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McKenzie TJ, Brunet T, Kissell LN, Strobbia P, Ayres N. Polydimethylsiloxane Polymerized Emulsions for Acoustic Materials Prepared Using Reactive Triblock Copolymer Surfactants. ACS Appl Mater Interfaces 2023; 15:58917-58930. [PMID: 38063480 DOI: 10.1021/acsami.3c14859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Porous polymers have interesting acoustic properties including wave dampening and acoustic impedance matching and may be used in numerous acoustic applications, e.g., waveguiding or acoustic cloaking. These materials can be prepared by the inclusion of gas-filled voids, or pores, within an elastic polymer network; therefore, porous polymers that have controlled porosity values and a wide range of possible mechanical properties are needed, as these are key factors that impact the sound-dampening properties. Here, the synthesis of acoustic materials with varying porosities and mechanical properties that could be controlled independent of the pore morphology using emulsion-templated polymerizations is described. Polydimethylsiloxane-based ABA triblock copolymer surfactants were prepared using reversible addition-fragmentation chain transfer polymerizations to control the emulsion template and act as an additional cross-linker in the polymerization. Acoustic materials prepared with reactive surfactants possessed a storage modulus of ∼300 kPa at a total porosity of 71% compared to materials prepared using analogous nonreactive surfactants that possessed storage modulus values of ∼150 kPa at similar porosities. These materials display very low longitudinal sound speeds of ∼35 m/s at ultrasonic frequencies, making them excellent candidates in the preparation of acoustic devices such as metasurfaces or lenses.
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Affiliation(s)
- Tucker J McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Thomas Brunet
- Institut de Mécanique et d'Ingénierie, University of Bordeaux─CNRS─Bordeaux INP, Talence 33405, France
| | - Lyndsay N Kissell
- Department of Chemistry, University of Cincinnati, 201 Crosley Tower, 301 Clifton Ct, Cincinnati, Ohio 45221, United States
| | - Pietro Strobbia
- Department of Chemistry, University of Cincinnati, 201 Crosley Tower, 301 Clifton Ct, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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McKenzie TJ, Cawood C, Davis C, Ayres N. Synthesis of patterned polyHIPE-hydrogel composite materials using thiol-ene chemistry. J Colloid Interface Sci 2023; 645:502-512. [PMID: 37159992 DOI: 10.1016/j.jcis.2023.04.132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/11/2023]
Abstract
Elastomeric materials combining multiple properties within a single composite are highly desired in applications including biomaterials interfaces, actuators, and soft robotics. High spatial resolution is required to impart different properties across the composite for the intended application, but many techniques used to prepare these composites rely on multistep and complex methods. There is a need for the development of simple and efficient platforms to design layered composite materials. Here, we report the synthesis of horizontally- and vertically-patterned composites consisting of PDMS-based polymerized high internal phase emulsion (polyHIPE) porous elastomers and PDMS/PEG hydrogels. Composites with defined interfaces that were mechanically robust were prepared, and rheological analysis of the polyHIPE and hydrogel layers showed storage moduli values of ∼ 35 kPa and 45 kPa respectively. The compressive Young's Modulus and maximum strain of the polyHIPEs were dependent on the thiol to ene ratio in the formulation and obtained values ranging from 6 to 25 kPa and 50-65% respectively. The mechanical properties, total porosity of the polyHIPE, and swelling ratio of the hydrogel were unaffected by the patterning technique compared to non-patterned controls. PolyHIPE-hydrogel composite materials having up to 7-different horizontally pattered layers could be prepared that could expand and contract up hydration and drying.
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Affiliation(s)
- Tucker J McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Christian Cawood
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Chelsea Davis
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States.
