DOCSLIB.ORG

(PDMS) Properties for Biomedical Micro/Nanosystems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(PDMS) Properties for Biomedical Micro/Nanosystems Biomedical Microdevices 7:4, 281–293, 2005 C 2005 Springer Science + Business Media, Inc. Manufactured in The Netherlands. Characterization of Polydimethylsiloxane (PDMS) Properties for Biomedical Micro/Nanosystems Alvaro Mata,1,2 Aaron J. Fleischman,2 and Shuvo Roy2,∗ 1Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH 44115 2BioMEMS Laboratory, Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44120 E-mail: [email protected] Abstract. Polydimethylsiloxane (PDMS SylgardR 184, Dow Corn- search and development of MEMS-based devices in the ing Corporation) pre-polymer was combined with increasing biomedical arena for a variety of applications ranging amounts of cross-linker (5.7, 10.0, 14.3, 21.4, and 42.9 wt.%) and from diagnostics (Fujii, 2002; Mastrangelo et al., 1998; designated PDMS1, PDMS2, PDMS3, PDMS4, and PDMS5,respec- tively. These materials were processed by spin coating and subjected Paranjape et al., 2003; Wu et al., 2001) to therapeutics to common microfabrication, micromachining, and biomedical pro- (Borenstein et al., 2002; Chung et al., 2003; Ferrara et al., cesses: chemical immersion, oxygen plasma treatment, sterilization, 2003; Santini et al., 1999; Tao and Desai, 2003). However, and exposure to tissue culture media. The PDMS formulations were the development of these applications through established analyzed by gravimetry, goniometry, tensile testing, nanoindenta- MEMS manufacturing approaches is hindered by inherent tion, scanning electron microscopy (SEM), Fourier transform in- frared spectroscopy (FTIR), and X-ray photoelectron spectroscopy characteristics of traditional silicon-based processes such (XPS). Spin coating of PDMS was formulation dependent with film as high costs and limited access to clean room environ- thickness ranging from 308 µmonPDMS1 to 171 µmonPDMS5 ments (Roy et al., 2001; Whitesides et al., 2001). More- at 200 revolutions per minute (rpm). Ultimate tensile stress (UTS) over, the most successful silicon-based microfabrication increased from 3.9 MPa (PDMS1)to10.8 MPa (PDMS3), and then process has been photolithography, which is expensive, decreased down to 4.0 MPa (PDMS5). Autoclave sterilization (AS) increased the storage modulus (σ) and UTS in all formulations, with works for a limited set of materials, and is often limited the highest increase in UTS exhibited by PDMS5 (218%). PDMS sur- to planar surfaces (Deng et al., 2000; Quake and Scherer, face hydrophilicity and micro-textures were generally unaffected 2000; Xia and Whitesides, 1998). when exposed to the different chemicals, except for micro-texture The diversity of applications and commercialization of changes after immersion in potassium hydroxide and buffered hy- MEMS has encouraged the MEMS community to find pro- drofluoric, nitric, sulfuric, and hydrofluoric acids; and minimal changes in contact angle after immersion in hexane, hydrochloric cesses and materials that enable mass production while re- acid, photoresist developer, and toluene. Oxygen plasma treatment ducing costs. Likewise, the increasing number of biomed- decreased the contact angle of PDMS2 from 109◦ to 60◦. Exposure ical MEMS (BioMEMS) applications has led to a diver- to tissue culture media resulted in increased PDMS surface element gence from traditional silicon-based processing, and the concentrations of nitrogen and oxygen. pursuit of more biologically friendly materials. New fab- KeyWords. polydimethylsiloxane, PDMS, Poly(dimethylsiloxane), rication techniques such as Soft Lithography have fos- mechanical properties, micromachining, microfabrication, MEMS, tered the use of biocompatible materials such as polymers microsystems, contact angle, sterilization, tensile strength, struc- (Whitesides et al., 2001; Xia and Whitesides, 1998). The tural properties, nanotechnology, nanosystems practicability of polymers for fabrication with both rapid prototyping and mass production techniques as well as lower cost relative to silicon and glass make them partic- 1. Introduction ularly attractive for the development of BioMEMS (Deng et al., 2000; Quake and Scherer, 2000). Polycarbonate Recent advances in microelectromechanical systems (PC), polymethylmethacrylate (PMMA), polyvinylchlo- (MEMS) technology are providing new opportunities for ride (PVC), polyethylene (PE), and polydimethylsiloxane avariety of biological and medical applications (Bashir, (PDMS) are some of the polymer candidates for the low 2004; Rebello, 2004; Roy et al., 2001; Ziaie et al., 2004). cost, mass production of BioMEMS devices (Despa et al., Microfabrication and micromachining-based approaches 1999; Duffy et al., 1998; Lee et al., 2001; Lin et al., 1998; offer the potential to tackle biomedical problems within Weietal., 2005). the same size scale of cells and subcellular structures (Desai, 2000; Itoh, 1999; Kane et al., 1999; Mata et al., 2003). Consequently, there has been an increase in re- ∗Corresponding author. 281 282 Mata, Fleischman and Roy PDMS is a silicone elastomer with desirable properties and PDMS5, corresponding to 5.7, 10.0, 14.3, 21.4, and that make it attractive for the development of MEMS and 42.9 wt.% cross-linker, respectively. The different PDMS microfluidics components for biomedical applications (Jo formulations were formulated to investigate possible al- et al., 2000; Mata et al., 2002b; McDonald and White- terations in PDMS properties due to deviation from the sides, 2002; Unger et al., 2000). It is chemically inert, recommended 10:1 weight ratio, which corresponds to thermally stable, permeable to gases, simple to handle our PDMS2 notation. and manipulate, exhibits isotropic and homogeneous prop- The surface and structural properties of the different erties as well as lower cost than silicon, and can con- PDMS formulations were analyzed to investigate the ef- form to submicron features to develop microstructures fects of common biomedical, microfabrication, and mi- (McDonald and Whitesides, 2002; Ng et al., 2002; Xia and cromachining processes including: (a) spin coating—to Whitesides, 1998). The use of PDMS for BioMEMS appli- quantify the effect of the amount of cross-linker on thick- cations has been largely driven by the development of Soft ness profiles; (b) chemical immersion—to characterize Lithography techniques such as micro-contact printing, and quantify the effect of various chemicals used in micro- replica molding, micro-transfer molding, micro-molding fabrication and micromachining on both surface micro- in capillaries, and solvent-assisted micro-molding (Xia texture degradation and long-term surface hydrophilic- and Whitesides, 1998). These techniques usually require ity; (c) exposure to oxygen plasma—to quantify its effect the use of PDMS to create an elastomeric stamp or mold on long-term surface hydrophilicity; (d) sterilization—to that incorporates microstructures for transfer of patterns characterize and quantify the effect of various sterilization onto a subsequent substrate. In addition, PDMS is trans- procedures on surface micro-texture degradation, long- parent, non-fluorescent, biocompatible and nontoxic, and term surface hydrophilicity, surface chemical composi- has been traditionally used as a biomaterial in catheters, tion, and mechanical properties; and (e) exposure to tis- drainage tubing, insulation for pacemakers, membrane sue culture media—to characterize changes in the surface oxygenators, and ear and nose implants (Visser et al., chemical composition. The PDMS formulations were an- 1996). alyzed by gravimetry, goniometry, tensile testing, nanoin- The extensive biomaterial foundation of PDMS in dentation, scanning electron microscopy (SEM), X-ray conjunction with the increasing interest in low cost, photoelectron spectroscopy (XPS), and Fourier Transform mass-produced, microfabrication compatible, polymeric Infrared Spectroscopy (FTIR). Statistical significance was MEMS make it formidable and promising material for defined at the 95% confidence interval using a One Way current and future BioMEMS applications. Consequently, Analysis of Variance (ANOVA) test performed in Sigma- there is significant interest in examining the compatibil- Stat Statistical Software Version 2.0 (SPSS, Chicago, IL). ity of PDMS with both MEMS technology and biomedical A summary of the various processes and respective anal- applications. Therefore, we investigated the structural and ysis tools is presented in Table 1. It should be noted that surface properties of SylgardR 184 (Dow Corning Corpo- not all PDMS formulations were investigated for effects ration, Midland, MI), which