For polymer-blend films, local dynamics
in confined polymer domains tend to differ from the bulk because of
significant contributions from the polymer–polymer interface.
Herein, we investigated the diffusion dynamics of entangled polymer
thin films confined between different polymers in a direction perpendicular
to the surface using neutron reflectivity. We found that a bilayer
of poly(methyl methacrylate) (PMMA) and deuterated PMMA (dPMMA) sandwiched between polystyrene (PS) layers exhibited significant
increase in mobility near the polymer–polymer interface with
decreasing PMMA thickness. This indicates that the contribution of
repulsive interactions at the immiscible polymer–polymer interface
becomes more significant as the film thickness decreases. We also
found that the interfacial roughness between PMMA and PS (28 Å
at equilibrium) and soft confinement of PS layers did not significantly
affect the change in the diffusion dynamics of the adjacent PMMA.
This was evidenced by comparison with the diffusion results of multilayers
with a flat interface (8 Å at equilibrium) between PMMA and hard
PS by UV cross-linking.
For
graphene-based composites, the dynamics of polymers confined
between graphene sheets are a key parameter governing the overall
mechanical properties of bulk materials. Here, we used neutron reflectivity
(NR) to measure the diffusion dynamics of polymer melts confined between
graphene oxide (GO) surfaces. From the NR results, we found that the
diffusion coefficients of poly(methyl methacrylate) (PMMA) between
the GO sheets were dramatically reduced by more than 1 order of magnitude
when the film thickness was less than ∼3 times the gyration
radius of the bulk polymer (R
g), whereas
the diffusion of the polystyrene (PS) films sandwiched between GO
sheets was only three times slower as the PS thickness decreased from
∼8 R
g to 1 R
g. This difference was due to the fact that the polymer-GO
interaction significantly influences the dynamics of confined polymer
melts.
Co-development of healthcare technology with users helps produce user-friendly products, ensuring safe device usage and meeting patients’ needs. For developers considering healthcare innovations, engaging user experience can reduce production time and cost while maximizing device application. The purpose of this paper is to report lessons learned from the development of a 3D printed origami ventilator prototype in response to the rise of ventilator demand due to the Coronavirus disease (COVID-19) pandemic. We conducted focus groups with frontline clinicians working in an Intensive Care Unit of a large urban hospital in Vancouver, British Columbia, Canada. In the interdisciplinary focus groups, we identified challenges, practical tips about product development, the human needs of technology, and cross-discipline peer learning. The focus group discussions provide useful insight into the technology development for complex clinical contexts. Based on our experiences, we articulate five practical tips for co-development of healthcare technology - AGILE: Analyse users’ needs first, Gain insights into complex context, Involve users early and frequently, Lead with a prototype, and Educate and support. Through sharing the tips and lessons learned, we wish to emphasize the necessity of meaningful multi-disciplinary collaboration during healthcare technology development and promote the inclusion of frontline clinicians during these initiatives.
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