The human cost of the COVID-19 pandemic has taken a great toll, and led, around the globe, to a shortage in personal protective equipment (PPE) such as medical exam gloves. To face this shortage and keep themselves and patients safe, many front-line healthcare providers have been overextending the life of PPE. Though not ideal, one pragmatic solution often used is the practice of sanitization and extended use of existing PPE. The data produced by these experiments should help determine an acceptable reusability window of PPE in a working environment, by which the effective use time may be extended and justified. The effect of repeated sanitization, using soap and water, on the mechanical performance was investigated for latex and nitrile elastomeric medical exam gloves. Tensile tests were performed for various manufacturer brands commonly used in the United States (Glovepak Europa, Polymed and Sempersure) and India (Surgiglove). Tensile test samples were prepared for each studied glove and treatment combination. Nitrile gloves were observed to be more uniformly affected by the application of soap and water sanitization than latex gloves. Glovepak Europa nitrile gloves saw significant changes (p≤0.001) in elastic modulus after 5, 10 and 20 treatments losing 31.5%, 42.7% and 49.7%, respectively.more »
Survival of polymeric microstructures subjected to interrogatory touch
Polymeric arrays of microrelief structures have a range of potential applications. For example, to influence wettability, to act as biologically inspired adhesives, to resist biofouling, and to play a role in the “feel” of an object during tactile interaction. Here, we investigate the damage to micropillar arrays comprising pillars of different modulus, spacing, diameter, and aspect ratio due to the sliding of a silicone cast of a human finger. The goal is to determine the effect of these parameters on the types of damage observed, including adhesive failure and ploughing of material from the finger onto the array. Our experiments point to four principal conclusions [1]. Aspect ratio is the dominant parameter in determining survivability through its effect on the bending stiffness of micropillars [2]. All else equal, micropillars with larger diameter are less susceptible to breakage and collapse [3]. The spacing of pillars in the array largely determines which type of adhesive failure occurs in non-surviving arrays [4]. Elastic modulus plays an important role in survivability. Clear evidence of elastic recovery was seen in the more flexible polymer and this recovery led to more instances of pristine survivability where the stiffer polymer tended to ablate PDMS. We developed a more »
- Editors:
- Kim, Tae-il
- Award ID(s):
- 1929748
- Publication Date:
- NSF-PAR ID:
- 10358134
- Journal Name:
- PLOS ONE
- Volume:
- 16
- Issue:
- 9
- Page Range or eLocation-ID:
- e0255980
- ISSN:
- 1932-6203
- Sponsoring Org:
- National Science Foundation
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Metal-mediated cross-coupling reactions offer organic chemists a wide array of stereo- and chemically-selective reactions with broad applications in fine chemical and pharmaceutical synthesis.1 Current batch-based synthesis methods are beginning to be replaced with flow chemistry strategies to take advantage of the improved consistency and process control methods offered by continuous flow systems.2,3 Most cross-coupling chemistries still encounter several issues in flow using homogeneous catalysis, including expensive catalyst recovery and air sensitivity due to the chemical nature of the catalyst ligands.1 To mitigate some of these issues, a ligand-free heterogeneous catalysis reaction was developed using palladium (Pd) loaded into a polymeric network of a silicone elastomer, poly(hydromethylsiloxane) (PHMS), that is not air sensitive and can be used with mild reaction solvents (ethanol and water).4 In this work we present a novel method of producing soft catalytic microparticles using a multiphase flow-focusing microreactor and demonstrate their application for continuous Suzuki-Miyaura cross-coupling reactions. The catalytic microparticles are produced in a coaxial glass capillary-based 3D flow-focusing microreactor. The microreactor consists of two precursors, a cross-linking catalyst in toluene and a mixture of the PHMS polymer and a divinyl cross-linker. The dispersed phase containing the polymer, cross-linker, and cross-linking catalyst is continuously mixed and thenmore »
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A new approach is reported to fabricate micropillar arrays on transparent surfaces by employing the light‐induced self‐writing technique. A periodic array of microscale optical beams is transmitted through a thin film of photo‐crosslinking acrylate resin. Each beam undergoes self‐lensing associated to photopolymerization‐induced changes in the refractive index of the medium, which counters the beam's natural tendency to diverge over space. As a result, a microscale pillar grows along each beam's propagation path. Concurrent, parallel self‐writing of micropillars leads to the prototyping of micropillar‐based arrays, with the capability to precisely vary the pillar diameter and inter‐spacing. The arrays are spray coated with a thin layer of polytetrafluoroethylene (PTFE) nanoparticles to create large‐area superhydrophobic surfaces with water contact angles greater than 150° and low contact angle hysteresis. High transparency is achieved over the entire range of micropillar arrays explored. The arrays are also mechanically durable and robust against abrasion. This is a scalable, straightforward approach toward structure‐tunable micropillar arrays for functional surfaces and anti‐wetting applications.
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Accepted Manuscript1.0
- Publisher's Version of Record
- https://doi.org/10.1371/journal.pone.0255980