is a widely used commer- of the different processes. The basis for choice of specific cially available brand of PDMS. This paper reports on the PDMS formulations for certain processes was based on effects of various biomedical, microfabrication, and mi- equipment availability. Nevertheless, PDMS2 was used in cromachining processes on the characteristics of PDMS all investigations since it is the standard formulation rec- SylgardR 184. More specifically, this paper attempts to ommended by the manufacturer. convey relevant information on particular properties of PDMS that will accelerate its wider adoption for the de- velopment of BioMEMS devices and applications. 2.2. Processes Spin coating. Spin coating is a common microfabrica- tion method for producing polymer films of controlled and 2. Materials and Methods uniform thickness (Linderholm and Asberg, 2000; Lotters et al.,
Load more

Recommended publications
  • Federal Register/Vol. 70, No. 216/Wednesday
    Federal Register / Vol. 70, No. 216 / Wednesday, November 9, 2005 / Notices 68037 OPP–2005–0173. The official public TABLE 2.—REGISTRANT OF AMENDED effective date of the order to terminate docket consists of the documents PRODUCT use. The order issued in this Notice specifically referenced in this action, includes the following existing stocks any public comments received, and EPA Company Company Name and Ad- provisions. other information related to this action. No. dress Products in the United States that have been packaged, labeled, and Although a part of the official docket, 2596 The Hartz Mountain Cor- the public docket does not include released for shipment prior to the poration, 400 Plaza effective date of the order terminating Confidential Business Information (CBI) Drive Secaucus, NJ or other information whose disclosure is 07094–3688 use on cats and kittens may be sold or restricted by statute. The official public distributed by Hartz from its facilities until December 31, 2005. After docket is the collection of materials that III. Summary of Public Comments December 31, 2005, Hartz may not sell is available for public viewing at the Received and Agency Response to or distribute product labeled for use on Public Information and Records Comments cats and kittens. Products labeled for Integrity Branch (PIRIB), Rm. 119, During the public comment period use on cats and kittens may be sold or Crystal Mall #2, 1801 S. Bell St., provided, EPA received no comments in distributed by persons other than the Arlington, VA. This docket facility is response to the July 20, 2005 Federal registrant until March 31, 2006.
    [Show full text]
  • Polydimethylsiloxane Emulsion
    DMS-T31M50 - POLYDIMETHYLSILOXANE EMULSION POLYDIMETHYLSILOXANE EMULSION Safety Data Sheet DMS-T31M50 Date of issue: 04/28/2016 Version: 1.0 SECTION 1: Identification of the substance/mixture and of the company/undertaking 1.1. Product identifier Product form : Mixture Physical state : Liquid Product name : POLYDIMETHYLSILOXANE EMULSION Product code : DMS-T31M50 Synonyms : POLY(DIMETHYLSILOXANE), TRIMETHYLSILOXY TERMINATED, emulsion; SILICONE OIL EMULSION Chemical family : ORGANOSILOXANE 1.2. Relevant identified uses of the substance or mixture and uses advised against Use of the substance/mixture : Chemical intermediate For research and industrial use only 1.3. Details of the supplier of the safety data sheet GELEST, INC. 11 East Steel Road Morrisville, PA 19067 USA T 215-547-1015 - F 215-547-2484 - (M-F): 8:00 AM - 5:30 PM EST [email protected] - www.gelest.com 1.4. Emergency telephone number Emergency number : CHEMTREC: 1-800-424-9300 (USA); +1 703-527-3887 (International) SECTION 2: Hazards identification 2.1. Classification of the substance or mixture GHS-US classification Not classified 2.2. Label elements GHS-US labeling No labeling applicable 2.3. Other hazards No additional information available 2.4. Unknown acute toxicity (GHS US) No data available SECTION 3: Composition/Information on ingredients 3.1. Substance Not applicable 3.2. Mixture Name Product identifier % GHS-US classification Polydimethylsiloxane (CAS No) 9016-00-6/63148-62-9 45 - 50 Not classified Water (CAS No) 7732-18-5 45 - 50 Not classified Polyoxyethylene(20)sorbitan monooleate (CAS No) 9005-65-6 1 - 5 Not classified Sorbitan monolaurate (CAS No) 1338-39-2 1 - 5 Not classified SECTION 4: First aid measures 4.1.
