Patterning micron-sized features in a cross-linked poly(acrylic acid) film by a wet etching process

Winkleman, Adam; Perez‐Castillejos, Raquel; Lahav, Michal; Narovlyansky, Max; Rodriguez, Leonard; Whitesides, George M.

doi:10.1039/b611630b

Cited by 22 publications

(17 citation statements)

References 36 publications

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“…Among these, polyvinyl alcohol, polyacrylic acid, chitosan, silk, starch, cellulose derivatives, and algae‐ and yeast‐derived polysaccharides are common options. [ 18–23 ] Due to its excellent film‐forming capabilities, fast dissolution rate, and biodegradable nature, we selected pullulan, a fungal‐derived polysaccharide, for the present carrier‐replica swimmer system (Table 1). [ 24,25 ] Pullulan is commonly found in the food industry as a biodegradable adhesive, binder, and the main ingredient of rapidly dissolving strips for fresh breath.…”

Section: Resultsmentioning

confidence: 99%

Small‐Scale Propellers Deliver Miniature Versions of Themselves

Karshalev

Yan

Campos

et al. 2020

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propelling Mg-based micromotor toward extended retention in the gastrointestinal tract of mice. [12] Finally, Kong et al. have developed a small-scale tube, propelled by the Marangoni effect, which by virtue of its motion mechanism, releases titanium oxide-based micromotors. [13] Subsequently, the sample chamber was irradiated with UV light which served for both powering the micromotors for active propulsion and initiating their organic pollutant degradation reaction.Inspired by fascinating examples from the animal kingdom, we present a selfpropelled carrier, capable of autonomous motion through its environment while dynamically delivering a large number of autonomously miniature replica propellers (MRPs) at preselected times. The propeller and their released MRPs move autonomously by catalytic decomposition of H 2 O 2 by active platinum (Pt) at their tail section. [14,15] Each carrier holds a set number of MRPs which it delivers "on-the-fly" at predetermined times by means of a transient sacrificial layer that dissolves during its propulsion in the solution. The released MRPs display an immediate motion capability and move freely and independently. Such use of sacrificial layers offers autonomous delivery ability without external intervention. Careful control and selection of the transient materials allows tuning of the release behavior and programmable delivery. A range of transient materials, summarized in Table 1, has been investigated here for fabricating the delivered propellers. Among these, the combination of sugar and pullulan can be readily formulated to provide an attractive controlled dissolution in the surrounding aqueous environments. The majority of our initial delivery studies were thus performed with the sugar-pullulan system. Subsequently, to illustrate controllable and delayed pH-responsive release of replicas, we utilized pH-responsive methacrylic acid-based polymers (Eudragit). Additionally, the delivery time window has been tailored by tuning the thickness of the transient layer. The influence of the delivery process upon the propelling behavior of the carriers and of the self-propelled copies has been examined. By judicious control of the sacrificial materials, stimuli-responsive behavior is established with pH as a common stimulus, to allow considerable extension of the delivery period from minutes to days. Finally, we demonstrate multi-generation propelling systems, capable of delivering a large amount of autonomous MRPs, segregated generations, and at different predetermined times. Such programmable delivery of the multiple generations of independent propellers relies on the coupling of transient Small-scale actuators and propellers have benefited from advances in materials and manufacturing to become more lifelike. Inspired by animal species, multi-generational chemically powered artificial propellers that carry small versions of themselves and deliver them "on-the-fly" are described. The released replicas are capable of autonomous propulsion and propelling immediately after detachment....

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Section: Resultsmentioning

confidence: 99%

Small‐Scale Propellers Deliver Miniature Versions of Themselves

Karshalev

Yan

Campos

et al. 2020

Small

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“…An essential step in advancing the development to fully utilize the superior properties of PAA ionic hydrogels in sensors is rapid prototyping using fast patterning technique to make fine and complicated microstructures. There have been demonstrations of several techniques to pattern PAA ionic hydrogels, including microcontact printing,[2f,4] ion beam lithography,[2e,i,5] micromolding,[2h,6] evaporation‐induced self‐assembly, wet etching, and photomask‐based lithography. [2c,9] However, most of these techniques are time‐consuming or require fastidious processing condition.…”

Section: Methodsmentioning

confidence: 99%

Rapid 3D Patterning of Poly(acrylic acid) Ionic Hydrogel for Miniature pH Sensors

et al. 2015

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“…Detailed study of influence of different metal cations on crosslinking PAA films is presented in paper [16]. Table 1 lists these cations-and those that failed to cross-link the film-by atomic number.…”

Section: Films Based On Cross-linked Carboxyl-containing Polymersmentioning

confidence: 99%

“…More details regarding such an interaction Table 1. Metal salts that cross-link a film of PAA and that fail to do so a) [16].…”

Section: Films Based On Cross-linked Carboxyl-containing Polymersmentioning

confidence: 99%

Polymer Coatings for Protection of Wood and Wood-Based Materials

Сахно¹,

Barashkov²,

Irgibaeva³

et al. 2016

ACES

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Three major types of protective coating of wood and wood-based materials have been considered. These three types include the coatings based on carboxyl-containing water-soluble polymers which are easily cross-linked by inorganic salts or OH-containing compounds, pH-sensitive coatings and polymer multi-layer structures. First of three mentioned approaches allows affecting permeability and enhancing the prevention the loss of water from the surface of wood to its surrounding. The advantage of the second approach is its ability to vary and purposely adjust the polymer composition and the number and distribution of -COOH groups in the chain which make the originally water-soluble polymers completely insoluble. The strong feature of the third approach which includes broad use of hydrogen-bonded films produced by layer-by-layer self-assembly is the possibility of manipulation of coatings stability after construction.

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Patterning micron-sized features in a cross-linked poly(acrylic acid) film by a wet etching process

Cited by 22 publications

References 36 publications

Small‐Scale Propellers Deliver Miniature Versions of Themselves

Small‐Scale Propellers Deliver Miniature Versions of Themselves

Rapid 3D Patterning of Poly(acrylic acid) Ionic Hydrogel for Miniature pH Sensors

Polymer Coatings for Protection of Wood and Wood-Based Materials

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