51
|
Chan HSO, Ng SC, Sim WS, Tan KL, Tan BTG. Preparation and characterization of electrically conducting copolymers of aniline and anthranilic acid: evidence for self-doping by x-ray photoelectron spectroscopy. Macromolecules 2002. [DOI: 10.1021/ma00048a026] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
52
|
Neoh KG, Kang ET, Tan KL. Structural investigations of aromatic amine polymers. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100195a046] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
53
|
Chan HSO, Ng SC, Sim WS, Seow SH, Tan KL, Tan BTG. Synthesis and characterization of conducting poly(o-aminobenzyl alcohol) and its copolymers with aniline. Macromolecules 2002. [DOI: 10.1021/ma00053a022] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
54
|
Kang ET, Neoh KG, Tan TC, Khor SH, Tan KL. Structural studies of poly(p-phenyleneamine) and its oxidation. Macromolecules 2002. [DOI: 10.1021/ma00213a018] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
55
|
Neoh KG, Kang ET, Tan KL. Structural study of polyaniline films in reprotonation/deprotonation cycles. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100177a094] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
56
|
Chan HSO, Ho PKH, Ng SC, Tan BTG, Tan KL. A New Water-Soluble, Self-Doping Conducting Polyaniline from Poly(o-aminobenzylphosphonic acid) and Its Sodium Salts: Synthesis and Characterization. J Am Chem Soc 2002. [DOI: 10.1021/ja00138a004] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
57
|
Kang ET, Neoh KG, Ong YK, Tan KL, Tan BTG. X-ray photoelectron spectroscopic studies of polypyrrole synthesized with oxidative iron(III) salts. Macromolecules 2002. [DOI: 10.1021/ma00010a028] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
58
|
Lin J, Neoh KG, Li N, Tan TC, Wee ATS, Huan ACH, Tan KL. The interaction between carbon monoxide and yttrium barium copper oxide, YBa2Cu3Ox, as studied by TG/DTA, FTIR, and XPS. Inorg Chem 2002. [DOI: 10.1021/ic00066a021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
59
|
Tan KL, Woon LL, Wong HK, Kang ET, Neoh KG. Surface modification of plasma-pretreated poly(tetrafluoroethylene) films by graft copolymerization. Macromolecules 2002. [DOI: 10.1021/ma00063a030] [Citation(s) in RCA: 247] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
60
|
Zhang F, Kang ET, Neoh KG, Wang P, Tan KL. Reactive coupling of poly(ethylene glycol) on electroactive polyaniline films for reduction in protein adsorption and platelet adhesion. Biomaterials 2002; 23:787-95. [PMID: 11771698 DOI: 10.1016/s0142-9612(01)00184-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly(ethylene glycol) (PEG)-coupled polyaniline (PANI) film surfaces were prepared by incorporating the chlorinie end-capped methoxy PEG (mPEGCl) of molecular weight of about 2000 onto the emeraldine (EM) base form of PANI via N-alkylation. The microstructure and composition of the mPEG-coupled PANI (mPEG-c-PANI) surfaces were characterized by atomic force microscopy, contact angle measurement and X-ray photoelectron spectroscopy. The concentration of surface-coupled mPEG increased with the increase in concentration of the mPEGCl solution. The mPEG-c-PANI film surfaces exhibited enhanced ability to repel protein adsorption, with only an moderate reduction in their electrical conductivity. The mPEG-c-PANI surface with a high concentration of coupled mPEG also exhibited good resistance towards platelet adhesion.
Collapse
|
61
|
Siddle A, Castle JE, Hultquist G, Tan KL. Investigation of the initial reaction of the alloy Co86Cr14 and its constituent metals with oxygen using secondary ion mass spectrometry. SURF INTERFACE ANAL 2002. [DOI: 10.1002/sia.1457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
62
|
Tan KL, Tan JA, Wong YC, Wee YC, Thong MK, Yap SF. Combine-ARMS: a rapid and cost-effective protocol for molecular characterization of beta-thalassemia in Malaysia. GENETIC TESTING 2001; 5:17-22. [PMID: 11336396 DOI: 10.1089/109065701750168626] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Beta-thalassemia major patients have chronic anemia and are dependent on blood transfusions to sustain life. Molecular characterization and prenatal diagnosis of beta3-thalassemia is essential in Malaysia because about 4.5% of the population are heterozygous carriers for beta-thalassemia. The high percentage of compound heterozygosity (47.62%) found in beta-thalassemia major patients in the Thalassaemia Registry, University of Malaya Medical Centre (UMMC), Malaysia, also supports a need for rapid, economical, and sensitive protocols for the detection of beta-thalassemia mutations. Molecular characterization of beta-thalassemia mutations in Malaysia is currently carried out using ARMS, which detects a single beta-thalassemia mutation per PCR reaction. We developed and evaluated Combine amplification refractory mutation system (C-ARMS) techniques for efficient molecular detection of two to three beta-thalassemia mutations in a single PCR reaction. Three C-ARMS protocols were evaluated and established for molecular characterization of common beta-thalassemia mutations in the Malay and Chinese ethnic groups in Malaysia. Two C-ARMS protocols (cd 41-42/IVSII #654 and -29/cd 71-72) detected the beta-thalassemia mutations in 74.98% of the Chinese patients studied. The CARMS for cd 41-42/IVSII #654 detected beta-thalassemia mutations in 72% of the Chinese families. C-ARMS for cd 41-42/IVSI #5/cd 17 allowed detection of beta-thalassemia mutations in 36.53% of beta-thalassemia in the Malay patients. C-ARMS for cd 41-42/IVSI #5/cd 17 detected beta-thalassemia in 45.54% of the Chinese patients. We conclude that C-ARMS with the ability to detect two to three mutations in a single reaction provides more rapid and cost-effective protocols for beta-thalassemia prenatal diagnosis and molecular analysis programs in Malaysia.