    [Show full text]
  • Synthesis of Functionalized Poly(Dimethylsiloxane)S and the Preparation of Magnetite Nanoparticle Complexes and Dispersions
    Synthesis of Functionalized Poly(dimethylsiloxane)s and the Preparation of Magnetite Nanoparticle Complexes and Dispersions Kristen Wilson O’Brien Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Chemistry Approved by: ____________________________ Judy S. Riffle, Chair ____________________________ ____________________________ Alan Esker Jack Lesko ____________________________ ____________________________ Timothy E. Long James E. McGrath August 21, 2003 Blacksburg, Virginia Keywords: Polymers, iron oxides; steric stabilization; magnetic fluids Copyright 2003, Kristen Wilson O’Brien Synthesis of Functionalized Poly(dimethylsiloxane)s and the Preparation of Magnetite Nanoparticle Complexes and Dispersions Kristen Wilson O’Brien (ABSTRACT) Poly(dimethylsiloxane) (PDMS) fluids containing magnetite nanoparticles stabilized with carboxylic acid-functionalized PDMS were prepared. PDMS-magnetite complexes were characterized using transmission electron microscopy, elemental analysis, and vibrating sample magnetometry. PDMS-magnetite complexes containing up to 67 wt% magnetite with magnetizations of ~52 emu gram-1 were prepared. The magnetite particles were 7.4 ± 1.7 nm in diameter. Calculations suggested that the complexes prepared using mercaptosuccinic acid-functionalized PDMS (PDMS-6COOH) complexes contained unbound acid groups whereas the mercaptoacetic acid- functionalized PDMS (PDMS-3COOH) complexes did not.
    [Show full text]
  • Chapter 6 Ecological Health
    Integrated Mosquito Management Program │ Programmatic EIR Table of Contents 6 Ecological Health ..........................................................................................................6-1 6.1 Environmental Setting ...................................................................................................... 6-1 6.1.1 Hazards, Toxicity, and Exposure in the Environmental Setting ........................ 6-1 6.1.2 Pesticides and the Environment ....................................................................... 6-3 6.1.3 Regulatory Setting............................................................................................. 6-4 6.2 Environmental Impacts and Mitigation Measures ............................................................ 6-7 6.2.1 Evaluation Concerns and Criteria ..................................................................... 6-7 6.2.2 Evaluation Methods and Assumptions ............................................................ 6-10 6.2.3 Surveillance Alternative .................................................................................. 6-14 6.2.4 Physical Control Alternative ............................................................................ 6-15 6.2.5 Vegetation Management Alternative ............................................................... 6-16 6.2.6 Biological Control Alternative .......................................................................... 6-19 6.2.7 Chemical Control Alternative .........................................................................
