Production technology and applications of honeycomb films

Biopolymer Honeycomb Microstructures: A Review

In this review, we present a comprehensive summary of the formation of honeycomb microstructures and their applications, which include tissue engineering, antibacterial materials, replication processes or sensors. The history of the honeycomb pattern, the first experiments, which mostly involved the breath figure procedure and the improved phase separation, the most recent approach to honeycomb pattern formation, are described in detail. Subsequent surface modifications of the pattern, which involve physical and chemical modifications and further enhancement of the surface properties, are also introduced. Different aspects influencing the polymer formation, such as the substrate influence, a particular polymer or solvent, which may significantly contribute to pattern formation, and thus influence the target structural properties, are also discussed.

Fabrication of Adsorption-Type Hierarchical Functional Films by Using a Facile Swollen Based Breath Figure Method

The morphology transition from primary to hierarchical adsorption-type microporous domains of amphiphilic block copolymer (BCP) honeycomb-structured films is demonstrated by a facile swollen based breath figure (BF) method. The characteristic parameters of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) hierarchical micro- and submicro-porous films can be controlled by changing the length of segments or subsequent swelling conditions. A plausible mechanism is demonstrated in this research. A typical amphiphilic BCP with very low volume content of hydrophilic blocks (f_P4VP ≤ 0.050) can efficiently stabilize water droplets and inherently assist in the formation of morphology transition. This BCP film can be used for Cr(VI) removal from wastewater, which additionally has enormous potential application in the field of novel optical devices, soft lithography, size-selective separation, etc. This article is protected by copyright. All rights reserved.

Crystalline lamellar films with honeycomb structure from comb-like polymers of poly(2-long-alkyl-2-oxazoline)s

Comb-like copolymers are usually structured by grafting polymeric side chains onto main polymer chain. There are few reports of comb-on-comb polymers in which dense secondary side chains are grafted onto primary side chain. In this work, we synthesized comb polymers with grafted-on-graft side chains (c-PEI-g-Acyl) via an effective acylation reaction of comb polymers possessing polyethyleneimine (PEI) side chain with long-alkyl acyl chlorides. For comparison, we also synthesized homopolymers l-PEI-g-Acyls via reaction of linear PEI with long-alkyl acyl chlorides. Then, we investigated their crystalline feature in the film formation by XRD, DSC and SEM, and found that the polymers tend to form hexagonal lamella structures with bilayer alkyl spacing. The comb polymers c-PEI-g-Acyls and linear polymers l-PEI-g-Acyls were used in preparation of honeycomb film by the "breath-figure" process by dropping chloroform solution of the polymers on substrate. Different to many honeycomb polymeric films which are supported by amorphous phase, interestingly, our polymers easily afford honeycomb films which are supported by crystalline lamellae frames under higher humidity condition. It was found that the comb polymers of c-PEI-g-Acyls with longer PEI primary side chain and long alkyl secondary side chain have advantages in producing honeycomb film than linear polymers of l-PEI-g-Acys.