Collapse
|
63
|
Yang GH, Kang ET, Neoh KG, Zhang Y, Tan KL. Electroless deposition of copper on polyimide films modified by surface graft copolymerization with nitrogen-containing vinyl monomers. Colloid Polym Sci 2001. [DOI: 10.1007/s003960100485] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
64
|
Zhang F, Kang ET, Neoh KG, Wang P, Tan KL. Surface modification of stainless steel by grafting of poly(ethylene glycol) for reduction in protein adsorption. Biomaterials 2001; 22:1541-8. [PMID: 11374453 DOI: 10.1016/s0142-9612(00)00310-0] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The surface of stainless steel was first modified by the silane coupling agent (SCA), (3-mercaptopropyl)trimethoxysilane. The silanized stainless-steel surface (SCA-SS surface) was subsequently activated by argon plasma and then subjected to UV-induced graft polymerization of poly(ethylene glycol)methacrylate (PEGMA). The chemical structures and composition of the pristine, silane-treated, plasma-treated and PEGMA graft-polymerized stainless-steel coupon surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. The graft polymerization of PEGMA onto the plasma-pretreated SCA-SS surface was studied with different argon plasma pretreatment time, macromonomer concentration, and UV graft polymerization time. In general, a brief plasma pretreatment, high PEGMA concentration, and long UV graft polymerization time readily resulted in a high graft concentration. The PEGMA graft-polymerized stainless-steel coupon (PEGMA-g-SCA-SS) with a high graft concentration, and thus a high PEG content, was found to be very effective in preventing bovine serum albumin and gamma-globulin adsorption.
Collapse
|
65
|
Ng SW, Neoh KG, Sampanthar JT, Kang ET, Tan KL. Conversion of Polyaniline from Insulating to Conducting State in Aqueous Viologen Solutions. J Phys Chem B 2001. [DOI: 10.1021/jp002669y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
66
|
Cheo SH, Wang P, Tan KL, Ho CC, Kang ET. Surface modification of natural rubber latex films via grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2001; 12:377-384. [PMID: 15348275 DOI: 10.1023/a:1011280416520] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Natural rubber (NR) latex films with surface grafted poly(ethylene glycol) (PEG) chains were prepared by UV-induced graft copolymerization of methoxy poly(ethylene glycol) monomethacrylate (PEGMA) onto the plasma-pretreated NR latex films. PEGMA macromononers of different molecular weights were used. The UV-induced graft copolymerization of PEGMA onto the plasma-pretreated NR latex films was also explored with PEGMA of different macromonomer concentrations and with different UV graft copolymerization time. The surface microstructures and compositions of the PEG-modified NR latex films were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. In general, higher macromonomer concentration and longer UV graft copolymerization time led to a higher graft yield. Water contact angle measurements revealed that the hydrophilicity of the NR latex film surface was greatly enhanced by the grafting of the PEG chains. The NR surface with a high density of grafted PEG was very effective in reducing protein adsorption and platelet adhesion. A lower graft concentration of the high-molecular-weight PEG was more effective than a high graft concentration of the low-molecular-weight PEG in reducing protein adsorption and platelet adhesion.