    [Show full text]
  • Nufarm Product Guide
    NUFARM PRODUCT GUIDE FOR VEGETABLES HERBICIDES NUFARM ACTIVE Asian Brussels Asparagus Beans Beetroot Broccoli Cabbage Capsicum Carrots Cauliflower Celery Corn Cucurbits Garlic Ginger Lettuce Mushrooms Onions Parsnip Peas Potatoes Radish Rhubarb Shallots Spinach Squash Tomatoes Turnips PRODUCT INGREDIENT Brassicas Sprouts Amitrole 250g/L and Ammonium thiocyanate 220g/L Atrazine 900g/kg Sweet corn Glufosinate- ammonium 200g/L ® S-Metolachlor Sweet Sweet 960g/L corn potatoes Fluroxypyr 400g/L Sweet corn Chlorthal dimethyl Potatoes & sweet 900g/kg potatoes Diuron 900g/kg Sweet SELECTIVE PRE–EMERGENT EPTC 720g/L HERBICIDE corn Glyphosate 450g/L For weed control prior to sowing crop Glyphosate 680g/L For weed control prior to sowing crop Glyphosate 540g/L For weed control prior to sowing crop Clethodim 240g/L Carfentrazone For weed control prior to sowing crop ethyl 600g/L Prometryn 900g/kg Propachlor 480g/L Sweet corn ® Paraquat 135g/L For weed control prior to sowing crop and Diquat 115g/L ® Paraquat 250g/L For weed control prior to sowing crop Simazine 900g/kg Oxyfluorfen 240g/L Metribuzin 750g/kg Trifluralin 480g/L Glyphosate 540g/L For weed control prior to sowing crop Glyphosate 470g/L For weed control prior to sowing crop Glyphosate 360g/L For weed control prior to sowing crop PLANT GROWTH REGULANTS NUFARM ACTIVE Asian Brussels Asparagus Beans Beetroot Broccoli Cabbage Capsicum Carrots Cauliflower Celery Corn Cucurbits Garlic Ginger Lettuce Mushrooms Onions Parsnip Peas Potatoes Radish Rhubarb Shallots Spinach Squash Tomatoes Turnips
    [Show full text]
  • Hollow Polydimethylsiloxane (PDMS) Foam with a 3D Interconnected Network for Highly Sensitive Capacitive Pressure Sensors
    Kim et al. Micro and Nano Syst Lett (2020) 8:24 https://doi.org/10.1186/s40486-020-00127-8 LETTER Open Access Hollow polydimethylsiloxane (PDMS) foam with a 3D interconnected network for highly sensitive capacitive pressure sensors Dong Hwan Kim1, Young Jung1,3, Kyungkuk Jung4, Dong Hwa Kwak1, Dong Min Park1, Myung Gyu Shin2, Hyeong Jun Tak1 and Jong Soo Ko1* Abstract We propose a highly sensitive capacitive pressure sensor made of hollow polydimethylsiloxane (PDMS) foam with a three-dimensional network structure. The stifness of the foam is adjusted by the viscosity of the PDMS solution. The fabricated PDMS-30 (PDMS 30 wt%) foam shows extremely high porosity (> 86%) approximately 19 times that of bare PDMS (PDMS 100 wt%) foam. Capacitive pressure sensors fabricated using the foam possess high sensitivity, good compressibility (up to 80% strain), and consistent output characteristics in a 2000-cycle test. Keywords: Capacitive pressure sensor, Hollow PDMS foam, Porosity Introduction εr and the distance between the electrodes d are the key Over the last decade, fexible pressure sensors for a vari- factors afecting the performance capabilities of sensors ety of wearable applications, such as electronic skin [1], such as those designed to measure pressure responsive human health monitoring [2, 3], and human–machine sensitivity levels [17]. interfaces [4, 5], have received signifcant attention. Many To ensure the fabrication of high-performance capaci- researchers have concentrated on the development of tive pressure sensors, recent studies have reported that various types of fexible and wearable pressure sensors, microstructured or patterned polydimethylsiloxane including piezoresistive [6, 7], capacitive [8–10], piezo- (PDMS) dielectric layers represent the most efective electric [11, 12], and triboelectric types [13, 14].
