Stimulus Responsive Nanoparticles

Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes

Responsive polymer photonics

Stimulus-responsive materials: This thesis describes the development of stimulus-responsive polymeric materials based on liquid crystalline polymers and hydrogels. Novel responsive molecular building blocks were designed and synthesised. Specific monomer mixtures were crosslinked by UV-photopolymerisation methods, and the response of the obtained (structured) material was analysed

Beads, boats and switches: making things happen with molecular photoswitches

In this paper we present recent results obtained with a stimulus-responsive materials based on the photo-switchable behaviour exhibited by spiro-cyclic derivatives. Our results suggest that these highly novel materials offer unique capabilities hitherto inaccessible using conventional materials. In particular, we will focus on photocontrolled guest binding and release, inherent signalling of status, photo-actuation and solvent driven motion of small structures as examples of the fascinating behaviour of these exceptional materials

Smart Drug Delivery Strategies Based on Porous Nanostructure Materials

The control of drug delivery can have a great effect on its efficacy. An optimum concentration range of drugs can play a significant role in the human body, and it can cause harm to humans when it exceeds the range of the drug concentration. Recently, a variety of drug deliveries and their targeted systems have been studied to minimize drug loss and maximize the amount of drug accumulated in the required area, thus increasing drug bioavailability. In addition, we should especially consider the prevention of its harmful side-effects in the human body. Innovative drug delivery systems based on biodegradable, natural or synthetic polymers, micro- or nano-particles, lipoproteins, micelles, TiO2 nanotube arrays (TNTs), nanoporous anodic aluminum oxide (AAO), and so on were developed, which combined magnetic targeting and stimulus-responsive in drug delivery systems. The composition of delivery carriers and the stimulus-responsive elements proved stimulus-responsive drug release as a smart drug delivery system

Responsive anionophores with AND logic multi-stimuli activation

Artificial ion transport systems have emerged as an important class of compounds that promise applications in chemotherapeutics as anticancer agents or to treat channelopathies. Stimulus-responsive systems that offer spatiotemporally controlled activity for targeted applications remain rare. Here we utilize dynamic hydrogen bonding interactions of a 4,6-dihydroxy-isophthalamide core to generate a modular platform enabling access to stimuli-responsive ion transporters that can be activated in response to a wide variety of external stimuli, including light, redox, and enzymes, with excellent OFF-ON activation profiles. Alkylation of the two free hydroxyl groups with stimulus-responsive moieties locks the amide bonds through intramolecular hydrogen bonding and hence makes them unavailable for anion binding and transport. Triggering using a particular stimulus to cleave both cages reverses the hydrogen bonding arrangement, to generate a highly preorganized anion binding cavity for efficient transmembrane transport. Integration of two cages that are responsive to orthogonal stimuli enables multi-stimuli activation, where both stimuli are required to trigger transport in an AND logic process. Importantly, the strategy provides a facile method to post-functionalize the highly active transporter core with a variety of stimulus-responsive moieties for targeted activation with multiple triggers

New approaches in the engineering and characterization of macromolecular interfaces across the length scales: applications to hydrophobic and stimulus responsive polymers

The aim of the present Thesis is to enhance characterization and surface engineering approaches to test and control physico-chemical changes on modified hydrophobic (LDPE and PDMS) and stimulus-responsive (PFS) polymers across different length scales. [Here LDPE denotes low density polyethylene, PDMS stands for poly(dimethylsiloxane), and PFS for poly (ferrocenyldimethylsilanes)]. Efforts have been made to design and engineer desired surface properties of selected polymers and to characterize the chemical composition, electrokinetic and mechanical properties by various experimental techniques from the nano to the meso scale. Furthermore, a comparison of these techniques has been carried out in order to understand the aforementioned issues

Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer

We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.We are thankful for support from MICINN (MAT2013-46753-C2-1-P, MAT2013-46502-C2-1/2-P and CTQ2011-26507), Eusko Jaurlaritza (S-PE13UN016) and Generalitat Valenciana PrometeoII/2014/076

Tunable Photonic Multilayers from Stimulus-Responsive, Photo-Crosslinkable Polymers

This dissertation describes the synthesis of photo-crosslinkable copolymers and their utilization for the fabrication and testing of tunable and responsive one-dimensional (1D) photonic multilayers. Photonic multilayers exhibit structural color due to the interference of incident light at layer interfaces, providing a convenient route towards optically responsive materials that do not rely on potentially light- or oxygen-sensitive chromophore-containing pigments and dyes. A fabrication technique based on sequential spin-coating and crosslinking of photo-crosslinkable polymers is used to assemble tunable and responsive photonic multilayers. Chapter One introduces the fundamental underlying principles of 1D photonic structures and explores their importance in a variety of areas, including sensors, responsive films, as well as the necessity of their optimization through routes such as the incorporation of nanocomposites for enhanced refractive index. This chapter also details the experimental approach used here for fabricating tunable and responsive 1D photonic multilayers utilizing sequential spin-coating and crosslinking of photo-crosslinkable polymers. Chapter Two describes the use of these multilayer photonic films as thermochromic materials using poly(N-isopropylacrylamide) (PNIPAM) as the low-refractive index, stimulus responsive layers and poly(p-methyl styrene) (PpMS) as the high-refractive index, hydrophobic layers. Temperature is utilized as an analyte to validate this platform as a feasible and flexible approach for the fabrication of a variety of tunable and responsive structures. Building upon the knowledge developed in Chapters 1 and 2, this photonic sensing platform is next expanded to detect additional analytes and further optimize sensor performance by improving reflectance efficiency, response and exploring various multilayer geometries and arrays. Chapter 3 describes the utilization of polymeric photonic multilayers for colorimetric sensing of ionizing radiation. Chapter 4 explores a method of enhancing the reflectance efficiency of multilayers through the incorporation of high refractive index zirconia nanoparticles. The utilization of nanoparticles also enables the fabrication of all-gel multilayers for flexible, potentially mechanochromatic, photonic materials by eliminating the necessity of the high refractive index, but brittle, PpMS. Chapter 5 explores in detail the kinetic response of photonic multilayers with a variety of responsive polymer materials during the swelling and de-swelling phases. Chapter 6 details how this approach can be expanded to create new multilayer geometries, including Bragg filters, as well as multifunctional sensors and arrays on a single substrate. Chapter 7 introduces preliminary work studying the electrochromic response of photonic multilayers. Applied voltage triggers the reversible de-swelling of the responsive layers and subsequently a blue-shift in the wavelength of reflected light. Finally, Chapter 8 provides a summary of this dissertation and proposes future directions for photonic polymer multilayers