DOCSLIB.ORG

Hollow Polydimethylsiloxane (PDMS) Foam with a 3D Interconnected Network for Highly Sensitive Capacitive Pressure Sensors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read 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]. In par- means of improving the sensitivity of the capacitive- ticular, capacitive-type pressure sensors show signifcant type sensors due to their excellent elasticity and bio- advantages given their high sensitivity, low power con- compatibility [18, 19]. Pyramidal [20, 21], micro-pillar sumption, simple design, and low hysteresis [15, 16]. A [22, 23], micro-wrinkle [24, 25], and microdome [26, parallel-plate capacitive sensor is composed of a dielec- 27] shapes created with elastic materials reportedly ofer tric layer sandwiched between two conductive electrode high sensitivity for use as electronic skin. However, the plates for the detection of capacitance changes. With fabrication of a Si microstructured mold is complicated, these sensors, the capacitance parameters change when with signifcant dependence on the equipment, multiple external pressure is applied to the dielectric layer, with necessary steps, and high-cost manufacturing processes. the result ultimately refected in the change of the capaci- Additionally, these sensors operate mainly at a low tance of the sensor. Specifcally, the relative permittivity measurement level (< 10 kPa), which is insufcient for wearable systems in the medium–high pressure regime (10–100 kPa, suitable for object manipulation), as such *Correspondence: [email protected] 1 Graduate School of Mechanical Engineering, Pusan National University, systems must be capable of detecting changes [8]. Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 46241, Republic For these reasons, the 3D monolithic porous PDMS of Korea dielectric layer has attracted much attention for use Full list of author information is available at the end of the article © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. Kim et al. Micro and Nano Syst Lett (2020) 8:24 Page 2 of 7 in capacitive-type pressure sensors [9]. Chhetry et al. synergy efect of the high elasticity of the PDMS elas- reported a pressure sensor based on a dielectric hybrid tomer and the highly porous 3D micro-hollow network sponge consisting of calcium copper titanate (CCTO), a structure, the as-prepared highly porous PDMS dielectric material with very high dielectric permittivity, encased in layer showed excellent mechanical resilience, extremely polyurethane (PU) for detection in low-pressure regime high compressibility, and stable cyclic performance. (< 1.6 kPa) [28]. Pruvost et al. also suggested a PDMS Tese fexible pressure sensors are also capable of not foam decorated with carbon black particles for use in the only detecting low pressure levels but also enabling real- fabrication of highly sensitive capacitive pressure sensors time human motion sensing applications. exceeding 35 kPa−1 for pressures of < 0.2 kPa [29]. Tese studies focused on improving performance capabilities Preparation of the hollow PDMS foam and the pressure via the use of conductive nanomaterials while main- sensor taining the porosity of the sponge. However, aggrega- Figure 1 shows a schematic of the fabrication process of tion and agglomeration cause low production reliability the PDMS foam for the capacitive pressure sensor. Com- of composites of nanomaterials and elastomers, and the mercial copper foam (supplied by ITASCO) with poros- methods above cannot regulate or tune sensor sensitiv- ity of approximately 95% was used as template. First, a ity levels. Te easiest and fastest way to tune a sensor PDMS precursor (Sylgard 184 Silicone Elastomer, Dow without conductive nanomaterials is to adjust its poros- Corning) consisting of a mixture of a resin and a hard- ity. Tus, many studies have focused on high sensitivity ener at a 5:1 ratio was prepared and placed in a vacuum and wide sensing ranges when applying a porous elasto- chamber for 20 min to remove bubbles. In this case, a mer to a capacitive pressure sensor. Kang et al. suggested PDMS diluent (OS-10, Sylgard 184, Dow Corning Corp., a capacitive pressure sensor with a porous structure USA) is used to adjust the porosity of the PDMS foam. consisting of a polydimethylsiloxane (PDMS) thin flm PDMS solution samples of 30 and 50 wt% in terms of the dielectic layer. Te morphology of the porous structured PDMS diluent were created by adding set amounts of the dielectric layer could be controlled by changing the pore PDMS diluent to the PDMS precursor mixture, followed sizes [30]. Jung et al. showed that a PDMS and micro- by ultrasonication for 30 min. Here, PDMS foam samples sphere composite could be applied to a capacitive pres- with diferent porosity levels are denoted as PDMS-x, sure sensor by maximizing the porosity of microspheres where x denotes the weight percentage (wt%) of PDMS via the efect of high compressibility and an enhanced in the immersion solution. Te porosity of the PDMS piezocapacitive efect [9]. Li et al. also reported a pres- dielectric layer in the fabricated pressure sensors was sure sensor based on a dielectric layer of PDMS with controlled by changing the weight percentage of PDMS uniformly distributed micropores which displayed high in the immersion solution. elasticity, a wide pressure-sensing range (> 200 kPa), and In order to remove impurities remaining on the copper high sensitivity (0.023 kPa−1) [31]. surface, the copper foam is rinsed with acetone, ethanol, In this report, we propose a facile approach by which and deionized water. After drying for 30 min in an oven to adjust the porosity of PDMS foam by controlling the at 60 °C, the copper foam was then soaked in a diluted viscosity of the PDMS immersion solution. Due to the PDMS solution (30, 50 wt%) for an hour to ensure a Fig. 1 Schematic illustration of the fabrication process of the porous structured capacitive pressure sensor using copper foam as a template Kim et al. Micro and Nano Syst Lett (2020) 8:24 Page 3 of 7 conformal coating, after which it was dried at 90 °C for min−1 for a mechanical evaluation. Te capacitance of 1 h. For the bare PDMS foam, the copper foam was then the pressure sensors was measured using an LCR meter immersed into the PDMS precursor mixture for 1 h and (Hioki-3536, Hioki, Japan) at 200 kHz with 1 V of bias. cured at 90 °C for 3 h. Finally, the sacrifcial copper foam A universal testing machine (JSV-H1000, Japan) was used template was removed by a wet etching method. Te to apply the pressure and a load cell (HF-1, maximum PDMS-coated copper foam was then positioned such load 10 N, load resolution 0.001 N) measured the applied that it foated on the solutions of acetic acid, hydrogen pressure values. All sensor evaluations were conducted peroxide, and deionized (DI) water at a ratio of 1:1:5 for by connecting the LCR meter to a computer for real-time 12 h to etch away the copper foam. After completely measurements. etching the copper, the PDMS foam was soaked in deion- ized (DI) water for 6 h to remove the acid residue. Sub- Results and discussion sequently, the PDMS foam samples were dried at room To confrm the efect of the diluent on the porosity of the temperature. Te fabrication process fnished with the PDMS foam structure, FE-SEM was utilized on various formation of the top and bottom electrodes. Polyethylene locations of the samples. Te porosity of the fabricated terephthalate (PET) flms (Fine chemical Industry, Korea) PDMS foams is calculated from the density of the PDMS attachable with double-sided bonding copper conduc- foam (ρ foam ) and the bulk PDMS density (ρ bulk ) using tive tape (DTS-272, Ducksunghitech Corp., Korea) were Eq.
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]
  • (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).
    [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]
  • 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]