    [Show full text]
  • Lindane Bioremediation Capability of Bacteria Associated with the Demosponge Hymeniacidon Perlevis
    marine drugs Article Lindane Bioremediation Capability of Bacteria Associated with the Demosponge Hymeniacidon perlevis Stabili Loredana 1,2,*, Pizzolante Graziano 2, Morgante Antonio 2, Nonnis Marzano Carlotta 3,4, Longo Caterina 3,4, Aresta Antonella Maria 5, Zambonin Carlo 5, Corriero Giuseppe 3,4 and Alifano Pietro 2 1 Istituto per l’Ambiente Marino Costiero, Unità Operativa di Supporto di Taranto, CNR, Via Roma 3, 74123 Taranto, Italy 2 Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Via Prov.le Lecce Monteroni, 73100 Lecce, Italy; [email protected] (P.G.); [email protected] (M.A.); [email protected] (A.P.) 3 Dipartimento di Biologia, Università di Bari Aldo Moro, 70125 Bari, Italy; [email protected] (N.M.C.); [email protected] (L.C.); [email protected] (C.G.) 4 CoNISMa, Piazzale Flaminio 9, 00196 Roma, Italy 5 Dipartimento di Chimica, Università di Bari Aldo Moro, 70125 Bari, Italy; [email protected] (A.A.M.); [email protected] (Z.C.) * Correspondence: [email protected]; Tel.: +39-0832-298971 Academic Editors: Vassilios Roussis, Efstathia Ioannou and Keith B. Glaser Received: 23 January 2017; Accepted: 27 March 2017; Published: 6 April 2017 Abstract: Lindane is an organochlorine pesticide belonging to persistent organic pollutants (POPs) that has been widely used to treat agricultural pests. It is of particular concern because of its toxicity, persistence and tendency to bioaccumulate in terrestrial and aquatic ecosystems. In this context, we assessed the role of bacteria associated with the sponge Hymeniacidon perlevis in lindane degradation.
    [Show full text]
  • Oral, Ultra–Long-Lasting Drug Delivery: Application Toward Malaria Elimination Goals
    Oral, ultra–long-lasting drug delivery: Application toward malaria elimination goals The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Bellinger, Andrew M. et al. "Oral, ultra–long-lasting drug delivery: Application toward malaria elimination goals." 8, 365 (November 2016): 365ra157 © 2016 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. As Published http://dx.doi.org/10.1126/scitranslmed.aag2374 Publisher American Association for the Advancement of Science (AAAS) Version Author's final manuscript Citable link https://hdl.handle.net/1721.1/128845 Terms of Use Creative Commons Attribution-Noncommercial-Share Alike Detailed Terms http://creativecommons.org/licenses/by-nc-sa/4.0/ HHS Public Access Author manuscript Author ManuscriptAuthor Manuscript Author Sci Transl Manuscript Author Med. Author Manuscript Author manuscript; available in PMC 2017 November 16. Published in final edited form as: Sci Transl Med. 2016 November 16; 8(365): 365ra157. doi:10.1126/scitranslmed.aag2374. Oral, ultra–long-lasting drug delivery: Application toward malaria elimination goals Andrew M. Bellinger1,2,3,*, Mousa Jafari1,*, Tyler M. Grant1,3,*, Shiyi Zhang1,*,†, Hannah C. Slater4, Edward A. Wenger5, Stacy Mo1, Young-Ah Lucy Lee1, Hormoz Mazdiyasni1, Lawrence Kogan1, Ross Barman1, Cody Cleveland1,6, Lucas Booth1, Taylor Bensel1, Daniel Minahan1, Haley M. Hurowitz1, Tammy Tai1, Johanna Daily7, Boris Nikolic8, Lowell Wood5, Philip A. Eckhoff5, Robert Langer1,9,10,‡, and Giovanni Traverso1,6,11,‡ 1Department of Chemical Engineering and Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. 2Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA.
