Time-Resolved Surface Rearrangements of Poly(2-hydroxyethyl methacrylate-<i>block</i>-isoprene) in Response to Environmental Changes

Senshu, Kazuhisa; Yamashita, Shuzo; Mori, Hideharu; Ito, Masumi; Hirao, and Akira; Nakahama, Seiichi

doi:10.1021/la980815+

Cited by 66 publications

(54 citation statements)

References 31 publications

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“…This responsive behavior is similar to that exhibited by surfaces modified with grafted amphiphilic block copolymer molecules upon exposure to solvents or temperature. [21][22][23][24][25][26][27][28] Micelles offer additional advantages for surface modification because they are individual nanoscale entities that can be readily coated over a wide range of substrates.…”

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confidence: 99%

Block Copolymer Micelles as Switchable Templates for Nanofabrication

et al. 2006

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Block copolymer inverse micelles from polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP) deposited as monolayer films onto surfaces show responsive behavior and are reversibly switchable between two states of different topography and surface chemistry. The as-coated films are in the form of arrays of nanoscale bumps, which can be transformed into arrays of nanoscale holes by switching through exposure to methanol. The use of these micellar films to act as switchable etch masks for the structuring of the underlying material to form either pillars or holes depending on the switching state is demonstrated.Block copolymers have been explored extensively as templates for nanofabrication. 1-3 Nanostructures form as a result of the microphase separation driven by chemical incompatibility between the constituent blocks of the copolymer. The morphology and dimensions of the nanostructures thus obtained are tunable with the suitable choice and length of the constituent polymer blocks. Nanoscale polymer etch masks were obtained from microphase-separated block copolymer thin films by selective degradation and removal of one of the blocks, whereas the other block serves as a lithographic mask to etch the underlying substrate. [4][5][6][7] Surface micelles that form through the preferred adsorption of one polymer block onto the surface have also been used to structure surfaces, and the as-coated film offers an inherent mass thickness contrast necessary for transferring structures by etching. 8,9 Block copolymers are furthermore well known to form micelles in solution when dissolved in selective solvents. 10,11 The soluble block forms a swollen corona in the solution phase shielding the insoluble block that forms a highly condensed core. These micelles can be spherical, cylindrical, or wormlike depending on the block ratios, the interfacial energy between the blocks, and the solvent quality. There have been several reports on the deposition of spherical micelles on surfaces to obtain arrays of functional centers that were used for making nanoparticle arrays 12-14 and other functional 15 or responsive 14,16 surfaces.Micellar films loaded with metal salts or nanoparticles derived from them have been used as etch masks to structure the underlying substrate. In the remarkable case of PS-b-P2VP micelles loaded with AuCl 4 -, the authors found an inversion of the relative etch rates upon reducing the included salt to gold nanoparticles, allowing the inversion of the etch contrast depending on the redox state of the mask. 17 We report in this letter the responsive behavior of an amphiphilic diblock copolymer micellar array that can be switched between two complementary surface topographies and polarities by simple means as well as its use as an etch mask for the structuring of the underlying silicon substrate. The complementary topographies obtained from the micellar film lead to complementary topographies in the silicon, resulting in either arrays of pillars or holes depending on the switching state of the micellar film (Figures...

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Block Copolymer Micelles as Switchable Templates for Nanofabrication

et al. 2006

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“…The sand in the treated and nontreated pots was saturated with water (via wetting from the base of the pot to simulate field drip irrigation several cm below the polymer) and the weight of the pots was monitored over time to determine soil water evaporation ( Figure 6). Figure 6 shows that soil water evaporation was reduced in the polymer-treated sand, even at a low polymer loading of just 48 g m 22 . For comparison, sprayable biopolymer-derived mulches described previously use significantly higher loadings of the active solids (>300 g m 22 ).…”

Section: Assessment Of Pdms(50)-peg(50) Performance As a Switchable Bmentioning

confidence: 99%

“…Figure 6 shows that soil water evaporation was reduced in the polymer-treated sand, even at a low polymer loading of just 48 g m 22 . For comparison, sprayable biopolymer-derived mulches described previously use significantly higher loadings of the active solids (>300 g m 22 ). [51][52][53][54] The results further show that soil water evaporation from the polymer-treated sand decreased by 76 6 7.7% compared to the control at 20 8C (close to the melting temperature of the polymer), while soil water evaporation decreased by 66 6 6.6% above the melting temperature of the polymer.…”

Section: Assessment Of Pdms(50)-peg(50) Performance As a Switchable Bmentioning

confidence: 99%

“…Further, the time taken for the droplet to penetrate the sand increased at higher loadings of PDMS(50)-PEG(50) (e.g., 7.9 s for a loading of 35.1 g m 22 vs 44.8 s for a loading of 56.6 g m 22 ).…”

Section: Assessment Of Pdms(50)-peg(50) Performance As a Switchable Bmentioning

confidence: 99%

“…17 Of particular interest are a group of environmentally responsive materials whose surfaces can switch between hydrophobic and hydrophilic character in response to the polarity of the medium in contact with the polymer surface. [18][19][20][21][22][23][24][25][26][27] Environmentally responsive polymer systems undergo surface rearrangements in response to the polarity of their surrounding environments to affect changes in their surface properties. 28 These responsive materials are amphiphilic in nature, comprising both hydrophobic and hydrophilic components that migrate Additional Supporting Information may be found in the online version of this article.…”

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Hydrophobic‐hydrophilic surface switching properties of nonchain extended poly(urethane)s for use in agriculture to minimize soil water evaporation and permit water infiltration

Johnston

Freischmidt

Easton

et al. 2016

J of Applied Polymer Sci

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Preformed plastic films produced from nondegradable materials such as poly(ethylene) are widely used in agriculture to enhance crop production by modifying soil temperature, conserving soil water, and supressing weeds, but are generally removed and disposed of after each growing season. We aim to circumvent the need to retrieve and dispose of plastic films by using water‐borne, degradable polymers that can be sprayed directly onto the soil surface to form a barrier to reduce soil water evaporation. We report the synthesis and characterization of a series of nonchain extended poly(urethane)s (PUs) for this purpose, that were prepared from poly(dimethylsiloxane) (928.3 g mol−1) and poly(ethylene glycol) (1020 g mol−1). These new materials undergo hydrophobic‐hydrophilic switching of their surface properties when in contact with water, which we exploit as a means of minimizing water evaporation from soil when the polymer layer is dry (e.g., in sunny conditions), but permitting the infiltration of liquid water through the treatment into soil during rainfall or sprinkler irrigation. The surface wettability and restructuring phenomena leading to these fascinating properties are intensively investigated using water contact angle measurements, surface‐free energy estimates and depth profiling X‐ray photoelectron spectroscopy (XPS). Laboratory pot trials demonstrate that soil water evaporation reduced by more than 70% when soil was treated with a low loading of the polymer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44756.

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