polymer characterization presented, we move onto the physico-chemical characterization of the polypropylene (PP) membranes modified with zP4VP-r-PODA by self-assembling thermal evaporation process. Membranes are shown to efficiently resist to the adhesion of various proteins (bovine-serum-albumin, lysozyme) bacteria (Escherichia coli) blood cells (erythrocytes, leukocytes, thrombocytes) and whole blood cell. Along this manuscript, performances of membranes self-assembled with random copolymer before zwitterionization (P4VP-r-PODA) are systematically compared to those obtained with membranes modified with zP4VP-r-PODA. Overall, this study unveils that these novel modified PP membranes holds promise as an alternate material for blood filtration.

碩士
中原大學
化學工程研究所
104
Biomaterials are commonly used in medical proposes which needs to be directly in contact with human tissue, cells, and blood. Human blood is a very complex substance, when biomaterials are in contact with blood some phenomena will take effect like blood clotting. When biomaterials experience protein adsorption, platelet adsorption comes next and other bio foulants will also attach to the material. Excessive blood clotting can lead to oxygen deprivations in the tissue cells and may lead to fatal effects to human health. An ideal bioinert material needs to be designed in order to solve this problem. A bioinert material needs to exhibit nonspecific protein adsorption resistance, cell attachment, and bacteria attachment. This research performs surface modification via zwitterionzation of hydrophobic materials and perform a bio-inert control. In this research chose a zwitterionic material sulfobetaine methacrylate (SBMA), together with styrene which have strong hydrophobic property. In our previous work we try to synthesis a copolymer with these materials for different application, but because of the polarity of the components of the copolymer are very different, it is very hard to find an appropriate solvent to dissolve the copolymer. In this study we use reaction-induced molecular self-assembling for bio-inert control. Utilizing the property of styrene that have a strong hydrophobic force between hydrophobic surfaces hence can bind in the surface. In this study modified two materials and test by blood compatibility and general biocompatibility. The first part focuses on silicon wafer functionalized with CH3 on the surface. Using reaction-induced molecular self-assembling for bio-inert control we modified the CH3 functionalized wafers. Atomic force microscope (AFM) and scanning electron microscope (SEM) were used to evaluate the surface of the modified substrates. For hemocompatibility, different blood cells like platelets, leukocyte, erythrocytes, and whole blood were put in contact with the modified substrates to check for their attachment. Other general biocompatibility test were also performed like protein adsorption using single protein solution and platelet poor plasma, bacterial attachment, tissue cell attachment, clotting time, and hemolysis. The second part modifies polyvinylidene fluoride (PVDF) which is widely used in water filtration. It have desirable properties like good mechanical strength, and resistance to solvents, acids, bases and heat, but has a strong hydrophobic property hence will be easy to get fouling. If used in industrial water filtration, they use chemicals to clean the fouled membranes which have high costs and not desirable. The tests for surface morphology, general biocompatibility, and hemocompatibility tests were also done with PVDF. Additionally thermogravimetric analysis (TGA) was performed to evaluate the coating density on the membranes. We also tried to modify different hydrophobic surfaces like polydimethylsiloxane (PDMS), propylene (PP), polytetrafluoroethene (PTFE) and use reaction-induced molecular self-assembling to modify the surface and change ratio to control bio-inert property, we believe this method can provide development of zwitterionzation in the future