    [Show full text]
  • Bulk Drug Substances Nominated for Use in Compounding Under Section 503B of the Federal Food, Drug, and Cosmetic Act
    Updated June 07, 2021 Bulk Drug Substances Nominated for Use in Compounding Under Section 503B of the Federal Food, Drug, and Cosmetic Act Three categories of bulk drug substances: • Category 1: Bulk Drug Substances Under Evaluation • Category 2: Bulk Drug Substances that Raise Significant Safety Risks • Category 3: Bulk Drug Substances Nominated Without Adequate Support Updates to Categories of Substances Nominated for the 503B Bulk Drug Substances List1 • Add the following entry to category 2 due to serious safety concerns of mutagenicity, cytotoxicity, and possible carcinogenicity when quinacrine hydrochloride is used for intrauterine administration for non- surgical female sterilization: 2,3 o Quinacrine Hydrochloride for intrauterine administration • Revision to category 1 for clarity: o Modify the entry for “Quinacrine Hydrochloride” to “Quinacrine Hydrochloride (except for intrauterine administration).” • Revision to category 1 to correct a substance name error: o Correct the error in the substance name “DHEA (dehydroepiandosterone)” to “DHEA (dehydroepiandrosterone).” 1 For the purposes of the substance names in the categories, hydrated forms of the substance are included in the scope of the substance name. 2 Quinacrine HCl was previously reviewed in 2016 as part of FDA’s consideration of this bulk drug substance for inclusion on the 503A Bulks List. As part of this review, the Division of Bone, Reproductive and Urologic Products (DBRUP), now the Division of Urology, Obstetrics and Gynecology (DUOG), evaluated the nomination of quinacrine for intrauterine administration for non-surgical female sterilization and recommended that quinacrine should not be included on the 503A Bulks List for this use. This recommendation was based on the lack of information on efficacy comparable to other available methods of female sterilization and serious safety concerns of mutagenicity, cytotoxicity and possible carcinogenicity in use of quinacrine for this indication and route of administration.
    [Show full text]
  • Polydimethylsiloxane Containing Block Copolymers
    POLYDIMETHYLSILOXANE CONTAINING BLOCK COPOLYMERS: SYNTHESIS AND CHARACTERIZATION OF ALTERNATING POLY(ARYLENE ETHER PHOSPHINE OXIDE)-b-SILOXANE AND SEGMENTED NYLON 6,6 –b-SILOXANE COPOLYMERS by W. David Polk Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University In partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Chemistry Dr. James E. McGrath, Chairman Dr.JudyS.Riffle Dr.AllanR.Shultz Dr. John G. Dillard Dr.PaulA.Deck July 2, 2001 Blacksburg, Virginia Keywords: Polydimethylsiloxane, Polyarylene Ether, Phenyl Phosphine Oxide, Polyamide, Nylon 6,6, Block Copolymer, Fire Resistance, Optical Materials, Nanoparticles Copyright 2001, W. David Polk POLY(DIMETHYLSILOXANE) CONTAINING BLOCK COPOLYMERS: SYNTHESIS AND CHARACTERIZATION OF ALTERNATING POLY(ARYLENE ETHER PHOSPHINE OXIDE)-B-SILOXANE AND SEGMENTED NYLON 6,6-B- SILOXANE COPOLYMERS W. David Polk (ABSTRACT) Two novel classes of siloxane containing, organic-inorganic block copolymers were prepared using different synthetic approaches. The first copolymers were alternating poly(arylene ether phosphine oxide)-poly(dimethylsiloxane) systems, prepared via oligomeric silylamine-hydroxyl reactions. Secondly, segmented nylon 6,6- poly(dimethylsiloxane) block copolymers were synthesized via a non-aqueous adaptation of the “nylon 6,6 salt” hydrolytic polyamidization, using bis(aminopropyl) dimethylsiloxane oligomer as a co-reactant. Three series of “perfectly” alternating block copolymers were produced from well characterized hydroxyl-terminated poly(arylene ether phosphine oxide) and dimethylamine-terminated poly(dimethylsiloxane) oligomers, in order to investigate both block length and chemical composition effects. Copolymerization in chlorobenzene resulted in high molecular weight materials capable of forming optically clear, nanophase separated films, which displayed unusual morphologies and good mechanical strength.
