Aerogels are considered ideal candidates for various applications, because of their low bulk density, highly porous nature, and functional performance. However, the time intensive nature of the complex fabrication process limits their potential application in various fields. Recently, incorporation of a fibrous network has resulted in production of aerogels with improved properties and functionalities. A facile approach is presented to fabricate hybrid sol–gel electrospun silica‐cellulose diacetate (CDA)‐based nanofibers to generate thermally and mechanically stable nanofiber aerogels. Thermal treatment results in gluing the silica‐CDA network strongly together thereby enhancing aerogel mechanical stability and hydrophobicity without compromising their highly porous nature (>98%) and low bulk density (≈10 mg cm−3). X‐ray photoelectron spectroscopy and in situ Fourier‐transform infrared studies demonstrate the development of strong bonds between silica and the CDA network, which result in the fabrication of cross‐linked structure responsible for their mechanical and thermal robustness and enhanced affinity for oils. Superhydrophobic nature and high oleophilicity of the hybrid aerogels enable them to be ideal candidates for oil spill cleaning, while their flame retardancy and low thermal conductivity can be explored in various applications requiring stability at high temperatures.
Polymersomes have gained a lot of attention in recent years. Their compartmentalized, hollow nature, stability and ability to transport both hydrophilic and hydrophobic cargo has made them attractive for increasingly complex applications in various fields of biomedicine, catalysis and diagnostics. Progress in these fields would therefore benefit from improvements in polymersome functionality. Recently, morphological control of polymersomes, namely the fabrication of various non‐spherical morphologies, has emerged as a means to enhance the usefulness of the polymersomes. In the present review, we highlight the most topical trends in this field and how these developments and the newly acquired knowledge about their nature can be leveraged towards applications. © 2021 Society of Chemical Industry
more » « less- Award ID(s):
- 1945092
- NSF-PAR ID:
- 10451079
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Polymer International
- Volume:
- 70
- Issue:
- 7
- ISSN:
- 0959-8103
- Page Range / eLocation ID:
- p. 951-957
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
null (Ed.)Recent developments in the field of polymer vesicles, i.e. polymersomes, have demonstrated that disrupting the equilibrium conditions of the milieu could lead to shape transformation into stable non-spherical morphologies, bringing on-demand shape control to reality and bearing great promise for cell mimicry and a variety of biomedical applications. Here, we studied the self-assembly behavior of glassy amphiphilic triblock copolymers, poly(ethylene glycol)- block -polystyrene- stat -poly(coumarin methacrylate)- block -poly(ethylene glycol) (PEG- b -P(S- stat -CMA)- b -PEG), and their response to various stimuli. By changing the respective molecular weights of both the hydrophobic P(S- stat -CMA) and the hydrophilic PEG blocks, we varied the hydrophobic volume fraction thereby accessing a range of morphologies from spherical and worm-like micelles, as well as polymersomes. For the latter, we observed that slow osmotic pressure changes induced by dialysis led to a decrease in size while rapid osmotic pressure changes by addition of a PEG fusogen led to morphological transformations into rod-like and tubular polymersomes. We also found out that chemically crosslinking the vesicles before inducing osmotic pressure changes led to the vesicles exhibiting hypotonic shock, atypical for glassy polymersomes. We believe that this approach combining the robustness of triblock copolymers and light-based transformations will help expand the toolbox to design ever more complex biomimetic constructs.more » « less
-
more » « less
Abstract Structured light has revolutionized optical particle manipulation, nano-scaled material processing, and high-resolution imaging. In particular, propagation-invariant light fields such as Bessel, Airy, or Mathieu beams show high robustness and have a self-healing nature. To generalize such beneficial features, these light fields can be understood in terms of caustics. However, only simple caustics have found applications in material processing, optical trapping, or cell microscopy. Thus, these technologies would greatly benefit from methods to engineer arbitrary intensity shapes well beyond the standard families of caustics. We introduce a general approach to arbitrarily shape propagation-invariant beams by smart beam design based on caustics. We develop two complementary methods, and demonstrate various propagation-invariant beams experimentally, ranging from simple geometric shapes to complex image configurations such as words. Our approach generalizes caustic light from the currently known small subset to a complete set of tailored propagation-invariant caustics with intensities concentrated around any desired curve.
-
more » « less
Abstract Liquid crystals (LCs) are omnipresent in living matter, whose chirality is an elegant and distinct feature in certain plant tissues, the cuticles of crabs, beetles, arthropods, and beyond. Taking inspiration from nature, researchers have recently devoted extensive efforts toward developing chiral liquid crystalline materials with self‐organized nanostructures and exploring their potential applications in diverse fields ranging from dynamic photonics to energy and safety issues. In this review, an account on the state of the art of emerging chiral liquid crystalline nanostructured materials and their technological applications is provided. First, an overview on the significance of chiral liquid crystalline architectures in various living systems is given. Then, the recent significant progress in different chiral liquid crystalline systems including thermotropic LCs (cholesteric LCs, cubic blue phases, achiral bent‐core LCs, etc.) and lyotropic LCs (DNA LCs, nanocellulose LCs, and graphene oxide LCs) is showcased. The review concludes with a perspective on the future scope, opportunities, and challenges in these truly advanced functional soft materials and their promising applications.
-
more » « less
Abstract The rapid advancement of functional data in various application fields has increased the demand for advanced statistical approaches that can incorporate complex structures and nonlinear associations. In this article, we propose a novel functional random forests (FunFor) approach to model the functional data response that is densely and regularly measured, as an extension of the landmark work of Breiman, who introduced traditional random forests for a univariate response. The FunFor approach is able to predict curve responses for new observations and selects important variables from a large set of scalar predictors. The FunFor approach inherits the efficiency of the traditional random forest approach in detecting complex relationships, including nonlinear and high-order interactions. Additionally, it is a non-parametric approach without the imposition of parametric and distributional assumptions. Eight simulation settings and one real-data analysis consistently demonstrate the excellent performance of the FunFor approach in various scenarios. In particular, FunFor successfully ranks the true predictors as the most important variables, while achieving the most robust variable sections and the smallest prediction errors when comparing it with three other relevant approaches. Although motivated by a biological leaf shape data analysis, the proposed FunFor approach has great potential to be widely applied in various fields due to its minimal requirement on tuning parameters and its distribution-free and model-free nature. An R package named ’FunFor’, implementing the FunFor approach, is available at GitHub.