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Ruhunage CK, Dhawan V, McKenzie TJ, Hoque A, Rahm CE, Nawarathne CP, Ayres N, Cui XT, Alvarez NT. Hydrophilic Micro- and Macroelectrodes with Antibiofouling Properties for Biomedical Applications. ACS Biomater Sci Eng 2022; 8:2920-2931. [PMID: 35710337 PMCID: PMC10080669 DOI: 10.1021/acsbiomaterials.2c00173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Implantable neural electrodes are generally used to record the electrical activity of neurons and to stimulate neurons in the nervous system. Biofouling triggered by inflammatory responses can dramatically affect the performance of neural electrodes, resulting in decreased signal sensitivity and consistency over time. Thus, long-term clinical applications require electrically conducting electrode materials with reduced dimensions, high flexibility, and antibiofouling properties that can reduce the degree of inflammatory reactions and increase the lifetime of neural electrodes. Carbon nanotubes (CNTs) are well known to form flexible assemblies such as CNT fibers. Herein, we report the covalent functionalization of predefined CNT fiber and film surfaces with hydrophilic, antibiofouling phosphorylcholine (PC) molecules. The electrochemical and spectroscopic characteristics, impedance properties, hydrophilicity, and in vitro antifouling nature of the functionalized CNT surfaces were evaluated. The hydrophilicity of the functionalized CNT films was demonstrated by a decrease in the static contact angle from 134.4° ± 3.9° before to 15.7° ± 1.5° after one and fully wetting after three functionalization cycles, respectively. In addition, the extent of protein absorption on the functionalized CNT films was significantly lower than that on the nonfunctionalized CNT film. Surprisingly, the faradic charge-transfer properties and impedance of the CNT assemblies were preserved after functionalization with PC molecules. These functionalized CNT assemblies are promising for the development of low-impedance neural electrodes with higher hydrophilicity and protein-fouling resistance to inhibit inflammatory responses.
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Affiliation(s)
- Chethani K Ruhunage
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Tucker J McKenzie
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Abdul Hoque
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Connor E Rahm
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Chaminda P Nawarathne
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Noe T Alvarez
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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McKenzie TJ, Smail S, Rost K, Rishi K, Beaucage G, Ayres N. Multi-layered polymerized high internal phase emulsions with controllable porosity and strong interfaces. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.124116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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McKenzie TJ, Heaton PS, Rishi K, Kumar R, Brunet T, Beaucage G, Mondain-Monval O, Ayres N. Storage Moduli and Porosity of Soft PDMS PolyMIPEs Can Be Controlled Independently Using Thiol–Ene Click Chemistry. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00217] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tucker J. McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Paul S. Heaton
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Kabir Rishi
- Department of Chemical and Materials Engineering, The University of Cincinnati, Cincinnati, Ohio 45242-0012, United States
| | - Raj Kumar
- University of Bordeaux—CNRS, Centre de Recherche Paul Pascal, Pessac 33600, France
| | - Thomas Brunet
- Institut de Mécanique et d’Ingénierie, University of Bordeaux—CNRS—Bordeaux INP, Talence 33402, France
| | - Gregory Beaucage
- Department of Chemical and Materials Engineering, The University of Cincinnati, Cincinnati, Ohio 45242-0012, United States
| | | | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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Affiliation(s)
- Emily Dalton
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Qinyuan Chai
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Molly W. Shaw
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center Cincinnati Ohio 45229
| | - Tucker J. McKenzie
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Eric S. Mullins
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center Cincinnati Ohio 45229
| | - Neil Ayres
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
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Simons-Morton BG, McKenzie TJ, Stone E, Mitchell P, Osganian V, Strikmiller PK, Ehlinger S, Cribb P, Nader PR. Physical activity in a multiethnic population of third graders in four states. Am J Public Health 1997; 87:45-50. [PMID: 9065225 PMCID: PMC1380763 DOI: 10.2105/ajph.87.1.45] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES This research assessed the amount of daily physical activity in a multiethnic sample of US third-grade students. METHODS Physical activity interviews were conducted with 2410 third graders from 96 schools in four states. Blood pressure, cholesterol, body mass index, timed run for distance, physical-activity self-efficacy, and perceived support for physical activity were also assessed. RESULTS Students reported a daily average of 89.9 minutes of moderate to vigorous physical activity, 34.7 minutes of vigorous activity, and 120.4 minutes of sedentary behavior; however, 36.6% obtained less than 60 minutes of moderate to vigorous physical activity daily, and 12.8% reported less than 30 minutes. Boys reported more physical and sedentary activity than girls; White children reported more activity than Black or Hispanic children; California children reported the most activity and Louisiana children the least. Geographic location, male gender, lower cholesterol, higher perceived efficacy in physical activity, and higher social support were associated with more physical activity. CONCLUSIONS Average reported activity met the Year 2000 objectives; however, many students reported less than recommended amounts of activity. These findings support the need for health promotion programs that increase the number of physically active children.
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Affiliation(s)
- B G Simons-Morton
- National Institute of Child health and Human Development, Rockville, MD 20852, USA
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