    [Show full text]
  • Polydimethylsiloxane-Titania Nanocomposite Coating: Fabrication and Corrosion Resistance
    Polymer 138 (2018) 203e210 Contents lists available at ScienceDirect Polymer journal homepage: www.elsevier.com/locate/polymer Polydimethylsiloxane-titania nanocomposite coating: Fabrication and corrosion resistance Xiaokun Cui a, Guiyu Zhu a, Yufeng Pan a, Qian Shao b, Cindy (xinxin) Zhao c, * ** Mengyao Dong c, d, Yue Zhang a, , Zhanhu Guo c, a Institute of Material Science and Engineering, Ocean University of China, Qingdao, Shandong, 266100 PR China b College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, PR China c Integrated Composites Laboratory (ICL), Department of Chemical Engineering, University of Tennessee, Knoxville, TN 37996, USA d National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, PR China article info abstract Article history: Titania (TiO2) nanoparticles were added to polydimethylsiloxane (PDMS) matrix to form nanocomposite Received 9 December 2017 coating via spin coating method on the AA 2024 (one of the aluminum alloys) to improve the anticor- Received in revised form rosion ability of metal. The microstructures of the PDMS/TiO2 composite coating were detected by 11 January 2018 scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometry to verify the Accepted 22 January 2018 structure of composite coating. The corrosion properties of PDMS/TiO composite coating was evaluated Available online 3 February 2018 2 by the electrochemical tests. The results showed that the anticorrosion ability of the composite coating has been significantly affected by the TiO2 content. For example, the impedance modulus value reached Keywords: 6 2 10 Ucm of the composite coating with 8 wt % nano-TiO2 fillers. Meanwhile, the corrosion current PDMS/TiO2 Corrosion resistance density (Icorr) of the coating was smaller than that of bare aluminum.
    [Show full text]
  • Polydimethylsiloxane
    POLYDIMETHYLSILOXANE Prepared at the 37th JECFA (1990), published in FNP 52 (1992) superseding specifications prepared at the 29th JECFA (1985), published in FNP 34 (1986). Metals and arsenic specifications revised at the 61st JECFA (2003). An ADI of 0-1.5 mg/kg bw was established at the 23rd JECFA (1979) SYNONYMS Poly(dimethylsiloxane), dimethylpolysiloxane, dimethylsilicone fluid, dimethylsilicone oil; INS No. 900 DEFINITION Consists of fully methylated linear siloxane polymers containing repeating units of the formula (CH3)2SiO, with trimethylsiloxy end-blocking units of the formula (CH3)3SiO- The article of commerce used as an antifoaming agent can be further specified as to total silicon Chemical names Simethicone (CAS name) C.A.S. number 8050-81-5 Structural formula The average value for n is 90 to 410 Formula weight 6,800 to 30,000 (average and approximate) Assay Silicon content not less than 37.3% and not more than 38.5% of the total DESCRIPTION Clear, colourless, viscous liquid. Polydimethylsiloxane is frequently used in commerce as such, as a liquid containing 4-5% silica gel, and as an aqueous emulsion formulation containing, in addition to silica gel, emulsifiers and preservatives. The pure substance described here can be isolated by centrifuging from the silica gel-containing liquid at about 20,000 rpm. FUNCTIONAL USES Antifoaming agent, anticaking agent CHARACTERISTICS IDENTIFICATION Solubility (Vol. 4) Insoluble in water and in ethanol; soluble in carbon tetrachloride, benzene, chloroform, diethyl ether, toluene and other organic solvents Specific gravity (Vol. 4) d (25, 25): 0.964 - 0.977 Refractive index (Vol. 4) n (25, D): 1.400 - 1.405 Infrared absorption The infrared spectrum of the sample corresponds with the reference infrared spectrum below.
    [Show full text]