Collapse
|
67
|
Chen Y, E. T. Kang,* and, Neoh KG, Tan KL. Oxidative Graft Polymerization of Aniline on Modified Si(100) Surface. Macromolecules 2001. [DOI: 10.1021/ma0008589] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
68
|
Tan KL, Bergman RG, Ellman JA. Annulation of alkenyl-substituted heterocycles via rhodium-catalyzed intramolecular C-H activated coupling reactions. J Am Chem Soc 2001; 123:2685-6. [PMID: 11456947 DOI: 10.1021/ja0058738] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
69
|
Chen Y, Kang ET, Neoh KG, Ma ZH, Tan KL. Water-Soluble Polyaniline fromγ-Ray-InducedN-Acylation Graft Copolymerization with Acrylic Acid in the Emeraldine State. MACROMOL CHEM PHYS 2001. [DOI: 10.1002/1521-3935(20010301)202:6<785::aid-macp785>3.0.co;2-c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
70
|
Zou XP, Kang ET, Neoh KG, Zhang Y, Tan KL, Cui CQ, Lim TB. Plasma polymerization and deposition of glycidyl methacrylate on Si(100) surface for adhesion improvement with polyimide. POLYM ADVAN TECHNOL 2001. [DOI: 10.1002/pat.146] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
71
|
Tan KL, Crossland WA, Mears RJ. Dynamic holography for optical interconnections. I. Noise floor of low-cross-talk holographic switches. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2001; 18:195-204. [PMID: 11151998 DOI: 10.1364/josaa.18.000195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Reconfigurable optical interconnects constructed by recording dynamic holograms onto spatial light modulators may be crucial elements in all-optical networks. The extremely low cross-talk level of such free-space holographic switches was shown by an analytic approximation and verified experimentally. The fiber-to-fiber switch utilizes the spatial filtering properties of single-mode fibers, and its cross-talk noise is limited to the sidelobe power as a result of diffraction of the clipped Gaussian beam at the hologram aperture edges, provided that all higher orders are avoided. Greater than 45-dB cross-talk isolation has been measured at transverse-axis locations, and locating a fiber port at off-transverse-axis directions promises to double this level if aberrations are negligible.
Collapse
|
72
|
Lim VWL, Kang ET, Neoh KG, Tan KL. Lamination of conductive polypyrrole films to poly(tetrafluoroethylene) films via interfacial graft copolymerization. J Appl Polym Sci 2001. [DOI: 10.1002/1097-4628(20010502)80:5<716::aid-app1148>3.0.co;2-f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
73
|
Zhang F, Kang ET, Neoh KG, Wang P, Tan KL. Modification of Si(100) surface by the grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion. ACTA ACUST UNITED AC 2001; 56:324-32. [PMID: 11372049 DOI: 10.1002/1097-4636(20010905)56:3<324::aid-jbm1100>3.0.co;2-p] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The modification of argon plasma-pretreated single-crystal Si(100) wafer surfaces via the UV-induced graft polymerization of poly(ethylene glycol) methacrylate (PEGMA) macromonomer (molecular weight approximately 340) for biomaterials applications was explored. The modified Si(100) surfaces were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. Surface peroxide concentrations resulting from the argon plasma treatment and subsequent atmospheric exposure were determined by a coupling reaction with diphenylpicrylhydrazyl. The results suggested that a short plasma treatment time of 10 s and brief air exposure were sufficient for generating an optimum amount of peroxides and hydroperoxides for the subsequent UV-induced graft polymerization. The graft concentration of the PEGMA polymer increased with increasing PEGMA macromonomer concentration for the graft polymerization and with increasing UV graft polymerization time. The PEGMA graft-polymerized silicon surface with a high poly(ethylene glycol) graft concentration was very effective in preventing protein adsorption and platelet adhesion. The grafted PEGMA polymer layer on the Si(100) surface exhibited fairly good stability during storage in a buffer solution.
Collapse
|
74
|
Wang P, Tan KL, Kang ET, Neoh KG. Synthesis, characterization and anti-fouling properties of poly(ethylene glycol) grafted poly(vinylidene fluoride) copolymer membranes. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b007310p] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
75
|
Tan KL, Warr ST, Manolis IG, Wilkinson TD, Redmond MM, Crossland WA, Mears RJ, Robertson B. Dynamic holography for optical interconnections. II. Routing holograms with predictable location and intensity of each diffraction order. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2001; 18:205-215. [PMID: 11151999 DOI: 10.1364/josaa.18.000205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An analysis of dynamic phase-only holograms, described by fractional notation and recorded onto a pixelated spatial light modulator (SLM) in a reconfigurable optical beam-steering switch, is presented. The phase quantization and arrangement of the phase states and the SLM pixelation and dead-space effects are decoupled, expressed analytically, and simulated numerically. The phase analysis with a skip-rotate rule reveals the location and intensity of each diffraction order at the digital replay stage. The optical reconstruction of the holograms recorded onto SLM's with rectangular pixel apertures entails sinc-squared scaling, which further reduces the intensity of each diffraction order. With these two factors taken into account, the highest values of the nonuniform first-order diffraction efficiencies are expected to be 33%, 66%, and 77% for two-, four-, and and eight-level one-dimensional holograms with a 90% linear pixel fill factor. The variation of the first-order diffraction efficiency and the relative replay intensities were verified to within 1 dB by performing the optical reconstruction of binary phase-only holograms recorded onto a ferroelectric liquid crystal on a silicon SLM.
Collapse
|