Benzonitrile-based AIE polymer host with simple synthesis process for high-efficiency solution-processable green and blue TADF organic light emitting diodes

Polymer host material have great potential for enable small molecular thermally activated delayed fluorescence (TADF) emitters to construct solution-processed organic light-emitting diodes (OLEDs). Herein, four novel benzonitrile-based polymer host, P4CzCN-PA,...

A supramolecular polymeric heterojunction composed of an all-carbon conjugated polymer and fullerenes

Herein, we design and synthesize a novel all-carbon supramolecular polymer host (SPh) containing conjugated macrocycles interconnected by a linear poly(para-phenylene) backbone.

Effect of hydrogen-bond strength on photoresponsive properties of polymer-azobenzene complexes

Supramolecular complexation between photoresponsive azobenzene chromophores and a photopassive polymer host offers synthetic and design advantages compared with conventional covalent azo-containing polymers. In this context, it is important to understand the impact of the strength of the supramolecular interaction on the optical response. Herein, we study the effect of hydrogen-bonding strength between a photopassive polymer host [poly(4-vinylpyridine), or P4VP] and three azobenzene analogues capable of forming weaker (hydroxyl), stronger (carboxylic acid), or no H-bonding with P4VP. The hydroxyl-functionalized azo forms complete H-bonding complexation up to equimolar ratio with VP, whereas the COOH-functionalized azo reaches only up to 30% H-bond complexation due to competing acid dimerization that leads to partial phase separation and azo crystallization. We show that the stronger azo-polymer H-bonding nevertheless provides higher photoinduced orientation and better performance during optical surface patterning, in terms of grating depth and diffraction efficiency, when phase separation is either avoided altogether or is limited by using relatively low azo contents. These results demonstrate the importance of the H-bonding strength on the photoresponse of azopolymer complexes, as well as the need to consider the interplay between different intermolecular interactions that can affect complexation.

Materials for Electromagnetic Purpose: The Case of a Microstrip Patch Antenna Characteristics Improvement by Additions of Metals as Spherical Inclusions Into the Substrate

This paper deals with the design of metamaterial (MTM) substrates to be used in electromagnetic devices. In particular, the approach has been considered for different investigations having the scope the realization of antennas on flexible substrates. The importance of the topic resides in the potential of conforming the antenna to/on desirable shapes. Flexibility is well exploitable either in advanced communication systems or in biomedical applications, just to mention some. The proposed MTM is made of metallic spherical inclusions of AISI52100, which are embedded in a polymer host. The paper aims to assess the feasibility of increasing the performance of a microstrip patch antenna, and to decrease its size by using the MTM substrate, which is able to locally control the permittivity of the substrate and to create electromagnetic band-gap regions outside of the patch.